Palynology and the Eco-Plant model of peat-forming wetlands of the Upper Triassic Haojiagou Formation in the Junggar Basin, Xinjiang, NW China

Abstract

Terrestrial deposits of the Triassic-Jurassic transition are well developed in the Junggar Basin, located in the Haojiagou Valley of Urumqi, Xinjiang Uygur Autonomous Region of Northwest China. This paper describes the palynology of a 10 m thick lignite bed from the Upper Triassic Haojiagou Formation (Rhaetian) with the aim of reconstructing the palaeovegetation and palaeoenvironment of a peat-forming wetland near the Triassic-Jurassic boundary. The palynoflora contains both Eurasian and Gondwanan elements, and is dominated by the spores and pollen of Bennettitales, Corystospermales, Ginkgoales, and Gleicheniales. At the Triassic/Jurassic boundary (Hettangian), the palynoflora significantly changes as Cyatheales spores become the dominant elements. We analyse assemblages in terms of an Eco-Plant model, which assigns the parent plants of the palynomorphs into five groups based on humidity and four groups based on temperature, and uses multivariate statistical analyses to infer palaeoclimate and palaeoenvironmental conditions. Results suggest that the palaeoclimate of the Rhaetian was generally wet and subtropical with short seasonal drought periods. Our analysis shows that an Eco-Plant model may be a useful tool to reveal past vegetation patterns and climate changes, applicable to other Mesozoic assemblages.

Full text

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5. Palynology and the Eco-Plant model of peat-forming wetlands of the Upper Triassic
Haojiagou Formation in the Junggar Basin, Xinjiang, NW China
Published article
Zhang, J., Lenz, O.K., Hornung, J., Wang, P., Ebert, M., Hinderer, M., 2020. Palynology and the Eco-Plant
model of peat-forming wetlands of the Upper Triassic Haojiagou Formation in the Junggar Basin, Xinjiang, NW
China. Palaeogeography, Palaeoclimatology, Palaeoecology 556, 109888.
https://doi.org/10.1016/j.palaeo.2020.109888
Abstract
Terrestrial deposits of the Triassic-Jurassic transition are well developed in the Junggar Basin, located in
the Haojiagou Valley of Urumqi, Xinjiang Uygur Autonomous Region of Northwest China. This paper
describes the palynology of a 10 m thick lignite bed from the Upper Triassic Haojiagou Formation (Rhaetian)
with the aim of reconstructing the palaeovegetation and palaeoenvironment of a peat-forming wetland near the
Triassic-Jurassic boundary. The palynoflora contains both Eurasian and Gondwanan elements, and is dominated
by the spores and pollen of Bennettitales, Corystospermales, Ginkgoales, and Gleicheniales. At the
Triassic/Jurassic boundary (Hettangian), the palynoflora significantly changes as Cyatheales spores become the
dominant elements. We analyse assemblages in terms of an Eco-Plant model, which assigns the parent plants of
the palynomorphs into five groups based on humidity and four groups based on temperature, and uses
multivariate statistical analyses to infer palaeoclimate and palaeoenvironmental conditions. Results suggest that
the palaeoclimate of the Rhaetian was generally wet and subtropical with short seasonal drought periods. Our
analysis shows that an Eco-Plant model may be a useful tool to reveal past vegetation patterns and climate
changes, applicable to other Mesozoic assemblages.
5.1 Introduction
At the Triassic-Jurassic boundary, a mass extinction event resulted in the loss of more than 30% of marine
genera, 50% of tetrapod species and a 95% turnover of megafloral species (Benton, 1995; McElwain et al.,
1999; Raup and Sepkoski, 1982). In the Junggar Basin, which is located in the Xinjiang Uygur Autonomous
Region of Northwest China (Figure 5-1), an almost continuous continental sedimentary record has been
documented from the Permian to the Cretaceous (Ashraf et al., 2010; Hornung and Hinderer, 2011). In
particular, in the Upper Triassic Haojiagou Formation located within the Haojiagou Valley of Urumqi, the
terrestrial deposits of the Triassic-Jurassic transition are well developed (Hornung and Hinderer, 2011; Lu and
Deng, 2005). They yield a diverse assemblage of non-marine animal and plant fossils (Sun et al., 2010a) as well
as fossil spores and pollen (Ashraf et al., 1999; Ashraf et al., 2010; Ashraf et al., 2001; Huang, 2006; Lu and
Deng, 2005, 2009). Palynological analysis offers a broad window for unravelling past vegetation patterns and
reconstructing climate changes (Li and Wang, 2016; Loinaze et al., 2018); thus, the microflora is crucial for
better understanding the terrestrial response of Triassic-Jurassic ecosystems to biotic and geological events in
the Junggar Basin.
Several independent studies have used palynological data to determine the general palaeoclimate during
parts of the Triassic and/or the Jurassic (e.g., Ashraf et al., 2010; Lu and Deng, 2009). However, most of these
studies have their focus on biostratigraphic issues and are based mainly on light microscopy (LM) that limits the
accurate identification of parent plant groups within the flora of the uppermost Upper Triassic. Therefore,
detailed palynological investigations especially using scanning electron microscopy (SEM) are needed for the
assignment of the palynomorphs to their parent plants. These assignments allow Late Triassic plant diversity,
and ecosystem-response to climate variations to be revealed across the Triassic-Jurassic boundary. Here, we
analyze 37 palynological samples from a 10 m thick lignite bed, from of the stratotype section of the Haojiagou
Formation using LM and SEM techniques to reconstruct the palaeovegetation and the palaeoenvironment of a
peat-forming wetland. Although significant palynological abundance changes are known from the Triassic-
Jurassic boundary, vegetational changes in the Haojiagou Formation are reported as relatively subtle (Ashraf et

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al., 2010; Lu and Deng, 2009). The generally similar values of δ13 Corg for the whole Haojiagou Formation
indicate that strong climatic variations can be excluded for the depositional time (Lu and Deng, 2009).
Therefore, the studied lignite section should also be representative for the climate change of the whole
Haojiagou Formation.
Figure 5-1 The lithological section of the Upper Triassic Haojiagou Formation from the Haojiagou Valley in the Junggar Basin, NW
China.
Note: A. The geographic position of Haojiagou Valley located at the southern margin of the Junggar Basin; B. Lithological section of the
Haojiagou Formation which is conformably overlain by the Lower Jurassic Badaowan Formation and conformably underlain by the
Norian Huangshanjie Formation; C. The sampled lignite seam is about 10 m thick and represents the thickest lignite bed within the

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Haojiagou Formation. There is no lithofacies change for the sampled coal-bearing part; D. Overview of the sampled lignite beds. Each of
the red square represents a palynological sample; E. Detail of the sampled lignite seam with palynological sample locations.
5.2 Geological setting and previous studies
The Junggar Basin is one of three large sedimentary basins located in the Xinjiang Uygur Autonomous Region
of Northwest China. It is flanked by the Altay Mountains in the northeast and separated from the Tarim and
Turpan Basins by the Tianshan Mountains in the south (Figure 5-1-A). Geologically, this area is part of the
Central Asian orogenic belt (Chen et al., 2012). The basin was cut off from marine influence during the
Carboniferous to Early Permian, when the Tianshan Mountains were folded up through the collision of the
cratonic Tarim block and the Eurasian plate (Allen et al., 1993; Sharps et al., 1989; Watson et al., 1987). Since
then, non-marine sediments have been deposited in the sedimentary basin, leading to a continuous series of
Permian to Late Cretaceous strata, which are unconformably overlain by Cenozoic sediments (Bian et al., 2010).
The abundant red beds present in the Lower and Middle Triassic stratigraphic successions demonstrate that this
region was subjected to a relatively arid climate during these times. In the Upper Triassic (Rhaetian) Haojiagou
Formation charcoal and oriented wood fragments prove that this region was exposed to a relatively humid
climate (Hendrix et al., 1992).
The stratotype section of the Haojiagou Formation (43°39'54.47" N, 87°12'40.67" E) is located in the
Haojiagou valley, about 40 km southwest of Urumqi, the capital city of the Xinjiang Uygur Autonomous
Region. The formation is about 290 m in thickness, mainly composed of grey and greyish-yellow sandstones
and conglomerates intercalated with mudstones, sandy mudstones, and lignite beds (Figure 5-1-B). It is
conformably underlain by the Norian Huangshanjie Formation and conformably overlain by the Lower Jurassic
Badaowan Formation.
The Haojiagou Formation is characterized by terrestrial and marginal lacustrine depositional
environments and can be subdivided into a lower and an upper part. The Lower Haojiagou Formation is
composed of coaly, silty and clayey lithofacies types deposited in a lacustrine delta top with fluvial and back-
swamp environments (Hornung and Hinderer, 2011). Fusain (Fiber coal) is particularly common in the lignite
deposits, which is formed almost exclusively by forest fires (Ligouis, 2001). A distal alluvial-plain environment
with cross-bedded sandstone and conglomeratic units characterizes the Upper Haojiagou Formation (Hornung
and Hinderer, 2011). This formation yielded abundant plant macrofossils (Lu and Deng, 2005; Sun et al.,
2010a). Among these, Cycadocarpidium erdmanni, Cycadocarpidium swabii, and Neocalamites hoerensis are
important elements in the Late Triassic floras of Eurasia. Therefore, the Haojiagou flora is characterized by the
Glossophyllum/Cycadocarpidium assemblage, which demonstrates a Late Triassic age, probably Norian-
Rhaetian (Sun et al., 2010a). Palynologically, the Haojiagou Formation is characterized by the
Concavisporites/Duplexisporites problematicus/Ricciisporites tuberculatus zone indicating close similarities to
other Late Triassic Eurasian microfloras, e.g., of Iran or Germany (Ashraf et al., 2010; Lu and Deng, 2005).
The Triassic-Jurassic boundary occurs at the base of the succeeding Badaowan Formation in this section
(Ashraf et al., 1999; Ashraf et al., 2010; Lu and Deng, 2005, 2009; Sun et al., 2010a; Tong et al., 2019).
However, the exact position of the Triassic Norian-Rhaetian boundary is under discussion. One view uses the
base of the Haojiagou Formation as the boundary (e.g., Ashraf et al., 1999; Ashraf et al., 2010; Ashraf et al.,
2001); whereas another view suggests that the Haojiagou formation contains the Upper Norian Stage and the
whole Rhaetian Stage (e.g., Tong et al., 2019). Therefore, the boundary between the Norian and Rhaetian Stages
is not defined yet and, at present, the global stratotype and boundary markers of Norian-Rhaetian have not yet
been decided (Tong et al., 2019).
5.3 Materials and methods
5.3.1 Sampling and sample processing
Most of the lignite beds in the Haojiagou Formation are less than 3 m in thickness. Only one lignite seam
with a thickness of about 10 m occurs in the Haojiagou Formation, about 45 m above the top of the
Huangshanjie Formation and about 235 m below the base of the Badaowan Formation (Figures 5-1-B, C, D,
and E). However, it is intercalated with a sandy bed around 1 m thick that is laterally not continuous and most

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likely represents a channel fill. The lignite bed belongs to the Upper Norian or the Lower Rhaetian Stage. For
the lignite seam, a delta-top environment can be assumed characterized by small channels and interbedded
crevasse-splay sediments (Hornung and Hinderer, 2011).
The 37 samples that were analyzed were taken from the lignite seam with a sample distance of c. 0.3 m.,
labelled from bottom to top with HJG 01 to HJG 37. Palynological preparation of c. 100 g material per sample,
including treatment with hydrochloric acid (HCl), hydrofluoric acid (HF) and potassium hydroxide (KOH),
followed the standard method as described by Kaiser and Ashraf (1974). After sieving through a 10 μm mesh
screen, residues were oxidized using nitric acid (HNO3) or hydrogen peroxide (H2O2) to improve transparency
of the palynomorphs. For each sample, the residues were rinsed with 10 litres of distilled water, sieved, and then
stored in 3 ml water vials. For each sample, at least one slide was made for LM analysis by mounting 0.025 ml
of residue mixed with liquid on the slide using glycerine jelly. For 12 of the samples (HJG 01-12), 0.01 ml of
residue was taken and dropped on an aluminium stub with an adhesive carbon pad with an area of
approximately 1 cm2 and dried at approximately 25 °C for 48 h to be used for SEM analysis at the ESEM Lab
of the Technische Universität Darmstadt, using a voltage of 12.5-15 kV. To get rid of charging problems, some
SEM samples have been coated with gold. All residues, carbon pads, and slides are stored at the Institute of
Applied Geosciences, Technische Universität Darmstadt, Germany.
5.3.2 Qualitative and quantitative palynological analysis
SEM can reveal features of palynomorphs at the species level not observable by LM (Hesse et al., 2018).
Therefore, SEM was mainly used for the exact identification of palynomorphs while LM was taken for
quantitative analysis. For each sample, about 200 palynomorphs were counted using an Olympus light
microscope (Olympus BX40) at ×400 magnification. Additionally, for a comprehensible study, each counted
grain has been documented by a digital picture. To reconstruct the botanical affinities of the pollen and spores,
the systematic scheme of extant plants provided by Goffinet and Buck (2004) and Smith et al. (2006) and the
systematic scheme of fossil plants of Taylor et al. (2009) have been used.
The pollen diagrams, produced by our online database Sporopollen (http://www.sporopollen.com), show
the abundance of the palynomorphs related to their parent plants or Eco-Plant groups in percentages.
5.3.3 Eco-Plant model
The Ecogroup classification based on the growth-form of plants (Eco-Plant) was established by the
pioneering work of Warming (1895) and Schimper (1898). They analyzed diverse plant associations with
relation to principal climatic elements such as water, heat, light, and air. The Eco-Plant model has been widely
used for extant (e.g., Baeza et al., 2010; Godin, 2017; Sheremetov and Sheremetova, 2017; Veisberg, 2017),
Cenozoic (e.g., Bozukov et al., 2009; Yang et al., 2013; Yurtsev, 2001), Mesozoic (e.g., Hill, 2017;
Vakhrameev, 1991), and Paleozoic palaeoenvironmental reconstructions (e.g., Bashforth et al., 2014; Wang,
1999b). It is also applied by palynologists for palaeoenvironmental reconstructions using dispersed sporomorphs
from the Cenozoic (e.g., Aranbarri et al., 2014; Kern et al., 2012; Popescu et al., 2006; Suc and Fauquette, 2012)
and Mesozoic (e.g., Césari and Colombi, 2016; Hochuli and Vigran, 2010; Mueller et al., 2016; Roghi et al.,
2010; Visscher and van der Zwan, 1981; Wang et al., 2013; Wang et al., 2005; Zhao et al., 2014).
For the analysis of palaeoenvironmental and palaeoclimate variations throughout the analyzed record of
the Haojiagou Formation, we use an Eco-Plant model that assesses the effect of humidity (EPH) and the effect
of temperature (EPT) that has also been used by other authors for Mesozoic records (e.g., Hill, 2017;
Vakhrameev, 1991).
EPH separates the palynomorphs and their parent plants into five groups (Runhaar et al., 1997;
Sheremetov and Sheremetova, 2017):
a) Hydrophytes are aquatic plants that are completely or mostly submerged in water as well as being
amphibious plants that grow both in water and in excessively wet habitats along the shorelines of reservoirs, in
areas of shallow water, and in swamps.

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b) Hygrophytes are plants that are living in excessively wet habitats with a high air and soil moisture but
usually no water stagnation on the surface, such as the lower tiers of wet forests, or open habitats with
constantly wet soils and wet air.
c) Mesophytes are plants that have some ability to resist periods of drought or to regulate their water
metabolism in moist areas such as dry meadows or pine forests.
d) Xerophytes are plants that can resist long periods of drought and are living in stony steppes and dry
rock outcrops.
e) Euryphytes are plants that are adapted to great variations in humidity.
EPT categorizes the palynomorphs and their parent plants into four groups (Nix, 1982; Prentice et al.,
1996; Suc and Fauquette, 2012):
a) Megathermic plants inhabiting regions such as tropics and subtropics with a mean annual air
temperature (MAT) above 20 °C.
b) Mesothermic plants inhabiting regions such as warm temperate zones with a MAT between 14 to 20
°C.
c) Microthermic plants inhabiting regions such as the cool temperate zone, the subarctic zone, or elevated
areas with a MAT below 14 °C.
d) Eurythermic plants that can tolerate a wide range of temperatures.
The Sporomorph Ecogroup Model (SEG model) of Abbink et al. (2004b) is also commonly used for
Mesozoic palaeoenvironmental reconstructions of Europe and some parts of China (e.g., Abbink et al., 2001;
Abbink et al., 2004a; Abbink et al., 2004b; Heunisch et al., 2010; Li and Wang, 2016; Li et al., 2016). It
represents a simplified Eco-Plant model. According to hydrologic and temperature conditions in the Eco-Plant
model, plants are classified into different EPH and EPT groups due to their climatic preferences. In contrast, in
the SEG model, plants are classified as belonging to a wetter, drier, warmer, or cooler group. Besides, in the
SEG model, due to uncertain botanical affinities of some palynomorphs, several plants indicating a different
climate and environment are categorized in the same group. For example, in the Eco-Plant model, Ginkgoales
are classified as mesophytes and mesothermic plants, but Bennettitales as hygrophytes and megathermic plants
(see below). In contrast, in the SEG model, Ginkgoales, Cycadales, and Bennettitales are all included in the
same group of the “Lowland SEG” and indicate a “drier” and “warmer” climate, since the pollen of Ginkgoales,
Cycadales, and Bennettitales can usually only be distinguished under SEM or TEM (Abbink et al., 2004b).
Therefore, we have chosen Eco-Plant since it allows for more detailed and precise statements on palaeoclimate
than the SEG model.
However, for most of the Mesozoic dispersed sporomorphs, the application of Eco-Plant is limited,
because either their assignment to a specific ecogroup remains uncertain or the botanical affinities to plant taxa
are unclear. Therefore, it is first important to identify their botanical affinities, because otherwise their Eco-Plant
implications are not reliable. Therefore, we have systematically reviewed the Mesozoic dispersed sporomorphs
related with Bryophytes, Gymnosperms, and Pteridophytes and linked them to their possible parent plants as
well as Eco-Plant. The primary results are presented in our online database
(http://www.sporopollen.com/sporefamilygenus.php).
5.3.4 Statistical analysis
We present complex and multivariate pollen data and use different ordination techniques to show
ecological trends. For revealing abundance patterns in the data set, numerical analyses of palynological data
were undertaken using plant orders and families as represented in Table 5-1, 2. Thereby, some of the

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sporomorph taxa were lumped together because of similar botanical/ecological affinities such as
Bharadwajipollenites and Ricciisporites, which were treated as Bennettitales. Only one species, Quadraeculina
with unknown botanical affinity, was used without assignment to a plant family or order in the analyses. For
further analyses, we used the different EPH and EPT ecogroups to reveal palaeoecological and palaeoclimate
trends in the data set.
Numerical treatment of the palynological data relied on using PAST 3.26 (Hammer et al., 2001). Prior to
ordination the raw data values were Wisconsin double standardized. Wisconsin standardization scales the
abundance of each taxon to its maximum value and represents the abundance of each taxon by its proportion in
the sample (Mander et al., 2010). This equalizes the effects of rare and abundant taxa and removes the influence
of sample size on the analysis (Jardine and Harrington, 2008; van Tongeren, 1995).
Constrained cluster analysis using the unweighted pair-group average (UPGMA) method and a Euclidean
distance has been applied to the plant order/families data set to identify samples with similar palynomorph
contents. We selected constrained analysis for Q-mode defined sample clusters to group only stratigraphically
adjacent samples during the clustering procedure and to identify a zonation in the record.
To reveal the underlying pattern as well as ecological gradients, a principal component analysis (PCA)
was implemented. PCA was chosen as the appropriate multivariate model, because a gradient analysis
(detrended correspondence analysis, DCA; Hill and Gauch (1980)) using CANOCO 4.5 (Leps and Smilauer,
2003) determined a length of 1.851 SD (units of average standard deviation of species turnover). This is a
measure of unimodality for the gradient represented by the first DCA axis of the plant order/families data set
and 1.359 SD for the Eco-Plant data set. Following Leps and Smilauer (2003), a gradient length less than 3 SD
indicates an approximately linear trend in species composition, and the linear response model of the PCA should
be used rather than a unimodal response model like (detrended) correspondence analysis (CA/DCA).
5.4 Results
5.4.1 Qualitative analysis
Among the 37 samples, 30 of them preserve abundant palynomorphs. In total, 570 SEM pictures have
been taken for identification and assignment to their parent plants as well as 6436 LM pictures for the
quantitative analysis. All pictures are stored in the online database Sporopollen (http://www.sporopollen.com).
Finally, 19 genera of palynomorphs have been identified (Table 5-1). All recognized palynomorph genera are
presented in Figures 5-2, 3 as SEM and in Figures 5-4, 5 as LM images. In the following, 18 palynomorph
genera are assigned to parent plant orders or families. This is based on information taken from the literature as
well as own assignments based on SEM images of the various palynomorphs and the study of the ultrastructure
of the palynomorph wall. Furthermore, we allocate the recognized plant order and families to EPH and EPT
categories. The relevant plant fossils discovered in this region (Lu and Deng, 2005; Shi et al., 2015; Sun et al.,
2010a; Yang et al., 2006) are also listed here (Table 5-2). For the identified plants, the fossils of Lycopodiales,
Notothyladaceae, and Sphagnales have not been discovered in this region yet. Only one of the recognized
genera in the pollen assemblage of the Haojiagou Formation, Quadraeculina (Figures 5-3-N, 5-F), could not
been assigned to a specific plant order and family. The various plant orders and families are listed below in
alphabetical order.
5.4.1.1 Bennettitales
The fossils of Nilssoniopteris (Lu and Deng, 2005) and Otozamites (Sun et al., 2010a) have been
discovered in the Haojiagou Formation. Two pollen genera that have been found in the palynomorph
assemblage, Bharadwajipollenites (Figures 5-2-E-H, 4-D-E) and Huabeisporites (Figures. 5-3-F-H, 5-A), can
be assigned to the order of Bennettitales. The only difference between Huabeisporites and Ricciisporites is that
the sculpture of Huabeisporites is weaker (Song et al., 2000). Ricciisporites was originally thought to be a spore
and morphologically comparable with the extant liverwort spore of Riccia and the in situ fossil spore of
Ricciopsis (Balme, 1995). However, based on transmission electron microscope (TEM) and SEM studies of
Ricciisporites it is obvious that the spore is equipped with a single distal colpus and an ultrastructure of the

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palynomorph wall characterized by a granular inner sexine as well as an electron-dense laminated nexine
(Mander et al., 2012). This demonstrates close morphological resemblance to pollen produced by the in situ
bennettitean pollen of Cycadeoidea dacotensis (Mander et al., 2012). The sculpture of Huabeisporites (Figure
5-3-G) is also comparable with the in situ pollen of Weltrichia setosa reported by van Konijnenburg-van Cittert
(1971). Bharadwajipollenites is comparable to the in situ pollen of Haitingeria krasseri (Balme, 1995).
Furthermore, the sculpture of Bharadwajipollenites (Figures. 5-2-F, H) is comparable with the in situ pollen of
Cycadeoidea dacotensis reported by Osborn and Taylor (1995) and Taylor (1973).
Table 5-1 Spore and pollen percentage values from the studied lignite bed of the Haojiagou Formation
Note: Minimum and maximum values for each of the sporomorph taxa are marked in grey.
The Bennettitales were distributed from the Triassic to the Cretaceous in both, northern and southern
hemispheres and are believed to be 1- to 3-m-tall shrubs (Pott and McLoughlin, 2014; Taylor et al., 2009). They
are divided into two separate families: The Williamsoniaceae with mainly Late Triassic and Jurassic
representatives and the Cycadeoidaceae (Bennettitaceae) with mainly Cretaceous representatives (Popa, 2019).
Nilssoniopteris (Zhao et al., 2018) and Otozamites (Wang et al., 2008) have been found mainly in the
subtropical-tropical climate zone during the Mesozoic. Leaves of the Williamsoniaceae are commonly
associated with coaly facies and the parent plants may have been specialized to colonize the surfaces of mires
(Pott and McLoughlin, 2014). Therefore, the Bennettitales were generally hygrophytes and megathermic plants.

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Table 5-2 Spore and pollen list from the studied lignite bed of the Haojiagou Formation with related plant affinities and Eco-
Plant groups that assess the effect of humidity (EPH) and the effect of temperature (EPT).
Note: ● plant fossils with confirmed affinities found in Haojiagou section of Haojiagou Formation; (?): plant fossils with problematic
☆affinities found in Haojiagou section of Haojiagou Formation; : plant fossils with confirmed affinities found in the Early-Middle
★Jurassic Sangonghe Formation in Junggar Basin; : plant fossils with confirmed affinities found in Middle-Late Triassic Karamay
Formation in Junggar Basin; the sporomorph affinities are based on this study (see below); the plant fossils are based on literature (e.g.,
He et al., 2017; Lu and Deng, 2005; Shi et al., 2015; Sun et al., 2010a; Yang et al., 2006).

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Figure 5-2 Spores and pollen grains under SEM from the studied lignite bed of the Haojiagou Formation: all of the primary images can
be visited at: http://www.sporopollen.com/sporepaperpic.php?paper=p3_2020.
Note: A. Angiopteridaspora denticulata Chang, 1965; B-C. Annulispora folliculosa (Rogalska) de Jersey, 1959: B. proximal view, C.
distal view; D. Aratrisporites scabratus Klaus, 1960 coated with gold; E-H. Bharadwajipollenites wielandii Jain, 1968 coated with gold:
E. overview of pollen, F. detail of exine sculpture of E, G. overview of pollen, H. detail of exine sculpture of G; I. Calamospora
nathorstii (Halle) Klaus, 1960; J. Cyathidites minor Couper, 1953; K. Dictyophyllidites harrisii Couper, 1958; L-M. Discisporites
acinosus Zhang, 1984 coated with gold: L. proximal view with laesurae which are branched at the end (red arrows), M. distal view with
narrow ring of thinner exine (red arrow); N-O. Duplexisporites generalis Deak 1962 emend. Playford et Dettmann, 1965: N. proximal
view with crassitude on equator and kyrtome, O. distal view with coarse ridges; scale bar: 10µm.

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Figure 5-3 Spores and pollen grains under SEM from the studied lignite bed of the Haojiagou Formation: all of the primary images can
be visited at: http://www.sporopollen.com/sporepaperpic.php?paper=p3_2020.
Note: A-B. Foveolatitriletes potoniei Mädler, 1964 coated with gold; C-D. Ginkgocycadophytus nitidus (Balme) De Jersey, 1962 coated
with gold: C. overview of pollen, D. detail of exine sculpture of C; E. Hamulatisporis hamulatis Krutzsch, 1959 coated with gold; F-H.
Huabeisporites sp coated with gold: F, H. overview of pollen, G. detail of exine sculpture of F; I-J. Osmundacidites alpinus Klaus, 1960
coated with gold; K. Pinuspollenites alatipollenites (Rouse) Liu; L-M. Pteruchipollenites thomasii Couper, 1958 coated with gold; N.
Quadraeculina sp. coated with gold; O. Sphagnumsporites stereoides (Pot. et Ven) Raatz, 1937; scale bar: 10 µm.

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Figure 5-4 Spores and pollen grains under LM from the studied lignite bed of the Haojiagou Formation: all of the primary images can be
visited at: http://www.sporopollen.com/sporepaperpic.php?paper=p3_2020.
Note: A. Angiopteridaspora denticulata Chang, 1965; B. Annulispora folliculosa (Rogalska) de Jersey, 1959; C. Aratrisporites
scabratus Klaus, 1960; D-E. Bharadwajipollenites wielandii Jain, 1968: D. sculpture with big pit, E. sculpture with small pit; F.
Calamospora nathorstii (Halle) Klaus, 1960; G. Cyathidites minor Couper, 1953; H. Dictyophyllidites harrisii Couper, 1958; I.
Discisporites acinosus Zhang, 1984: with laesurae which are branched at the end (see red arrows) also with narrow ring of thinner exine
(red arrow); J. Duplexisporites generalis Deak 1962 emend. Playford et Dettmann, 1965: proximal view with crassitude on equator,
kyrtome on proximal face, and coarse ridges on distal face; K. Foveolatitriletes potoniei Mädler, 1964; L. Ginkgocycadophytus nitidus
(Balme) De Jersey, 1962; M. Hamulatisporis hamulatis Krutzsch, 1959; scale bar: 20 µm.

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Figure 5-5 Spores and pollen grains under LM from the studied lignite bed of the Haojiagou Formation: all of the primary images can be
visited at: http://www.sporopollen.com/sporepaperpic.php?paper=p3_2020.
Note: A. Huabeisporites sp; B. Osmundacidites alpinus Klaus, 1960; C. Pinuspollenites alatipollenites (Rouse) Liu; D.
Protohaploxypinus sp.; E. Pteruchipollenites thomasii Couper, 1958; F. Quadraeculina sp.; G. Sphagnumsporites stereoides (Pot. et
Ven) Raatz, 1937; scale bar: 20 µm.
5.4.1.2 Cheirolepidiaceae
Hirmeriella fossils have been found in the Early-Middle Jurassic Sangonghe Formation in this region
(Yang et al., 2006). One pollen genus, Discisporites (Figures. 5-2-L-M, 4-I), that has been recognized in the
palynomorph assemblage can be assigned to the family of Cheirolepidiaceae. Discisporites is thought to be
comparable with Classopollis (Alvin, 1982) and Circulina (Norris, 1965). Classopollis has been previously
reported for the Haojiagou Formation (Huang, 2006).

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It is possible that the conifers of the Cheirolepidiaceae are derivative of the Discisporites producing plants
(Alvin, 1982). Without SEM data, Discisporites has also been described as Limatulasporites (e.g., Huang, 2006;
Lu and Deng, 2009). However, the distal face of Discisporites has a narrow ring of a thinner exine which is
called operculum (Figure 5-2-M), while Limatulasporites has a crassitude on the distal face and an equatorial
flange called cingulum (Song et al., 2000). Although the difference is remarkable, under LM, it is difficult to
distinguish. The operculum (Figure 5-2-M), which has never been found on spores, is the most remarkable
character for the pollen of Cheirolepidiaceae. However, the Y-mark on a pollen grain is rare. Nevertheless, three
cones have been found attached to Tomaxellia biforme branches, which yielded Classopollis pollen showing
proximal folds reproducing a Y-mark (Archangelsky and Gamerro, 1967). The in situ pollen is also comparable
to Discisporites.
The Cheirolepidiaceae are a large family of Mesozoic conifers, plants of which were large trees, woody
shrubs, and possibly herbs (Steart et al., 2014). Evidence from sediments and cuticle morphology, most notably
the sunken papillate stomata, indicate that the plants were adapted to xeric habitats and grew in brackish coastal
mires as well as on the margins of freshwater rivers and lakes (Alvin, 1982; Steart et al., 2014). Generally, they
are drought resistant, thermophilous shrubs and trees with a preference for subtropical to tropical climates, and
were never dominant in cool regions (Francis, 1983; Vakhrameev, 1991). They were also adapted to semi-arid
and arid low-lying water-margin environments that produce mud flats (Taylor et al., 2009; Vakhrameev, 1991).
Therefore, they can be described as xerophytes and megathermic plants.
5.4.1.3 Corystospermales
The fossils of Thinnfeldia are known from the Haojiagou Formation (Sun et al., 2010a). One pollen genus,
Pteruchipollenites (Figures 5-3-L-M, 5-E), that have been found in the palynomorph assemblage can be
assigned to the order of Corystospermales. Pteruchipollenites is comparable with the in situ pollen of Pteruchus
(Osborn and Taylor, 1993; Taylor et al., 1984).
The plants of Corystospermales were probably small to large woody shrubs and trees that originated in the
late Paleozoic and spread worldwide in the Mesozoic during the climate warming of Late Permian/Early
Triassic (Taylor et al., 2006; Taylor et al., 2009). Dicroidium apparently originated in the palaeotropics during
the late Palaeozoic and subsequently migrated southwards, eventually colonizing the entire extra-tropical region
of Gondwana during the Middle and Late Triassic (Kerp et al., 2006). This geographic expansion was
accompanied by a remarkable diversification, enhanced by adaptations to different environmental conditions
(Bomfleur and Kerp, 2010). The earliest representatives of Dicroidium flourished in the palaeotropics under a
hot, humid climate with high annual rainfall and short dry seasons (Abu Hamad et al., 2008; Uhl et al., 2007).
The stem anatomy of Cuneumxylon from Argentina indicates that the plants were well adapted to tolerate
prolonged periods of water stress in seasons of drought (Artabe and Brea, 2003). The environment of fossil
Cuneumxylon correlate with that of an extant subtropical seasonal forest (dry monsoonal forests) (Brea et al.,
2008). Although the leaf fossil of Pachypteris papillosa from Yorkshire is thought to be a large mangrove shrub
forming a thicket beside the river, it should also be noted that the leaf of Pachypteris lanceolata from Yorkshire
shows no link with marine horizons (Harris, 1983). Therefore, the Corystospermales were mesophytes and
megathermic plants.
5.4.1.4 Cyatheales
Cladophlebis fossils have been found in the Haojiagou Formation and Coniopteris in the Lower Jurassic
Sangonghe Formation (Sun et al., 2010a). Two spore genera, Duplexisporites (Figures 5-2-N-O, 4-J) and
Cyathidites (Figures 5-2-J, 4-G), that have been identified in the palynomorph assemblage can be assigned to
the order of Cyatheales. Duplexisporites is comparable with the extant spore of Cibotium (Potonié, 1967;
Srivastava, 1987), whereas Cyathidites is probably the in situ spore of Alsophilites (Shuklina and Polevova,
2007) as well as the extant spore of Dicksonia (Dettmann, 1963).
The foliage of Cladophlebis may point either to the Gleicheniales (Yang et al., 1997), Cyatheales
(Nagalingum and Cantrill, 2015), or Osmundales (Taylor et al., 2009), but currently spores that are comparable
to Duplexisporites and Cyathidites have never been found as an in situ or extant spore of Gleicheniales or

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Osmundales. Therefore, it can be inferred that at least some of the Cladophlebis fossils found in the Haojiagou
Formation are related to the Cyatheales.
Cyatheales originated as early as the Jurassic (Taylor et al., 2009). Extant species of Cyatheales are tree
ferns concentrated in the tropics where they are most numerous in the montane to alpine vegetation. Many
species occur in the undergrowth of moist forests, often in ravines. Others prefer more open habitats, even
swamps, and some grow preferentially in cleared areas (Kramer and Green, 1990). Therefore, Cyatheales can
generally be identified as hygrophytes and megathermic plants.
5.4.1.5 Equisetales
Fossils of Equisetites and Neocalamites have been found in the Haojiagou Formation (Sun et al., 2010a).
One spore genus Calamospora (Figures 5-2-I, 4-F) that has been recognized in the palynomorph assemblage
can be assigned to the order of Equisetales. Calamospora is comparable with the in situ spore of Equisetites
(Kelber and van Konijnenburg-van Cittert, 1998).
Extant Equisetales consist of a single genus Equisetum (Smith et al., 2006), which is a herbaceous
perennial plant. The Mesozoic plants of Equisetales are more or less comparable with extant Equisetum (Taylor
et al., 2009). The mode of fossil Neocalamites tubulatus preservation serves to prove the idea that the parent
plant, resembling recent Equisetum communities, had grown along a lake shore inhabited by a near-water
hygrophilous plant community of helophytes (Naugolnykh, 2009). Extensive fossil Equisetites arenaceus
populations occurred in marginal strips along an anastomosing river system. Dense Equisetites arenaceus reeds
also invaded the levee belt as well as hygromorphic environments surrounding standing waterbodies in a flood
plain (Kelber and van Konijnenburg-van Cittert, 1998). Equisetum has been reported from numerous localities
worldwide, where they are primarily plants of open, sunny sand banks along river and lake margins, in marshes,
and in other wet places (Taylor et al., 2009). Although the greatest concentrations of extant species are found
between 40° and 60° northern latitude, Equisetum is found around the world from the southern parts of South
America and Africa to above the Arctic Circle (Kramer and Green, 1990). Therefore, they are generally
hygrophytes and eurythermic plants.
5.4.1.6 Ginkgoales
Ginkgoites fossils have been reported for the Haojiagou Formation (Sun et al., 2010a). One pollen genus
Ginkgocycadophytus (Figures. 5-3-C-D, 4-L) that has been found in the palynomorph assemblage can be
assigned to the order of Ginkgoales. Ginkgocycadophytus is comparable with the in situ pollen of ginkgoalean
Allicospermum (Zavialova et al., 2014).
Ginkgo biloba, the only extant species of the Ginkgoales, is a kind of deciduous tree that can be 30 m in
height and 9 m in trunk circumference (Kramer and Green, 1990). Mesozoic ginkgoalean plant fossils are found
widely in fossil records, except at the Equator and in Antarctica. After the Cretaceous, ginkgoalean plants began
to decline rapidly, their abundance was reduced, and their distribution narrowed to only temperate forests
(Wang et al., 2017). In spite of their broad adaptability, however, it appears that ginkgoaleans on the whole were
more abundant and diverse in mesic, warm temperate to temperate climates similar to those in the relictual area
of their living representative Ginkgo biloba (Zhou, 2009). Therefore, they are mesophytes and mesothermic
plants.
5.4.1.7 Gleicheniales
Fossils of Dictyophyllum, Clathropteris, and Hausmannia have been found in the Haojiagou Formation
(Lu and Deng, 2005; Sun et al., 2010a). The spore genus Dictyophyllidites (Figures. 5-2-K, 4-H) that has been
identified in the palynomorph assemblage can be assigned to the order of Gleicheniales. Dictyophyllidites is
comparable with the in situ spores of Dictyophyllum (Dettmann, 1963) and Phlebopteris (Cranwell and
Srivastava, 2009). Dictyophyllidites is also comparable with the extant spores of Cheiropleuria bicuspis
reported by Wang and Dai (2010) and Cheiropleuria bicuspus reported by Tryon and Lugardon (1991).

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Gleicheniales can be traced back to the Carboniferous (Taylor et al., 2009). Extant Gleicheniales are
terrestrial ferns of rather small to very large sizes (Smith et al., 2006). All of them are heliophilous terrestrial
ferns in tropical to subtropical regions and most species occur in open, often strongly disturbed and/or pioneer
habitats on damp soils (Kramer and Green, 1990; Qian and Chen, 2006). Some plants, such as Gleichenites,
Piazopteris, and Weichselia were adapted to semiarid or arid climates during the Mesozoic (van Konijnenburg-
van Cittert, 2002). Of course, this does not imply that all plants of Gleicheniales showed the same ecological
adaptations. Therefore, they are generally mesophytes and megathermic plants.
5.4.1.8 Lycopodiales
Two spore genera Foveolatitriletes (Figures 5-3-A-B, 4-K) and Hamulatisporis (Figures. 5-3-E, 4-M)
that have been found in the palynomorph assemblage can be assigned to the order of Lycopodiales.
Foveolatitriletes is comparable with the extant spore of Phylloglossum drummondii reported by Tryon and
Lugardon (1991). The remarkable character of Foveolatitriletes is that the sculpture on its proximal face is
much weaker than on its distal face, which is also the common character of extant spores of Lycopodiales.
Hamulatisporis is comparable to the extant spore of Lycopodium (Traverse and Ames, 1979). Based on our
study, the spore of Hamulatisporis (Figure 5-3-E) is more comparable to the extant spore of Palhinhaea cernua
reported by Giacosa et al. (2016).
The Lycopodiales includes homosporous, eligulate, usually dichotomously branched herbaceous plants,
whose fossils of Lycopodium have been described from records ranging from Devonian to Pleistocene (Taylor et
al., 2009). Extant species of Lycopodiales are almost cosmopolitan, being absent only from arid areas. The
greatest species concentration is in humid, tropical, montane forests and in humid, tropical, alpine vegetation
(Kramer and Green, 1990). Therefore, they are generally hygrophytes and eurythermic plants.
5.4.1.9 Marattiales
The fossils of Bernoullia and Danaeopsis have been discovered in the Haojiagou Formation (Sun et al.,
2010a). One spore genus Angiopteridaspora (Figures 5-2-A, 4-A) that has been found in the palynomorph
assemblage can be assigned to the order of Marattiales. Angiopteridaspora is comparable to the extant spore of
Angiopteris (Kremp et al., 1967). Based on our study, Angiopteridaspora (Figure 5-2-A) is also comparable
with the extant spore of Protomarattia tonkinensis reported by Tryon and Lugardon (1991).
Extant Marattiales are terrestrial ferns distributed exclusively in tropical and subtropical regions under
primary and secondary wet forests or along the bank of streams (Kramer and Green, 1990). The plants of
Mesozoic Marattiales have always lived under rather warm, moist circumstances often probably as understory in
forests (van Konijnenburg-van Cittert, 2002). Therefore, they are generally hygrophytes and megathermic
plants.
5.4.1.10 Notothyladaceae
One spore genus Annulispora (Figures 5-2-B, C, 4-B) that has been found in the palynomorph
assemblage can be assigned to the family of Notothyladaceae. This type of microspore is trilete with a
considerably thick exine, usually thicker in the distal than in the proximal face. On distal face, there is a
characteristic projection which is a hollow circle. Annulispora (Figures 5-2-B, C) is comparable with the extant
spore of Phaeoceros skottsbergii reported by Warny et al. (2012). The extant spore of Notothylas levieri
reported by Chantanaorrapint (2015) is also comparable with Annulispora, but on its distal face there is a solid
circular projection rather than a hollow circular projection.
Extant Notothyladaceae are a kind of hornwort including Mesoceros, Notothylas, Paraphymatoceros, and
Phaeoceros (Söderström et al., 2016). They can be found in moist soil from warm tropical regions to cold
circumboreal regions (Boros and Járai-Komlódi, 1975; Zhang et al., 2006). They are hygrophytes and
eurythermic plants.
5.4.1.11 Osmundales

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The fossils of Rireticopteris and Todites have been found in the Haojiagou Formation (Sun et al., 2010a).
One spore genus Osmundacidites (Figures 5-3-I-J, 5-B) that has been recognized in the palynomorph
assemblage can be assigned to the order of Osmundales. Osmundacidites is comparable to the extant spore of
Osmunda or the in situ spore of Todites (Dettmann, 1963).
Extant species of Osmundales are terrestrial ferns distributed throughout most temperate and tropical
regions in sites with either high edaphic or high atmospheric moisture (or both) (Kramer and Green, 1990;
Tryon and Lugardon, 1991). During the Mesozoic, the Osmundales were probably ferns that grew under warm,
humid circumstances, either along riverbanks, or in freshwater marshes where they often formed peat resulting
in coal (van Konijnenburg-van Cittert, 2002). However, extant species of Osmundales, such as Osmunda
claytoniana, can also be distributed in the cooler montane regions of the Himalaya and Far East of Russia
(Ching and Shing, 1990; Qian and Chen, 2006). Therefore, they are generally hygrophytes and eurythermic
plants.
5.4.1.12 Peltaspermales
The fossils of Glossophyllum and Sphenobaiera have been discovered in the Haojiagou Formation (Sun et
al., 2010a), and Scytophyllum have been found in the Upper Triassic Karamay Formation from the Junggar
Basin (He et al., 2017). One pollen genus Protohaploxypinus (Figure 5-5-D) that has been identified in the
palynomorph assemblage can be assigned to the order of Peltaspermales. It is comparable with the in situ pollen
of Permotheca (Zavialova and Karasev, 2015) and Nidpuria (Balme, 1995). Glossophyllum and Sphenobaiera
are probably plants of the Peltaspermales (Meyen, 1984). However, other authors indicate that they may belong
to other plant orders such as the Ginkgoales (Taylor et al., 2009; Zhou, 2009). Nevertheless, the bisaccate pollen
of Protohaploxypinus is not comparable with any monosulcate pollen of the Ginkgoales. Therefore, at least
Protohaploxypinus is related with Peltaspermales.
The seed ferns of Peltaspermales are believed to originate from tropical areas during the Late
Pennsylvanian and disappeared in the Mesozoic with fossils distributed globally (Taylor et al., 2009; Wan et al.,
2016). They might have been shrub-like plants (He et al., 2017). Epidermal features of Glenopteris splendens
are consistent with those extant plants adapted to (seasonal) moisture limitation and elevated soil and ground
water salinity (Krings et al., 2005). Furthermore, epidermal features indicate that Peltaspermum martinsii has
been grown in drier or saline influenced biotopes (Poort and Kerp, 1990) and that Peltaspermum retensorium
has lived in a relatively dry habitat (Naugolnykh and Kerp, 1996). Also plants from the Sobernheim Autunia
conferta population have been grown in a mineral soil under relatively dry conditions (elevated sandy lake
margins, sand and river banks) (Kerp, 1988). Although the sedimentary analysis indicates that the climate was
more humid with dry seasons, the thick cuticle, sunken stomata and the papillae surrounding the stomatal
aperture indicate that Scytophyllum karamayense may have suffered from water stress, with the cuticle being
adapted to reducing water loss (He et al., 2017). Generally, the Peltaspermales are therefore xerophytes and
megathermic plants.
5.4.1.13 Pinaceae
The fossils of Pityophyllum have been found in the Haojiagou Formation (Sun et al., 2010a). One pollen
genus Pinuspollenites (Figure 5-3-K, 5-C) that has been proven in the palynomorph assemblage can be
assigned to the family of Pinaceae. Pinuspollenites is comparable with extant pollen of Pinus (Song et al.,
2000).
The Pinaceae, originated at least from Late Triassic, today are principally a Northern Hemisphere,
temperate family and are the largest modern conifer family including shrubs and trees, some up to 100 m tall
(Taylor et al., 2009). Most extant species are trees of generally poor, acidic and either wet or rocky habitats,
sometimes forming mixed evergreen or evergreen broad-leaved forests, but more often forming extensive
monotypic stands over large, north-temperate areas. There are particular concentrations of species in both, North
America and in the east of Asia, with a considerable number of endemic species with more restricted range in
the Sino-Himalayan region. The limited number of species which spread southward in Central America or in SE
Asia, are essentially montane (Kramer and Green, 1990). They are generally mesophytes and microthermic

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plants.
5.4.1.14 Pleuromeiaceae
Fossils of Annalepis and Pleuromeia have been found in the Middle-Late Triassic Karamay Formation in
the region of Northwestern China (Shi et al., 2015). One spore genus Aratrisporites (Figures 5-2-D, 4-C) that
has been recognized in the palynomorph assemblage can be assigned to the family of Pleuromeiaceae.
Aratrisporites is comparable with the in situ spore of Annalepis (Grauvogel-Stamm and Duringer, 1983).
Species of Pleuromeiaceae, an exclusively Triassic family, are mostly herbaceous plants (Taylor et al.,
2009) that lived in extensive mono-dominant thickets perhaps partly submerged in the bays and lakes of delta
systems debouching into coastal lakes, lagoons, or even partly in the water bodies of desert oases (Retallack,
1975; Wang and Wang, 1982). They are widely distributed from low to high palaeolatitudes and are therefore
not sensible to temperature variations (Vakhrameev, 1991). Therefore, they are generally hydrophytes and
eurythermic plants.
5.4.1.15 Sphagnales
One spore genus Sphagnumsporites (Figures 5-3-O, 5-G) that has been found in the palynomorph
assemblage can be assigned to the order of Sphagnales. Sphagnumsporites is identical with the extant spore of
Sphagnum (Potonié, 1956). Sphagnumsporites from the Haojiagou Formation (Figure 5-3-O) is more
comparable with the extant spore of Sphagnum cuspidatum reported by Zhang et al. (2006).
The extant Sphagnaceae are a monogeneric family of peat moss based on the extant genus Sphagnum
(Goffinet and Buck, 2004). Species are nearly cosmopolitan, most of them are found in circumboreal regions in
bogs, wetlands, or swamp forests (Boros et al., 1993; Gao, 1994). They are generally hydrophytes and
eurythermic plants.
Figure 5-6 Pollen diagram of the studied 10 m thick lignite seam of the Haojiagou Formation (see Figure 5-1) showing the abundance of
15 plant orders or families. The zonation is based on constrained cluster analysis using the unweighted pair-group average (UPGMA)
method and a Euclidean distance.

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Figure 5-7 Pollen diagram of the studied 10 m thick lignite seam of the Haojiagou Formation (see Figure 5-1) showing the abundance of
5 Eco-Plant groups that assess the effect of humidity and the effect of temperature. The zonation is based on constrained cluster analysis
of the abundance of 15 plant orders or families presented in Figure 5-6.
5.4.2 Quantitative analysis
The abundance diagrams of plant orders/families (Figure 5-6) and Eco-Plant (Figure 5-7) show that
several taxa vary significantly in frequency throughout the studied section. Based on constrained cluster analysis
five palynozones (PZ) can be recognized. They are characterized by distinct palynomorph assemblages.
5.4.2.1 Palynozone PZ 1
The 8 samples HJG_01 to HJG_08 can be assigned to PZ 1. The zone is generally characterized by the
high abundances of pollen for the Corystospermales with an average value of 39.6% (Figure 5-6). It shows an
increase in abundance from the base to the top of the zone. While at the base a value of 25% is reached, the
values increase up to 63.8% in sample HJG_08. Other common elements in PZ 1 are the pollen of the
Bennettitales (12.3% on average) and Ginkgoales (8.7% on average) as well as the spores of the Gleicheniales
(10.3% on average). Only the Bennettitales achieve their maximum in the entire succession with 33.8% in
HJG_01.
Less frequently and with decreasing values from the base to the top of the PZ other spores such as those
of Cyatheales and Marattiales begin to appear. The Marattiales in sample HJG_02 reach 11.3% and thus the
second highest value in the whole succession; whereas, in sample HJG_08 they occur with only 1.8%. The
spores of the Cyatheales, in HJG_01 with a value of 6.6%, disappear completely at the top of the PZ.
However, the most striking feature of PZ 1 is the appearance of pollen of the Cheirolepidiaceae, which are
represented at the base of the PZ with only 1.5%. Subsequently, the values increase up to 29.1%, but decrease to
0.9% towards the top of the PZ. Nonetheless, the pollen of these conifers is almost exclusively restricted to PZ 1
and appear in the succeeding PZs only with single pollen grains in the palynomorph assemblages. In the PCA of
plant orders/families (Figure 5-8), PZ 1 is due to the occurrence of the Cheirolepidiaceae, clearly separated

87
from the other PZs. The samples plot in the upper left corner of the ordination space with a small overlap with
PZ 3.
Due to the high abundances of plants such as the Cheirolepidiaceae and Corystospermales among the EPT
the megathermic plants and among the EPH the mesophytes and xerophytes are the prevailing Eco-Plant groups.
Between 68.7% and 89.9% of the palynomorphs belong to megathermic plants with an average abundance of
79.9%, while between 39.8% and 86.3% are mesophytes with an average abundance of 60.3%. The xerophytes
reach their maximum within the succession in PZ 1. Due to the high values of megathermic plants and
xerophytes, the samples of PZ 1 are also separated from most other samples in the PCA of the Eco-Plant and
plot at the negative side of PCA axis 2 (Figure 5-9).
Figure 5-8 Principal Component Analysis of the plant order/family data set showing the biplot of the first two axes.
Note: A. Scatter plot of the first two axes (19.49/17.84% variance) showing the arrangement of samples. The different colors represent
samples from different palynozones; B. Scatter plot of the first two PCA axes showing the arrangement of taxa. The dots show the
arrangement of samples (see view Figure 5-8-A).

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Figure 5-9 Principal Component Analysis of the Eco Plant data set showing the biplot of the first two axes.
Note: A. Scatter plot of the first two axes (34.33/29.04% variance) showing the arrangement of samples. The different colors represent
samples from different palynozones; B. Scatter plot of the first two PCA axes showing the arrangement of Eco Plant groups. The dots
show the arrangement of samples (see view Figure 5-9-A).
5.4.2.2 Palynozone PZ 2
This zone is composed of only two samples (HJG_09, HJG_10), which, have a significantly different
composition of the palynomorph assemblages compared to all other PZs (Figure 5-6). Therefore, the two
samples are clearly separated from all other samples in the PCA of the plant orders/families and plot in the
lower right corner of the ordination space (Figure 5-8). The separation is due to a significant increase in pollen
from the Ginkgoales and Bennettitales. The Ginkgoales reach their maximum in the entire succession with
values of more than 41% in the two samples. Compared to PZ 1, the increase of pollen of the Bennettitales up to
22.9% is significant. Accordingly, beside the mass occurrence in the basal sample, the second highest value for
the entire succession is reached.
In contrast, the strong decrease of pollen of the Corystospermales from 63.8% in PZ 1 to 11.7% in PZ 2 is
distinctive. The pollen of the Cheirolepidiaceae, which are common elements in PZ 1, completely disappears in
PZ 2. All other taxa remain nearly unchanged in their abundance compared to PZ 1.
With the strong increase of the Ginkgoales, there is a strong abundance change in the dominance of the
Eco-Plant (Figure 5-7). After the occurrence of xerophytes in PZ 1, mesophytes become increasingly dominant
among the EPH with an average abundance of 76.2%. Also among the EPT, there is a clear change represented

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by the significant increase of mesothermic plants with an average abundance of 43.1%. At the same time the
proportion of megathermic plants decreases significantly from 86.3% at the top of PZ 1 to 49.3% in PZ 2 with
an average abundance of 49.6%. The PCA of the Eco-Plant illustrates this strong change, since PZ 2 is plotted at
the positive end of PCA axis 2 and thus opposite to the samples of PZ 1, which are on the negative end of the
axis (Figure 5-9).
5.4.2.3 Palynozone PZ 3
A total of 11 samples from the central part of the studied succession are included in PZ 3 (HJG_11 to
HJG_25). In the PCA of the plant orders/families, the samples are plotted at the centre of the ordination space
separated from most of the samples of the other PZ (Figure 5-8). PZ 3 is again characterized by the high
abundances of pollen from the Corystospermales, which appear with strong frequency fluctuations.
Nevertheless, a superimposed gradual increase up to 52.5% to the top of PZ 3 is recognizable. In addition to the
Corystospermales, the pollen of the Ginkgoales is also widespread. However, by reaching only a maximum of
34.8%, the abundance is decreased compared to PZ 2. The pollen of the Bennettitales as well as the spores of
the Gleicheniales are represented with consistently high values of more than 10% in PZ 3.
After the decline at the top of PZ 1 and the almost complete absence in PZ 2, the spores of tree ferns of
the Cyatheales and also the spores of the Marattiales increase again. The values for the Cyatheales increase
continuously to the top of PZ 3 to more than 5%, while the Marattiales show up with 12.9% which is their
maximum for the entire succession.
Among the Eco-Plant, the mesophytes with an average abundance of 64.8% dominated the EPH due to
the common abundance of Corystospermales and Ginkgoales. In almost all samples values of more than 57%
are reached which is intermediate between PZ 1 and PZ 2. Among the EPT the megathermic plants are
prevailing and reach between 53.5% and 79.7% with an average abundance of 69.4%. In addition to a clear
separation of PZ 2 and PZ 3, the PCA of the Eco-Plant also shows a separation to the samples of PZ 1, but with
a small overlapping area (Figure 5-9).
5.4.2.4 Palynozone PZ 4
The 4 samples HJG_26 to HJG_30 can be assigned to PZ 4. In the PCA of plant orders/families the
samples are plotted at the positive side of PCA axis 1 and are thus clearly separated from the other samples
(Figure 5-8). PZ 4 is characterized in particular by the strong propagation of fern spores of the Cyatheales and
Gleicheniales. The Cyatheales, which already show increasing values in PZ 3, now reach their maximum for the
complete succession with up to 17.7%. The Gleicheniales also show their overall maximum with 33.9%.
Due to the increasing values for the Gleicheniales, the mesophytes are still the dominant elements among
the EPH with an average value of 60.6%, but the hygrophytes still show a significant increase compared to PZ
3. Among the EPT, the megathermic plants are still the most abundant elements with an average value of
68.3%. Therefore, in the PCA of Eco Plant (Figure 5-9), PZ 4 is, together with samples of PZ 5c, separated
from the other zones especially due to the higher values of hygrophytes.
5.4.2.5 Palynozone PZ 5
The 5 samples HJG_33 to HJG_37 can be assigned to PZ 5. However, due to strong abundance changes
of some taxa, PZ 5 can further be subdivided in three subzones PZ 5a (samples HJG_33-34), 5b (sample
HJG_35) and 5c (samples HJG_36-37). In the PCA of plant orders/families (Figure 5-8) the two samples of PZ
5a are plotted together with the samples of PZ 3 in the centre of the ordination space. PZ 5b is plotted at the
negative end of PCA axis 2, distinctly separated from the other samples of the succession, whereas the two
samples of PZ 5c can be found in the upper right corner of the ordination space in the area of PZ 4.
In PZ 5a the values for the spores of the Cyatheales and Gleicheniales, which showed their peak
abundance in the preceding PZ 4, clearly decline. Instead, the pollen of the Corystospermales is once again
characterized by high abundances. Additionally, the spores of the Pleuromeiaceae occur with a significant

90
increase and reach 10.2% in PZ 5a. In the succeeding PZ 5b, these spores show, with 34.4%, their main
distribution; however, they disappear nearly completely in PZ 5c. Instead, spores of the Sphagnales appear with
values up to 4.5%.
Among the Eco-Plant, the composition in PZ 5a does not change much compared to PZs 3 and 4.
Accordingly, PZ 5a is plotted in the PCA (Figure 5-9) together with samples of PZ 3 in the centre of the
ordination space. Due to the high abundance of Pleuromeiaceae, the proportion of hydrophytes among the EPH
increase to more than 10% in PZ 5a and to 34% in PZ 5b. This leads to a significant separation of PZ 5b in the
PCA, since sample HJG_35 is plotted in the upper right corner far away from all other samples (Figure 5-9).
With the decreasing number of hydrophytes but due to the relatively high abundance of Sphagnales, PZ 5c is
separated from the other samples of PZ 5 in the PCA and shows similarities to samples of PZ 4.
5.5. Discussion
5.5.1 Palaeoenvironment and Palaeoclimate
In our record of the lignite (10 m in thickness), 19 sporomorph genera have been recognized, which are
abundant and can be presented in the pollen diagram. We found most of the genera reported by Ashraf et al.
(1999; 2010; 2001). However, most genera reported in Lu and Deng (2005) and Huang (2006) are missing. This
is probably due to the fact that we studied with 10 m, only a small section of the 290 m thick whole Haojiagou
Formation. Therefore, the number of 19 genera recognized in the studied lignite seam of the Haojiagou
Formation seems to be representative only for a short section within the complete formation and a specific
environment. However, in both studies, many genera have been described whose abundances are generally less
than 2% (Huang, 2006; Lu and Deng, 2005). Related to the entire Haojiagou Formation, these taxa are
extremely rare and often disappear. For our purpose, they play only a minor role in presenting general
statements on the composition of the vegetation and the interpretation, e.g., of the climatic conditions. The
number of 19 genera, which are generally common in the Haojiagou Formation, may therefore also be
representative for predicting the overall composition of the vegetation in the entire formation.
The palynological samples of the Haojiagou Formation belong to the Concavisporites-Duplexisporites
problematicus-Ricciisporites tuberculatus zone, which has been shown repeatedly in Iran, Afghanistan and
Germany indicating that all these basins belong to the same phytogeographic province (Ashraf et al., 1999;
Ashraf et al., 2010; Ashraf et al., 2001). However, the Corystospermales are a relatively small group of plants
which have a primarily Gondwanan distribution and are known from Triassic localities in Antarctica, South
Africa, Australia, Argentina, Tasmania, and India (Artabe and Brea, 2003; Taylor et al., 2009). The discovery of
the plant fossil Thinnfeldia by Sun et al. (2010a) and the high abundance of pollen related to the
Corystospermales indicate that the Haojiagou flora is also associated with the Gondwanan flora of the Late
Triassic. The palynological samples of the Haojiagou Formation also belong to the Concavisporites-
Dictyophyllidites-Chasmatosporites-Cycadopites assemblage, which is comparable to the Late Triassic
palynological assemblage of the Ipswich Coalfield of Australia (Huang, 2006). Therefore, it can be estimated
that the Late Triassic Haojiagou flora is a mixed flora with both Eurasian and Gondwanan elements.
Generally, the 5 pollen zones, which can be distinguished by cluster analysis and NMDS, are qualitatively
very similar in composition. However, there are significant quantitative changes within the palynomorph
assemblages. Since all samples are taken from lignites of the coal-bearing part of the Haojiagou Formation they
reflect a similar depositional environment. Although the coal-bearing part is intercalated with an about 1 m thick
sandy bed (Figure 5-1-C), the bed is laterally not continuous. All the samples are taken from the continuous
coal-bearing part (Figure 5-1-D). There is no lithofacies change for the sampled coal-bearing part. The type of
vegetation is governed by two principal controls: sea (lake)-level fluctuations and climate (Abbink et al.,
2004b). However, sedimentary study reveals that there are no significant lake-level fluctuations for the sampled
coal-bearing part (Hornung and Hinderer, 2011). Therefore, quantitative changes within the palynomorph
assemblages may probably point to climate changes. The Eco-Plant model depicts and confirms these climate
trends in high resolution. Thus, the pollen zones reveal the evolution of vegetation and climate during the
deposition of the lignite deposits of the Haojiagou Formation in 5 phases.

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Figure 5-10 Reconstruction of the palaeoenvironment and vegetation for the Late Triassic Rhaetian (Haojiagou Formation) based on this
study and the Early Jurassic Hettangian (basal Badaowan Formation) after Lu and Deng (2005). The area of water indicates the relative
humidity and the size of the sun indicates the relative temperature. Due to low abundance, the plants of Pinaceae are not depicted.

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5.5.1.1 Warm and dry/wet subtropical phase 1 (Palynozone 1)
The palynomorph assemblage in PZ 1 (Figure 5-10-A) reflects the driest and hottest conditions among all
PZs, since it is characterized by the highest average abundance of megathermic plants and highest average
abundance of xerophytes. The flora is mainly composted by plants of Corystospermales, Bennettitales, and
Gleicheniales (Figure 5-6).
As shrubs or trees, Corystospermales and Bennettitales were elements of the canopy and sub-canopy
vegetation. The shrubs or trees of Cheirolepidiaceae are almost exclusively distributed in this PZ. Extant
Gleicheniales are heliophilous terrestrial ferns which are today distributed under the forest canopy. The
heliophilous trait and high abundance of the Gleicheniales may therefore indicate that the forest canopy was not
dense, and sunlight frequently reached the forest floor. This is also confirmed by the appearance of the
Cyatheales, which often occur in the undergrowth of moist forests or open habitats (Kramer and Green, 1990).
Therefore, an open vegetation was widespread in the vicinity of the peat-forming swamps (Figure 5-10-A).
Corystospermales, Bennettitales, and Gleicheniales are all megathermic plants. Furthermore, the ferns of
the Marattiales, which reach their maximum in PZ 1, occur exclusively in tropical and subtropical regions
(Kramer and Green, 1990). Extant species of Cyatheales are tree ferns concentrated in the tropics (Kramer and
Green, 1990). The dominant megathermic plants point therefore to a tropical or subtropical climate. However,
Mesozoic ginkgoalean plant fossils are found widely in fossil records, except at the Equator and in Antarctica
(Wang et al., 2017). The considerable abundances of Ginkgoales together with the high abundance of the
megathermic plants indicate that the climate condition during the deposition of PZ 1 was more subtropical than
tropical. This is confirmed by Triassic palaeolatitudes of this region between 23.3° N to 31.1° N (Li et al.,
1999).
Due to the high abundance of Cheirolepidiaceae pollen, which is nearly restricted to PZ 1, the xerophytes
show a high average abundance of 9.9% with peak values up to 30.5%. Nevertheless, hygrophytes also occur in
this zone with an average of 26.4 % and peak values up to 47%, which are more common than the xerophytes.
Therefore, a climate with both drought and wet periods is indicated. This can explain that fibre coal is
particularly common in the lignite deposits which was formed almost exclusively by forest fires (Hornung and
Hinderer, 2011; Ligouis, 2001). However, the abundant mesophytes such as the ferns of the Gleicheniales could
not resist long term drought and show that the drought periods may have occurred often but were apparently
short. Also, the extant species of Cyatheales cannot resist long periods of drought as tree ferns in the
undergrowth of moist forests (Kramer and Green, 1990). Therefore, wet periods may have been longer than
drought periods.
The hygrophytes decrease throughout PZ 1, whereas mesophytes increase to the top of PZ 1. This
indicates an overall change of the climate that climaxed in the succeeding PZ 2.
5.5.1.2 Cooler subtropical phase 2 (Palynozone 2)
In the short phase represented by the two samples of PZ 2, the strong increase of pollen of Bennettitales
and Ginkgoales is noteworthy (Figure 5-10-B). This indicates a quantitative change in the composition of the
forest. However, the flora is mainly composed by plants of Ginkgoales and Corystospermales. The average
abundance of Ginkgoales is higher than that of Corystospermales. During the Mesozoic, plants of the
Ginkgoales were associated with plants that were adapted to different climates ranging from hot and dry, to wet
and temperate in coastal plain and lowland to inland riparian/swamp environments (Zhou, 2009). However, as
mesothermic plants, they preferred mesic habitats in temperate regions in mixed conifer-broadleaved forests
(Kramer and Green, 1990). Therefore, the abundant pollen of the Ginkgoales may indicate a climate change to
slightly cooler temperatures during PZ 2. This is also confirmed by the strong decrease of megathermic plants
such as the Cheirolepidiaceae and the ferns of the Marattiales, which both completely disappear in PZ 2.
The average abundance of megathermic plants such as the Corystospermales significantly decreased in PZ
2. The increase of deciduous trees such as the Ginkgoales therefore indicates a cooler climate with strong
seasonality (Kramer and Green, 1990; Zhou, 2009). Although mesothermic plants had their highest average

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abundance in PZ 2, they did not reach the values of megathermic plants. It can be inferred that the climate of PZ
2 is still subtropical with the MAT above 20 °C, but the MAT is probably lower compared to PZ 1.
5.5.1.3 Subtropical phase 3 (Palynozone 3)
The change in the composition of the floras between PZ 1 and PZ 2 is followed by a further change within
the vegetation during PZ 3 (Figure 5-10-C). The flora is mainly composed by the plants of Corystospermales,
Ginkgoales, and Bennettitales. The Corystospermales gradually increase, indicated by the increasing values of
their pollen within PZ 3. Along with this, the values for the Bennettitales and Ginkgoales are gradually
decreasing from the base to the top of PZ 3. However, both plant orders are more abundant compared to most
parts of PZ 1 indicating that they were important parts of the vegetation during PZ 3. The gradual appearance of
the tree ferns of the Cyatheales is also notable. Other ferns such as the Gleicheniales, which have the highest
abundance among all ferns within the flora, or Osmundales and Marattiales, are relatively common and point to
an open forest community.
The frequency trends of the palynomorphs, such as the increase of pollen of the Corystospermales or the
decrease of pollen of the Ginkgoales indicate a gradual warming. The temperature-related Eco-Plant model
clearly reveals this trend, because the megathermic plants are generally dominant. However, the opposite
abundance trends of Corystospermales and Bennettitales pollen (megathermic plants) show that besides a
temperature increase, humidity changes may have also had an influence on the composition of the vegetation.
In general, due to the dominance of the megathermic plants, a subtropical climate is indicated during the
deposition of PZ 3. However, the values for the megathermic plants are not as high as in PZ 1. On the other
hand, the proportions of the mesothermic plants in PZ 3 are significantly higher than in PZ 1. Therefore, the
high temperatures that have occurred during PZ 1 are probably not reached in PZ 3. Nevertheless, they were
higher than during PZ 2. In conclusion, a MAT of c. 20 °C can be assumed.
During PZ 3 hygrophytes reach higher values than in PZ 2, indicating that PZ 3 was more humid than PZ
2. However, the dominant mesophytes, such as the Ginkgoales, also point to strong seasonality and less humid
periods during the season.
5.5.1.4 Subtropical phase 4 (Palynozone 4)
The vegetation during PZ 4 is still dominated by plants of Ginkgoales and Corystospermales.
Furthermore, the PZ is characterized by the increased occurrence of spores of the Cyatheales and the
Gleicheniales (Figure 5-10-D). This may indicate increasingly open habitats. In particular, the tree ferns of the
Cyatheales are widespread within the vegetation of PZ 4. Therefore, the abundance trend among these ferns,
which has already started with the gradual increase of values within PZ 3, continues. As hygrophytes, which
cannot resist longer periods of draught, they point to increasingly humid conditions.
The values for megathermic and mesothermic plants are nearly unchanged compared to their occurrence
in PZ 3. Therefore, they point still to very warm temperatures and subtropical climate with a MAT above 20 °C.
5.5.1.5 Wet subtropical phase 5 (Palynozone 5)
During PZ 5, the forest is dominated by plants of Gleicheniales, Ginkgoales, and Corystospermales.
However, the palaeoenvironmental changes in the depositional area are strengthened, as indicated by strong
frequency fluctuations within the palynomorph assemblages (Figure 5-10-E), which leads to the separation of
PZ 5 into three sub-zones. Principally, the common occurrence of hydrophytes points to increasingly humid
conditions during the deposition of PZ 5 with a rising water level or increasing areas with open water that were
settled by submerged plants such as the Pleuromeiaceae. In PZ 5 they appear with higher values, but peaked in
PZ 5b. The Pleuromeiaceae are replaced in PZ 5c by the Sphagnales. The modern Sphagnum (peat moss) is the
dominant plant type in modern ombrotrophic bogs and adapted to acidic, waterlogged and nutrient-limited
environments (Clymo, 1984; van Breemen, 1995). The Sphagnum-type spores that can be found in the
Haojiagou Formation thus indicate significant changes in the local hydrology and nutrient conditions. Modern

94
Sphagnum is an important plant of raised bogs indicating the end of lignite deposition (Inglis et al., 2015). In the
studied seam of the Haojiagou Formation an ombrogenous peat bog maintained by growth of Sphagnales had
been formed in association with a variety of ferns such as those of the Gleicheniales and Cyatheales. In
conclusion, during PZ 5, changes in hydrological conditions (e.g., by increased precipitation) are responsible for
changes within the vegetation and less changes in temperature.
The dominance of megathermic plants such as the Corystospermales indicates persistently very warm
temperatures and a MAT above 20 °C. However, the decreasing values for the megathermic plants in PZ 5b
may point to slightly cooler conditions as in PZ 4.
5.5.2 The Triassic/Jurassic boundary
The Triassic-Jurassic boundary in Northwestern China is characterized by the disappearance of the marker
taxa of Aratrisporites, Chordasporites, Taeniaesporites and Bharadwajapollenites, which occur at the base of
the Lower Jurassic Badaowan Formation in this section (Ashraf et al., 2010; Lu and Deng, 2005). They
separately represent Bennettitales (Bharadwajapollenites), Peltaspermales (Chordasporites and
Taeniaesporites), and Pleuromeiaceae (Aratrisporites). Plants of the Bennettitales were distributed from the
Triassic to the Cretaceous in both hemispheres (Taylor et al., 2009). Densoisporites related with Pleuromeiaceae
has been discovered at the base of the Lower Jurassic Badaowan Formation in this section with abundances up
to 46.3% (Lu and Deng, 2009). Peltaspermales were extinct at the Triassic-Jurassic boundary. Classopollis
related with Cheirolepidiaceae was the dominant pollen at the base of the Lower Jurassic Badaowan Formation
(Lu and Deng, 2009). Both, Cheirolepidiaceae and Peltaspermales are xerophytes and megathermic plants. In
the studied lignite bed of the Haojiagou Formation, which are considerably below the Triassic-Jurassic
boundary, the abundances of Peltaspermales are already rare (<6.4%). Hence, it may be estimated that the
Peltaspermales were replaced by Cheirolepidiaceae during the Late Triassic by slow competition rather than
sudden disaster.
Pollen percentages are influenced by both, different pollen production within a genus, and by differences
in the relative pollen production of taxa within different vegetation assemblages. Nevertheless, data on the
relative abundances of different taxa of pollen in present day surface sediments of eastern North America can be
compared directly with forestry data on the abundance of trees of the same species in forests close to the surface
sediment sources (Delcourt and Delcourt, 1985). Based on the low pollen abundance of Peltaspermales, it can
be estimated that the abundances of these plants in the Haojiagou flora were also low. In comparison, the pollen
abundance of Cheirolepidiaceae in the sampled lignite bed can reach up to 29.1%.
Although among the 15 plant orders and families that were distributed throughout the studied part of the
Haojiagou Formation, 14 of them passed the Triassic-Jurassic boundary; their abundances changed
significantly. Different authors separately reported that changes in the abundance of pollen and spores in the
Haojiagou Formation are relatively gentle, but significant at the Triassic-Jurassic boundary (Ashraf et al., 2010;
Lu and Deng, 2009). The generally similar values of δ13 Corg for the whole Haojiagou Formation indicate that
there was no significant climate change (Lu and Deng, 2009). In this case, the studied samples taken from
lignites of the coal-bearing part of the Haojiagou Formation, can also give an overall view on the palaeoclimate
of the whole Haojiagou Formation, although detailed palynological study for the whole formation is still
needed. Although some fluctuations in humidity and temperature are indicated, the five palynozones generally
reveal a variable, but general subtropical climate with seasonal changes of both wet and drought periods. The
drought periods were shorter compared to the wet periods.
A spike in the abundance of fern spores, mainly composed by Cyathidites (54.9%) and Deltoidospora
(7%), in the basal Badaowan Formation (Hettangian) in the studied section has been reported by Lu and Deng
(2005, 2009). The high abundance of Cyathidites and the very low abundance of Cycadopites (7. 1%) in the
Badaowan flora indicates that the Late Triassic shrub and tree forests, as revealed in the Haojiagou flora with a
dominance of Bennettitales, Cheirolepidiaceae, Corystospermales, Ginkgoales, and Peltaspermales were
replaced by a flora dominated by tree ferns of Cyatheales in the Early Jurassic (Figure 5-10-F). The deciduous
trees such as the Ginkgoales indicate a cooler climate with strong seasonality during the late Triassic (Kramer
and Green, 1990; Zhou, 2009). The increase of hygrophytes and megathermic plants such as Cyatheales and the

95
decrease of the mesothermic plants such as the Ginkgoales indicate that the climate of the basal Badaowan
Formation of the Early Jurassic (Hettangian) was much hotter and wetter than in the Late Triassic (Rhaetian). In
addition, it may be inferred, that the seasonal change in the basal Badaowan Formation of the Early Jurassic
(Hettangian) was not remarkable. In the layer of the fern spore spike in the Badaowan Formation, the significant
negative deviation of δ13 Corg to a value lower than the regular value of 24.5‰ also indicates a change to a much
hotter and wetter climate (Lu and Deng, 2009).
The strong climate change between the Late Triassic (Rhaetian) and the Early Jurassic (Hettangian) is also
confirmed by the fact that huge and economically important lignite seams together with Fe-rich (especially
ironstone rich) sediments occur in the basal Badaowan Formation. As the lignite beds in the Haojiagou
Formation are generally relatively thin, the occurrence of thick lignite seams in the Badaowan Formation point
to warmer and probably even more humid conditions during the Early Jurassic which is favorable for the long-
lasting growth of a peat-forming vegetation (Ashraf et al., 2010).
The abundance spike in fern spores across the Triassic/Jurassic boundary has also been found in
Greenland, northern France, northeastern US, southern Spain, and Austria (Heunisch et al., 2010; van de
Schootbrugge et al., 2009), was also found to be related to changes in climate, such as increasing global
temperatures and humidity (Michalik et al., 2010). It can be concluded that the climate change across the
Triassic/Jurassic boundary in Haojiagou section is part of the global climate change event.
5.6 Conclusions
This study presents the first detailed high-resolution palynoflora and vegetation patterns of a 10 m thick
lignite seam from the Late Triassic terrestrial Haojiagou Formation (Rhaetian). It revealed 5 palynozones each
characterized by specific palynomorph assemblages that indicate changes within peat forming vegetation. At the
beginning of peat formation, plants of the Cheirolepidiaceae and the Corystospermales, and to a lesser extent
plants of the Bennettitales, Ginkgoales and Peltaspermales, formed the forest canopy in the depositional area;
whereas, ferns of the Gleicheniales and Cyatheales, inhabited the forest floors and open habitats. The plants
point to a subtropical climate. Later the increase of pollen of the Ginkgoales indicates stronger seasonality and a
climate change to cooler conditions, but still with a predominantly subtropical climate. At the end of peat
formation a shift to more humid conditions can be noticed. The overall climate was subtropical with seasonal
changes of both wet and drought periods. The drought periods were shorter compared to the wet periods. The
overall trend to a wetter climate is proven by the changes in abundance of xerophytes, hygrophytes, and
hydrophytes. However, the distribution of spores of the Sphagnales shows that not only climate change was
responsible for changes within the vegetation, but also hydrological conditions and the availability of nutrients.
Compared to the following Lower Jurassic Badaowan Formation (Hettangian), the strong changes in the
composition of the vegetation indicate that the climate was much hotter and wetter in the region than in the Late
Triassic, which mimics the global signal.
The use of the Eco-Plant model that assesses the effect of humidity as well as the effect of temperature
turned out to be an important tool for revealing climate variations in the record. In general, the model analyzes
diverse plant associations in relation to their principal habitat preferences with high sensitivity. Hence, the
model is also a suitable method for other Mesozoic microfloras which do not show a major turnover in species
composition within their palynomorph assemblages. However, for robust palaeoenvironmental analyses using
the Eco-plant model, the accurate identification of parent plants is required, which is more problematic the older
the record is. This was done with a combination of LM and SEM that allowed the assignment of 18 out of 19
recognized palynomorph genera to their parent plant orders and genera, which was assisted by our online
database Sporopollen (http://www.sporopollen.com). In conclusion, to get a precise affinity and Eco-Plant,
detailed SEM studies are crucial.
In view of the rarity of similar studies of terrestrial records from the Mesozoic basins in Northwestern
China, this study should be seen as an initial step in the recognition of palaeoecological and climatic variations
during this period. Therefore, it is necessary to identify and study more terrestrial records in higher resolution to
get a deeper insight into the dynamics and controls of palaeoenvironmental changes.

96

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6. Summary
The new database Sporopollen (http://www.sporopollen.com) focused mainly on Mesozoic sporomorphs is
created. Currently, it has collected 100,610 sporomorph pictures, 59, 498 plant pictures, 31, 922 sporomorph
descriptions. At the same time, from 63, 035 references, it has collected 2, 215, 162 occurrences for both
sporomorph and non-sporomorph fossils. The collected plant data include 32, 972 genera from 946 families.
The collected sporomorph pictures include 5, 857 genera. They can be queried in the form of a map or dataset. It
collects illustrations, descriptions, occurrences, and the taxonomy of sporomorphs. Different user-friendly
interfaces are created for:
 Data query both on a map and in datasets
 Sporomorph identification
 Stratigraphic analysis
 Linking sporomorphs to their parent plants
With the help of the database, based on literature and the unique outline and structure/sculpture of the
sporomorph wall, 861 dispersed Mesozoic sporomorph genera of Bryophytes, Pteridophytes, and Gymnosperms
are reviewed by comparing the unique outline and structure/sculpture of the sporomorph wall with that of
modern plants and in situ fossil plants. 474 of them can be linked to their closest parent plants and Eco-Plant
model at family or order level. 387 of them can not because of the lack of detailed ultrastructure descriptions.
The presented eco-groups for dispersed Mesozoic sporomorphs provide the possibility to identify the detailed
plant and palaeoenvironmental change in the Mesozoic, especially in the context of climate change. We can also
get the following conclusions:
 The use of LM for determination is one of the main reasons that some dispersed sporomorphs
cannot be linked precisely to their parent plants.
 In the Mesozoic, both spore-producing plants and pollen-producing plants are adapted to different
kinds of humidity.
 The concept to use the spore/pollen ratio to reflect the hygrophytes/xerophytes ratio is
questionable.
A new interface (http://www.sporopollen.com/sporemesozoicsegs.php?opencode=paper1) was created
based on the reviewed result to quickly link the dispersed sporomorphs to past vegetation patterns and climatic
changes. Users can upload their data to the database and in return get quick results. It can automatically link all
of the Mesozoic and Cenozoic sporomorphs to their possible parent plants at phylum, order, or family level. It
can also automatically link all of the Triassic and Jurassic sporomorphs to the Eco-Plant model to assess the
effect of humidity (EPH) and the effect of temperature (EPT). The new interface is:
 A useful tool for using the Eco-Plant model to reconstruct Triassic and Jurassic humidity and
temperature.
 A useful tool for palaeoenvironmental reconstruction.
 A useful tool for high-resolution quantitative palynomorph study.
As a case study, the Eco-Plant model and the sporomorphs of a 10 m thick lignite bed from the Upper
Triassic Haojiagou Formation (Rhaetian) are used to discuss the palaeovegetation and palaeoenvironment of a
peat-forming wetland near the Triassic-Jurassic boundary. The result shows that the palynoflora contains both
Eurasian and Gondwanan elements, and is dominated by the spores and pollen of Bennettitales,
Corystospermales, Ginkgoales, and Gleicheniales. At the Triassic/Jurassic boundary (Hettangian), the

98
palynoflora significantly changes as Cyatheales spores become the dominant elements. We analyse assemblages
in terms of an Eco-Plant model, which assigns the parent plants of the palynomorphs into five groups based on
humidity and four groups based on temperature, and uses multivariate statistical analyses to infer palaeoclimate
and palaeoenvironmental conditions. Results suggest that the palaeoclimate of the Rhaetian was generally wet
and subtropical with short seasonal drought periods. Our analysis shows that an Eco-Plant model may be a
useful tool to reveal past vegetation patterns and climate changes, applicable to other Mesozoic assemblages.

99
References
Abbink, O., Targarona, J., Brinkhuis, H., and Visscher, H., 2001, Late Jurassic to earliest Cretaceous
palaeoclimatic evolution of the southern North Sea: Global and Planetary Change, v. 30, p. 231-256.
Abbink, O.A., Van Konijnenburg-Van Cittert, J.H.A., Van der Zwan, C.J., and Visscher, H., 2004a, A
sporomorph ecogroup model for the Northwest European Jurassic Lower Cretaceous II : Application to
an exploration well from the Dutch North Sea: Netherlands Journal of Geosciences-Geologie En
Mijnbouw, v. 83, p. 81-91.
Abbink, O.A., Van Konijnenburg-Van Cittert, J.H.A., and Visscher, H., 2004b, A sporomorph ecogroup model
for the Northwest European Jurassic - Lower Cretaceousi: concepts and framework: Netherlands
Journal of Geosciences-Geologie En Mijnbouw, v. 83, p. 17-31.
Abu Hamad, A., Kerp, H., Voerding, B., and Bandel, K., 2008, A late Permian flora with Dicroidium from the
Dead Sea region, Jordan: Review of Palaeobotany and Palynology, v. 149, p. 85-130.
Alvin, K.L., 1982, Cheirolepidiaceae - Biology, Structure and Paleo-Ecology: Review of Palaeobotany and
Palynology, v. 37, p. 71-98.
Ames, H.T., and Spackman, W., 1981, Catalog of fossil spores and pollen Volume 42: Cretaceous Spores and
Pollen from the U.S.A. and the U.S.S.R. , University Park, Pennsylvania.
—, 1985, Catalog of fossil spores and pollen Volume 44: Tertiary and Upper Cretaceous Spores and Pollen
from Africa, Europe, Canada, Australia and New Zealand, University Park, Pennsylvania.
Ames, H.T., Traverse, A., and Spackman, W., 1976, Catalog of fossil spores and pollen Volume 40: Triassic -
Cretaceous Spores and Pollen, University Park, Pennsylvania.
Aranbarri, J., Gonzalez-Samperiz, P., Valero-Garces, B., Moreno, A., Gil-Romera, G., Sevilla-Callejo, M.,
Garcia-Prieto, E., Di Rita, F., Mata, M.P., Morellon, M., Magri, D., Rodriguez-Lazaro, J., and Carrion,
J.S., 2014, Rapid climatic changes and resilient vegetation during the Lateglacial and Holocene in a
continental region of south-western Europe: Global and Planetary Change, v. 114, p. 50-65.
Archangelsky, A., Phipps, C.J., Taylor, T.N., and Taylor, E.L., 1999, Paleoazolla, a new heterosporous fern
from the Upper Cretaceous of Argentina: American Journal of Botany, v. 86, p. 1200-1206.
Archangelsky, S., 1966, New gymnosperms from the Ticó flora, Santa Cruz Province, Argentina: Bulletin of the
British Museum (Natural History), Geology, v. 13, p. 259-295.
—, 1994, Comparative ultrastructure of three early cretaceous gymnosperm pollen grains: Araucariacites,
Balmeiopsis and Callialasporites: Review of Palaeobotany and Palynology, v. 83, p. 185-198.
—, 2009, Biogeographic implications of Albian Mohria-like spores (Family Anemiaceae) in SW Gondwana
(Patagonia): Review of Palaeobotany and Palynology, v. 157, p. 301-308.
Archangelsky, S., and Archangelsky, A., 2006, Putative Early Cretaceous pteridaceous spores from the offshore
Austral Basin in Patagonia, Argentina: Cretaceous Research, v. 27, p. 473-486.
Archangelsky, S., and Cuneo, R., 1987, Ferugliocladaceae, a new conifer family from the Permian of Gondwana:
Review of Palaeobotany and Palynology, v. 51, p. 3-30.
Archangelsky, S., and Gamerro, J.C., 1967, Pollen grains found in coniferous cones from the lower cretaceous
of patagonia (Argentina): Review of Palaeobotany and Palynology, v. 5, p. 179-182.
Archangelsky, S., and Seoane, L.V.d., 2005, Estudios palinológicos del Grupo Baqueró (Cretácico Inferior),
provincia de Santa Cruz, Argentina. IX polen bisacado de Podocarpaceae: Revista Española de
Paleontología, v. 20, p. 37-56.
Artabe, A., and Brea, M., 2003, A new approach to Corystospermales based on Triassic permineralized stems
from Argentina: Alcheringa, v. 27, p. 209-229.
Ash, S., 1994, First occurrence of Czekanowskia (Gymnospermae, Czekanowskiales) in the United States:
Review of Palaeobotany and Palynology, v. 81, p. 129-140.
Avramenko, A.S., and Polevova, S.V., 2013, Morphology and ultrasctructure of spores Klukia tyganensis
Krassilov (Schizaeaceae, Filicales) from the Berriassian of the Tyrma Depression (Russian Far East):
Paleontological Journal, v. 47, p. 439-453.
Axsmith, B.J., Krings, M., and Taylor, T.N., 2001, A filmy fern from the upper triassic of North Carolina
(USA): American Journal of Botany, v. 88, p. 1558-1567.

100
Baeza, S., Lezama, F., Pineiro, G., Altesor, A., and Paruelo, J.M., 2010, Spatial variability of above-ground net
primary production in Uruguayan grasslands: a remote sensing approach: Applied Vegetation Science, v.
13, p. 72-85.
Baldoni, A.M., and Taylor, T.N., 1982, The Ultrastructure of Trisaccites Pollen from the Cretaceous of
Southern Argentina: Review of Palaeobotany and Palynology, v. 38, p. 23-33.
Balme, B.E., 1995, Fossil in situ spores and pollen grains: an annotated catalogue: Review of Palaeobotany and
Palynology, v. 87, p. 81-323.
Barale, G., Marron, T.F., and Ramis, C.A., 1988, Étude de cônes mâles de Frenelopsis Schenk
emend.Reymanówna & Watson, 1976 (Cheirolepidiaceae) du Crétacé supérieur de Torrelaguna
(Province de Madrid-Espagne): Geobios, v. 21, p. 187-199.
Barreda, V., Palazzesi, L., and Marenssi, S., 2009, Palynological record of the Paleogene Rio Leona Formation
(southernmost South America): Stratigraphical and paleoenvironmental implications: Review of
Palaeobotany and Palynology, v. 154, p. 22-33.
Bashforth, A.R., Cleal, C.J., Gibling, M.R., Falcon-Lang, H.J., and Miller, R.F., 2014, Paleoecology of Early
Pennsylvanian vegetation on a seasonally dry tropical landscape (Tynemouth Creek Formation, New
Brunswick, Canada): Review of Palaeobotany and Palynology, v. 200, p. 229-263.
Batten, D.J., 2009, An unusual megaspore of uncertain systematic affinity from Lower Cretaceous deposits in
south-east England and its biostratigraphic and palaeoenvironmental significance: Grana, v. 48, p. 270-
280.
—, 2012, Taxonomic implications of exospore structure in selected Mesozoic lycopsid megaspores: Palynology,
v. 36, p. 144-160.
Batten, D.J., and Collinson, M.E., 2001, Revision of species of Minerisporites, Azolla and associated plant
microfossils from deposits of the Upper Palaeocene and Palaeocene/Eocene transition in the
Netherlands, Belgium and the USA: Review of Palaeobotany and Palynology, v. 115, p. 1-32.
Batten, D.J., and Dutta, R.J., 1997, Ultrastructure of exine of gymnospermous pollen grains from Jurassic and
basal Cretaceous deposits in Northwest Europe and implications for botanical relationships: Review of
Palaeobotany and Palynology, v. 99, p. 25-54.
Batten, D.J., and Ferguson, D.J.P., 1987, Cabochonicus, a new genus for species of gemmate megaspores
previously referred to Verrutriletes: Journal of Micropalaeontology, v. 6, p. 65-75.
Batten, D.J., and Koppelhus, E.B., 1993, Morphological Reassessment of Some Zonate and Coronate
Megaspore Genera of Mainly Postpaleozoic Age: Review of Palaeobotany and Palynology, v. 78, p. 19-
40.
Batten, D.J., Zavattieri, A.M., and Collinson, M.E., 2011, Megaspores from the upper Maastrichtian of the
eastern Spanish Pyrenees and their biostratigraphic, palaeogeographic and palaeoenvironmental
significance: Review of Palaeobotany and Palynology, v. 167, p. 156-172.
Bek, J., Oplustil, S., and Drabkova, J., 2001, Two species of Selaginella cones and their spores from the
Bohemian Carboniferous continental basins of the Czech Republic: Review of Palaeobotany and
Palynology, v. 114, p. 57-81.
Bharadwaj, D.C., and Dwivedi, A., 1981, Sporae dispersae of the Barakar sediments from South Karanpura
Coalfield, Bihar, India: Palaeobotanist, v. 21(1), p. 21-94.
Bolchovitina, N.A., 1967, The fossil spores of the family Gleicheniaceae (morphology and taxonomy): Review
of Palaeobotany and Palynology, v. 3, p. 59-64.
Bomfleur, B., and Kerp, H., 2010, Dicroidium diversity in the Upper Triassic of north Victoria Land, East
Antarctica: Review of Palaeobotany and Palynology, v. 160, p. 67-101.
Boros, Á., and Járai-Komlódi, M., 1975, An Atlas of Recent European Moss Spores: Budapest Hungery,
Scientia Publishing.
Boros, Á., Járai-Komlódi, M., Tóth, Z., Nilsson, S., and Pócs, T., 1993, An Atlas of Recent European Moss
Spores, Scientia Publishing, 321 p.
Bozukov, V., Utescher, T., and Ivanov, D., 2009, Late Eocene to early Miocene climate and vegetation of
Bulgaria: Review of Palaeobotany and Palynology, v. 153, p. 360-374.
Brea, M., Artabe, A., and Spalletti, L., 2008, Ecological reconstruction of a mixed Middle Triassic forest from
Argentina: Alcheringa, v. 32, p. 365-393.
Breckon, G.J., and Falk, R.H., 1974, External Spore Morphology and Taxonomic Affinities of Phylloglossum
Drummondii Kunze (Lycopodiaceae): American Journal of Botany, v. 61, p. 481-485.

101
Brenner, G.J., 1963, The spores and pollen of the Potomac Group of Maryland, State of Maryland, Board of
Natural Resources, Department of Geology, Mines, and Water Resources.
Cantrill, D.J., and Webb, J.A., 1998, Permineralized pleuromeid lycopsid remains from the early Triassic
Arcadia formation, Queensland, Australia: Review of Palaeobotany and Palynology, v. 102, p. 189-211.
Cavagnetto, C., and Anadon, P., 1996, Preliminary palynological data on floristic and climatic changes during
the Middle Eocene Early Oligocene of the eastern Ebro Basin, northeast Spain: Review of Palaeobotany
and Palynology, v. 92, p. 281-305.
Césari, S.N., 2006, Aptian ferns with in situ spores from the South Shetland Islands, Antarctica: Review of
Palaeobotany and Palynology, v. 138, p. 227-238.
Césari, S.N., and Colombi, C., 2016, Palynology of the Late Triassic Ischigualasto Formation, Argentina:
Paleoecological and paleogeographic implications: Palaeogeography Palaeoclimatology Palaeoecology,
v. 449, p. 365-384.
Césari, S.N., Panti, C., Pujana, R.R., Francis, J.E., and Marenssi, S.A., 2015, The late Oligocene flora from the
Rio Leona Formation, Argentinian Patagonia: Review of Palaeobotany and Palynology, v. 216, p. 143-
158.
Chambers, T.C., Drinnan, A.N., and McLoughlin, S., 1998, Some morphological features of wollemi pine
(Wollemia nobilis : Araucariaceae) and their comparison to Cretaceous plant fossils: International
Journal of Plant Sciences, v. 159, p. 160-171.
Chantanaorrapint, S., 2015, Taxonomic studies on Thai Anthocerotophyta II. The genus Notothylas
(Notothyladaceae): Cryptogamie Bryologie, v. 36, p. 251-266.
Ching, R.-C., and Shing, K., 1990, Flora of China, Volume 3(1), Science Press (in chinese), 305 p.
Ching, R., 2006, Flora Reipublicae Popularis Sinicae, Volume 2: Beijing, Science Press (in chinese).
Christenhusz, M.J.M., Reveal, J.L., Farjon, A., Gardner, M.F., Mill, R.R., and Chase, M.W., 2011, A new
classification and linear sequence of extant gymnosperms: Phytotaxa, v. 19, p. 55-70.
Clement-Westerhof, J.A., 1984, Aspects of Permian Paleobotany and Palynology .IV. The Conifer Ortiseia
Florin from the Val Gardena Formation of the Dolomites and the Vicentinian Alps (Italy) with Special
Reference to a Revised Concept of the Walchiaceae (Goppert) Schimper: Review of Palaeobotany and
Palynology, v. 41, p. 51-166.
—, 1987, Aspects of permian palaeobotany and palynology, VII. the majonicaceae, a new family of late
permian conifers: Review of Palaeobotany and Palynology, v. 52, p. 375-402.
Clement-Westerhof, J.A., and van Konijnenburg-van Cittert, J.H.A., 1991, Hirmeriella muensteri - New Data on
the Fertile Organs Leading to a Revised Concept of the Cheirolepidiaeae: Review of Palaeobotany and
Palynology, v. 68, p. 147-179.
Collinson, M.E., Batten, D.J., Scott, A.C., and Ayonghe, S.N., 1985, Palaeozoic, Mesozoic and
contemporaneous megaspores from the Tertiary of southern England: indicators of sedimentary
provenance and ancient vegetation: Journal of the Geological Society, v. 142, p. 375-395.
Cottnam, C.F., Hemsley, A.R., Rossler, R., Collinson, M.E., and Brain, A.P.R., 2000, Diversity of exine
structure in Upper Carboniferous (Westphalian) selaginellalean megaspores: Review of Palaeobotany
and Palynology, v. 109, p. 33-44.
Crandall-Stotler, B.J., Stotler, R.E., Doyle, W.T., and Forrest, L.L., 2008, Part Eight: Hornworts Chapter
Nineteen: Phaeoceros proskaueri sp. nov., a New Species of the Phaeoceros hallii (Austin) Prosk.—
Phaeoceros pearsonii (M. Howe) Prosk. Complex and the Systematic Affinities of Paraphymatoceros
Hässel: Fieldiana Botany, p. 213–238.
Crane, P.R., 1996, The fossil history of the gnetales: International Journal of Plant Sciences, v. 157, p. S50-S57.
Cranwell, L.M., and Srivastava, S.K., 2009, An Early Cretaceous (Hauterivian) Spore-Pollen Assemblage from
Southern Chile: Palynology, v. 33, p. 241-280.
De Klerk, P., and Joosten, H., 2007, The difference between pollen types and plant taxa: a plea for clarity and
scientific freedom: E&G Quaternary Sci. J., v. 56, p. 162-171.
de Seoane, L.V., and Archangelsky, S., 2008, Taxonomy and biostratigraphy of Cretaceous megaspores from
Patagonia, Argentina: Cretaceous Research, v. 29, p. 354-372.
Decombeix, A.L., Bomfleur, B., Taylor, E.L., and Taylor, T.N., 2014, New insights into the anatomy,
development, and affinities of corystosperm trees from the Triassic of Antarctica: Review of
Palaeobotany and Palynology, v. 203, p. 22-34.
Del Fueyo, G.M., and Archangelsky, S., 2005, A new araucarian pollen cone with in situ Cyclusphaera Elsik
from the Aptian of Patagonia, Argentina: Cretaceous Research, v. 26, p. 757-768.

102
Deng, S.H., 2002, Ecology of the Early Cretaceous ferns of Northeast China: Review of Palaeobotany and
Palynology, v. 119, p. 93-112.
Dettmann, M.E., 1963, Upper Mesozoic microfloras from South-Eastern Australia: Proceedings of the Royal
Society of Victoria, v. 77, p. 1-148.
Dino, R., Pocknall, D.T., and Dettmann, M.E., 1999, Morphology and ultrastructure of elater-bearing pollen
from the Albian to Cenomanian of Brazil and Ecuador: implications for botanical affinity: Review of
Palaeobotany and Palynology, v. 105, p. 201-235.
Eklund, H., Cantrill, D.J., and Francis, J.E., 2004, Late cretaceous plant mesofossils from Table Nunatak,
Antarctica: Cretaceous Research, v. 25, p. 211-228.
El-Ghazaly, G., Rowley, J., and Hesse, M., 1998, Polarity, aperture condition and germination in pollen grains
of Ephedra (Gnetales): Plant Systematics and Evolution, v. 213, p. 217-231.
Figueiral, I., Mosbrugger, V., Rowe, N.P., Ashraf, A.R., Utescher, T., and Jones, T.P., 1999, The Miocene peat-
forming vegetation of northwestern Germany: an analysis of wood remains and comparison with
previous palynological interpretations: Review of Palaeobotany and Palynology, v. 104, p. 239-266.
Francis, J.E., 1983, The Dominant Conifer of the Jurassic Purbeck Formation, England: Palaeontology, v. 26, p.
277-294.
Friis, E.M., and Pedersen, K.R., 1996, Eucommiitheca hirsuta, a new pollen organ with Eucommiidites pollen
from the early Cretaceous of Portugal: Grana, v. 35, p. 104-112.
Friis, E.M., Pedersen, K.R., and Crane, P.R., 2009, Early Cretaceous Mesofossils from Portugal and Eastern
North America Related to the Bennettitales-Erdtmanithecales-Gnetales Group: American Journal of
Botany, v. 96, p. 252-283.
—, 2014, Welwitschioid diversity in the Early Cretaceous: evidence from fossil seeds with pollen from Portugal
and eastern North America: Grana, v. 53, p. 175-196.
Gao, C., 1994, Flora Bryophytorum Sinicorum Vol.1 Sphagnales Andreaeales Archidiales Dicranales, Science
Press (in chinese), 368 p.
Gao, C., Li, X., Li, Z., Li, P., and Gao, T., 1996, Flora Bryophytarum Sinicorum, Volume 2: Fissidentales
Pottiales Beijing, Science Press (in chinese).
Gastony, G.J., 1982, Spore Morphology in the Dicksoniaceae. II. The Genus Cibotium: Canadian Journal of
Botany-Revue Canadienne De Botanique, v. 60, p. 955-972.
Germeraad, J.H., Hopping, C.A., and Muller, J., 1968, Palynology of Tertiary Sediments from Tropical Areas:
Review of Palaeobotany and Palynology, v. 6, p. 189-+.
Giacosa, J.P.R., Morbelli, M.A., Giudice, G.E., and Gorrer, D.A., 2016, Spore morphology and wall
ultrastructure of Lycopodiaceae from northwest Argentina: Review of Palaeobotany and Palynology, v.
225, p. 84-94.
Glasspool, I., 2000, Megaspores from the Late Permian, Lower Whybrow coal seam, Sydney Basin, Australia:
Review of Palaeobotany and Palynology, v. 110, p. 209-227.
Godin, V.N., 2017, Sexual forms and their ecological correlates of flowering plants in Siberia: Russian Journal
of Ecology, v. 48, p. 433-439.
Goffinet, B., and Buck, W.R., 2004, Systematics of the Bryophyta (Mosses): From molecules to a revised
classification, Molecular Systematics of Bryophytes, Missouri Botanical Garden Press, p. 205-239.
Gomankov, A.V., 2009, Pollen Evolution in Cordaites and Early Conifers: Paleontological Journal, v. 43, p.
1245-1252.
Gosling, W.D., Miller, C.S., and Livingstone, D.A., 2013, Atlas of the tropical West African pollen flora:
Review of Palaeobotany and Palynology, v. 199, p. 1-135.
Grauvogel-Stamm, L., 1993, Pleuromeia sternbergii (Munster) Corda from the Lower Triassic of Germany -
Further Observations and Comparative Morphology of Its Rooting Organ: Review of Palaeobotany and
Palynology, v. 77, p. 185-212.
Grauvogel-Stamm, L., and Duringer, P., 1983, Annalepis zeilleri Fliche 1910 emend., un organe reproducteur
de Lycophyte de la Lettenkohle de l'Est de la France. Morphologie, spores in situ et paléoécologie:
Geologische Rundschau, v. 72, p. 23-51.
Grauvogel-Stamm, L., and Lugardon, B., 2009, Phylogeny and evolution of the horsetails: Evidence from spore
wall ultrastructure: Review of Palaeobotany and Palynology, v. 156, p. 116-129.
Grimsson, F., and Zetter, R., 2011, Combined LM and SEM study of the Middle Miocene (Sarmatian)
palynoflora from the Lavanttal Basin, Austria: Part II. Pinophyta (Cupressaceae, Pinaceae and
Sciadopityaceae): Grana, v. 50, p. 262-310.

103
Guignard, G., Wang, Y.D., Ni, Q., Tian, N., and Jiang, Z.K., 2009, A dipteridaceous fern with in situ spores
from the Lower Jurassic in Hubei, China: Review of Palaeobotany and Palynology, v. 156, p. 104-115.
Harris, T.M., 1938, The British Rhaetic Flora: London.
—, 1964, The Yorkshire Jurassic Flora Vol. II: Caytoniales, Cycdales & Pteridosperms: London, Trustees of the
British Museum (Natural History), 191 p.
—, 1983, The Stem of Pachypteris papillosa (Thomas and Bose) Harris: Botanical Journal of the Linnean
Society, v. 86, p. 149-159.
Harris, T.M., and Museum, B., 1969, The Yorkshire Jurassic Flora Vol. III: Bennettitales, Trustees of the
British Museum (Natural History), 192 p.
He, X.Z., Shi, T.M., Wan, M.L., Wang, S.J., Hilton, J., Tang, P., and Wang, J., 2017, Peltaspermalean seed
ferns with preserved cuticle from the Upper Triassic Karamay Formation in the Junggar Basin,
northwestern China: Review of Palaeobotany and Palynology, v. 247, p. 68-82.
Hemsley, A.R., 1989, The Ultrastructure of the Spore Wall of the Triassic Bryophyte Naiadita lanceolata:
Review of Palaeobotany and Palynology, v. 61, p. 89-99.
Hermsen, E.J., Taylor, T.N., and Taylor, E.L., 2007, A voltzialean pollen cone from the Triassic of Antarctica:
Review of Palaeobotany and Palynology, v. 144, p. 113-122.
Hesse, M., Buchner, R., Svojtka, M., and Frosch-Radivo, A., 2018, Illustrated Pollen Terminology, Springer,
Cham.
Hesse, M., Halbritter, H., Weber, M., Buchner, R., Zetter, R., Ulrich, S., and Frosch-Radivo, A., 2009, Pollen
Terminology: An illustrated handbook: Austria, Springer, 266 p.
Heunisch, C., Luppold, F.W., Reinhardt, L., and Röhling, H.-G., 2010, Palynofazies, Bio- und Lithostratigrafie
im Grenzbereich Trias/Jura in der Bohrung Mariental 1 (Lappwaldmulde, Ostniedersachsen): Zeitschrift
der Deutschen Gesellschaft für Geowissenschaften, v. 161, p. 51-98.
Hieger, T.J., Serbet, R., Harper, C.J., Taylor, T.N., Taylor, E.L., and Gulbranson, E.L., 2015,
Cheirolepidiaceous diversity: An anatomically preserved pollen cone from the Lower Jurassic of
southern Victoria Land, Antarctica: Review of Palaeobotany and Palynology, v. 220, p. 78-87.
Hill, C.R., 1990, Ultrastructure of In situ Fossil Cycad Pollen from the English Jurassic, with a Description of
the Male Cone Androstrobus-Balmei sp-nov: Review of Palaeobotany and Palynology, v. 65, p. 165-
173.
Hill, R.S., 2017, History of the Australian Vegetation Cretaceous to Recent, The University of Adelaide Press,
443 p.
Hochuli, P.A., and Vigran, J.O., 2010, Climate variations in the Boreal Triassic - Inferred from palynological
records from the Barents Sea: Palaeogeography Palaeoclimatology Palaeoecology, v. 290, p. 20-42.
Hofmann, C.C., 2002, Pollen distribution in sub-recent sedimentary environments of the Orinoco Delta
(Venezuela) - an actuo-palaeobotanical study: Review of Palaeobotany and Palynology, v. 119, p. 191-
217.
Horton, D.G., 1978, Bryobrittonia-Longipes, an Earlier Name for Bryobrittonia-Pellucida (Encalyptaceae,
Musci): Brittonia, v. 30, p. 16-20.
Huang, H., Pérez-Pinedo, D., Morley, R.J., Dupont-Nivet, G., Philip, A., Win, Z., Aung, D.W., Licht, A.,
Jardine, P.E., and Hoorn, C., 2021, At a crossroads: The late Eocene flora of central Myanmar owes its
composition to plate collision and tropical climate: Review of Palaeobotany and Palynology, v. 291, p.
104441.
Huang, P., 2008, Palaeontologia Sinica:Triassic sporopollen assemblages from Santanghu Basin, Xinjiang:
Beijing, Science Press (in chinese), 240 p.
Huang, W., Dilcher, D.L., Wang, H., Na, Y.L., Li, Y.F., Li, T., and Sun, C.L., 2017, First record of Sphenarion
(Czekanowskiales) with epidermal structures from the Middle Jurassic of Inner Mongolia, China:
Palaeoworld, v. 26, p. 510-518.
Hui Ho, R., and Sziklai, O., 1973, Fine structure of the pollen surface of some taxodiaceae and cupressaceae
species: Review of Palaeobotany and Palynology, v. 15, p. 17-26.
Jiang, D., Robbins, E.I., Wang, Y., and Yang, H., 2016, Petrolipalynology, Springer, 263 p.
Joosten, H., and de Klerk, P., 2002, What's in a name? Some thoughts on pollen classification, identification,
and nomenclature in Quaternary palynology: Review of Palaeobotany and Palynology, v. 122, p. 29-45.
Kar, R.K., and Sah, S.C.D., 1969, Palynological investigation of the Gondwana outcrop from Vemavaram with
remarks on the age of the bed: Palaeobotanist, v. 18(2), p. 103-117.

104
Katagiri, T., and Hagborg, A., 2015, Validation of ordinal and family names for a Triassic fossil liverwort,
Naiadita (Naiaditaceae, Marchantiopsida): Phytotaxa, v. 222, p. 165-166.
Kelber, K.P., and van Konijnenburg-van Cittert, J.H.A., 1998, Equisetites arenaceus from the Upper Triassic of
Germany with evidence for reproductive strategies: Review of Palaeobotany and Palynology, v. 100, p.
1-26.
Kern, A.K., Harzhauser, M., Soliman, A., Piller, W.E., and Gross, M., 2012, Precipitation driven decadal scale
decline and recovery of wetlands of Lake Pannon during the Tortonian: Palaeogeography
Palaeoclimatology Palaeoecology, v. 317, p. 1-12.
Kerp, H., Abu Hamad, A., Vording, B., and Bandel, K., 2006, Typical Triassic Gondwanan floral elements in
the Upper Permian of the paleotropics: Geology, v. 34, p. 265-268.
Kerp, J.H.F., 1988, Aspects of Permian palaeobotany and palynology. X. The West- and Central European
species of the genus Autunia Krasser emend. Kerp (Peltaspermaceae) and the form-genus
Rhachiphyllum Kerp (Callipterid Foliage): Review of Palaeobotany and Palynology, v. 54, p. 249-360.
Kerp, J.H.F., Poort, R.J., Swinkels, H.A.J.M., and Verwer, R., 1990, Aspects of Permian Palaeobotany and
Palynology. IX. Conifer-dominated Rotliegend floras from the Saar-Nahe basin (? Late carboniferous-
early permian; SW-Germany) with special reference to the reproductive biology of early conifers:
Review of Palaeobotany and Palynology, v. 62, p. 205-248.
Kershaw, P., and Wagstaff, B., 2001, The southern conifer family Araucariaceae: History, status, and value for
paleoenvironmental reconstruction: Annual Review of Ecology and Systematics, v. 32, p. 397-414.
Klaus, W., 1963, Sporen aus dem südalpinen Perm, Jahrbuch Geologische Bundesanstalt Austria.
Kramer, K.U., and Green, P.S., 1990, The Families and Genera of Vascular Plants:Pteridophytes and
Gymnosperms, Springer, 404 p.
Krassilov, V., 1972, Mesozoic flora of the Bureya River. Ginkgoales and Czekanowskiales: Moscow, Akad.
Nauk SSSR Izd. Nauk (in Russian).
Krassilov, V.A., 1977, Contributions to The Knowledge of Caytoniales: Review of Palaeobotany and
Palynology, v. 24, p. 155-178.
—, 2009, Diversity of Mesozoic Gnetophytes and the First Angiosperms: Paleontological Journal, v. 43, p.
1272-1280.
Krassilov, V.A., Afonin, S.A., and Naugolnykh, S.V., 1999, Permotheca with in situ pollen grains from the
Lower Permian of the Urals: Palaeobotanist, v. 49(1), p. 19-25.
Krassilov, V.A., and Zakharov, Y.D., 1975, Pleuromeia from the lower triassic of the far east of the U.S.S.R:
Review of Palaeobotany and Palynology, v. 19, p. 221-232.
Kremp, G.O.W., and Ames, H.T., 1959, Catalog of fossil spores and pollen Volume 5: Cretaceous spores,
University Park, Pennsylvania.
—, 1961a, Catalog of fossil spores and pollen Volume 13: Carboniferous and Permian Spores, University Park,
Pennsylvania.
—, 1961b, Catalog of fossil spores and pollen Volume 14: Mesozoic and Tertiary Spores and Pollen, University
Park, Pennsylvania.
—, 1962a, Catalog of fossil spores and pollen Volume 15: Tertiary and Cretaceous Spores and Pollen,
University Park, Pennsylvania.
—, 1962b, Catalog of fossil spores and pollen Volume 16: Mesozoic and Lower Tertiary Spores and Pollen
University Park, Pennsylvania.
—, 1965a, Catalog of fossil spores and pollen Volume 23: Spores and Pollen of the Upper Cretaceous and
Cretaceous-Tertiary Boundary University Park, Pennsylvania.
—, 1965b, Catalog of fossil spores and pollen Volume 24: Mesozoic Spores and Pollen University Park,
Pennsylvania.
Kremp, G.O.W., Ames, H.T., and Grebe, H., 1957a, Catalog of fossil spores and pollen Volume 1: Cretaceous
and Tertiary Spores and Pollen, University Park, Pennsylvania, 182 p.
—, 1957b, Catalog of fossil spores and pollen Volume 2: Mesozoic and Tertiary Spores and Pollen, University
Park, Pennsylvania.
Kremp, G.O.W., Ames, H.T., and Kovar, A.J., 1958, Catalog of fossil spores and pollen Volume 4: Cretaceous
and Tertiary spores and pollen, University Park, Pennsylvania.
—, 1959, Catalog of fossil spores and pollen Volume 8: Cretaceous spores and Pollen, University Park,
Pennsylvania.

105
—, 1960a, Catalog of fossil spores and pollen Volume 9: Triassic and Jurassic spores and pollen, University
Park, Pennsylvania.
—, 1960b, Catalog of fossil spores and pollen Volume 10: Jurassic and Cretaceous Spores and Pollen,
University Park, Pennsylvania.
Kremp, G.O.W., Spackman, W., and Ames, H.T., 1966, Catalog of fossil spores and pollen Volume 25:
Mesozoic and Tertiary Spores and Pollen, University Park, Pennsylvania.
Kremp, G.O.W., Spackman, W., Traverse, A., and Ames, H.T., 1967, Catalog of fossil spores and pollen
Volume 26: Permian-Triassic Transition and Mesozoic Spores and Pollen University Park,
Pennsylvania.
—, 1968, Catalog of fossil spores and pollen Volume 28: Mesozoic Megaspores, Microspores and Pollen
University Park, Pennsylvania.
Krings, M., Klavins, S.D., DiMichele, W.A., Kerp, H., and Taylor, T.N., 2005, Epidermal anatomy of
Glenopteris splendens Sellards nov emend., an enigmatic seed plant from the Lower Permian of Kansas
(USA): Review of Palaeobotany and Palynology, v. 136, p. 159-180.
Kurmann, M.H., 1991, Pollen Ultrastructure in Elatides-Williamsonii (Taxodiaceae) from the Jurassic of North
Yorkshire: Review of Palaeobotany and Palynology, v. 69, p. 291-298.
Kustatscher, E., Hemsley, A., and Van Konijnenburg-van Cittert, J.H.A., 2009, Lugardonia paradoxa gen. et sp
nov., a new strobilus from the Anisian flora of Kuhwiesenkopf, the Dolomites, Italy and its affinities
with emphasis on spore ultrastructure: Review of Palaeobotany and Palynology, v. 156, p. 90-97.
Kustatscher, E., Kelber, K.P., and van Konijnenburg-van Cittert, J.H.A., 2012, Danaeopsis Heer ex Schimper
1869 and its European Triassic species: Review of Palaeobotany and Palynology, v. 183, p. 32-49.
Kvacek, J., Daskova, J., and Renata, P., 2006, A new schizaeaceous fern, Schizaeopsis ekrtii sp nov., and its in
situ spores from the Upper Cretaceous (Cenomanian) of the Czech Republic: Review of Palaeobotany
and Palynology, v. 140, p. 51-60.
Kvacek, J., and Pacltova, B., 2001, Bayeritheca hughesii gen. et sp nov., a new Eucommiidites-bearing pollen
organ from the Cenomanian of Bohemia: Cretaceous Research, v. 22, p. 695-704.
Labiak, P.H., Mickel, J.T., and Hanks, J.G., 2015, Molecular phylogeny and character evolution of Anemiaceae
(Schizaeales): Taxon, v. 64, p. 1141-1158.
Leslie, A.B., Herendeen, P.S., and Crane, P.R., 2009, Upatoia barnardii gen. et sp nov., an araucarian pollen
cone with in situ pollen from the Late Cretaceous (Santonian) of Georgia, USA: Grana, v. 48, p. 128-
135.
Li, L.Q., and Wang, Y.D., 2016, Late Triassic palynofloras in the Sichuan Basin, South China: Synthesis and
perspective: Palaeoworld, v. 25, p. 212-238.
Li, L.Q., Wang, Y.D., Liu, Z.S., Zhou, N., and Wang, Y., 2016, Late Triassic palaeoclimate and
palaeoecosystem variations inferred by palynological record in the northeastern Sichuan Basin, China:
Palaeontologische Zeitschrift, v. 90, p. 327-348.
Li, T., Cao, H., Kang, M., Zhang, Z., Zhao, N., and Zhang, H., 2011, Pollen Flora of China Woody Plants by
SEM, Science Press (in chinese), 1233 p.
Li, W.B., and Batten, D.J., 1986, The Early Cretaceous Megaspore Arcellites and Closely Associated
Crybelosporites Microspores from Northeast Inner-Mongolia, Pr China: Review of Palaeobotany and
Palynology, v. 46, p. 189-208.
Litwin, R.J., 1985, Fertile Organs and In situ Spores of Ferns from the Late Triassic Chinle Formation of
Arizona and New-Mexico, with Discussion of the Associated Dispersed Spores: Review of
Palaeobotany and Palynology, v. 44, p. 101-146.
Liu, Z., 2003, Palaeontologia Sinica:Triassic and Jurassic Sporopollen Assemblages from the Kuqa Depression,
Tarim Basin of Xinjiang, NW China: Beijing, Science Press (in chinese), 244 p.
Liu, Z.H., Li, C.S., and Hilton, J., 2001, Fertile pinnules of Danaeites rigida Gu and Zhi (Marattiales) from the
Upper Permian of South China: Botanical Journal of the Linnean Society, v. 136, p. 107-117.
Lugardon, B., Grauvogel-Stamm, L., and Dobruskina, I., 1999, The microspores of Pleuromeia rossica Neuburg
(Lycopsida; Triassic): comparative ultrastructure and phylogenetic implications: Comptes Rendus De L
Academie Des Sciences Serie Ii Fascicule a-Sciences De La Terre Et Des Planetes, v. 329, p. 435-442.
—, 2000, Comparative ultrastructure of the megaspores of the Triassic lycopsid Pleuromeia rossica Neuburg:
Comptes Rendus De L Academie Des Sciences Serie Ii Fascicule a-Sciences De La Terre Et Des
Planetes, v. 330, p. 501-508.

106
Lupia, R., Schneider, H., Moeser, G.M., Pryer, K.M., and Crane, P.R., 2000, Marsileaceae sporocarps and
spores from the Late Cretaceous of Georgia, USA: International Journal of Plant Sciences, v. 161, p.
975-988.
Mander, L., Collinson, M.E., Chaloner, W.G., Brain, A.P.R., and Long, D.G., 2012, The Ultrastructure and
Botanical Affinity of the Problematic Mid-Mesozoic Palynomorph Ricciisporites Tuberculatus
Lundblad: International Journal of Plant Sciences, v. 173, p. 429-440.
McKellar, J.L., 1974, Jurassic miospores from the upper Evergreen Formation, Hutton Sandstone and basal
Injune Creek Group, north-eastern Surat Basin, Geological Survey of Queensland.
McLoughlin, S., Pott, C., and Sobbe, I.H., 2018, The diversity of Australian Mesozoic bennettitopsid
reproductive organs: Palaeobiodiversity and Palaeoenvironments, v. 98, p. 71-95.
Mendes, M.M., Barron, E., Batten, D.J., and Pais, J., 2017, A new species of the spore genus
Costatoperforosporites from Early Cretaceous deposits in Portugal and its taxonomic and
palaeoenvironmental significance: Grana, v. 56, p. 401-409.
Mendes, M.M., Friis, E.M., and Pais, J., 2008, Erdtmanispermum juncalense sp nov., a new species of the
extinct order Erdtmanithecales from the Early Cretaceous (probably Berriasian) of Portugal: Review of
Palaeobotany and Palynology, v. 149, p. 50-56.
Mendes, M.M., Pais, J., Pedersen, K.R., and Friis, E.M., 2010, Erdtmanitheca portucalensis, a new pollen organ
from the Early Cretaceous (Aptian-Albian) of Portugal with Eucommiidites-type pollen: Grana, v. 49, p.
26-36.
Meyen, S.V., 1984, Basic features of gymnosperm systematics and phylogeny as evidenced by the fossil record:
The Botanical Review, v. 50, p. 1.
—, 1997, Permian conifers of Western Angaraland: Review of Palaeobotany and Palynology, v. 96, p. 351-447.
Mickel, J.T., 1982, The Genus Anemia (Schizaeaceae) in Mexico: Brittonia, v. 34, p. 388-413.
Mohr, B.A.R., Bernardes-de-Oliveira, M.E.C., Loveridge, R., Pons, D., Sucerquia, P.A., and Castro-Fernandes,
M.C., 2015, Ruffordia goeppertii (Schizaeales, Anemiaceae) - A common fern from the Lower
Cretaceous Crato Formation of northeast Brazil: Cretaceous Research, v. 54, p. 17-26.
Moisan, P., and Voigt, S., 2013, Lycopsids from the Madygen Lagerstatte (Middle to Late Triassic, Kyrgyzstan,
Central Asia): Review of Palaeobotany and Palynology, v. 192, p. 42-64.
Moller, M., Mill, R.R., Glidewell, S.M., Masson, D., Williamson, B., and Bateman, R.M., 2000, Comparative
biology of the pollination mechanisms in Acmopyle pancheri and Phyllocladus hypophyllus
(Podocarpaceae s. l.): Annals of Botany, v. 86, p. 149-158.
Morbelli, M.A., 1990, Austral South-American Jurassic Megaspores: Review of Palaeobotany and Palynology,
v. 65, p. 209-216.
Mueller, S., Krystyn, L., and Kurschner, W.M., 2016, Climate variability during the Carnian Pluvial Phase - A
quantitative palynological study of the Carnian sedimentary succession at Lunz am See, Northern
Calcareous Alps, Austria: Palaeogeography Palaeoclimatology Palaeoecology, v. 441, p. 198-211.
Muller, J., 1981, Fossil Pollen Records of Extant Angiosperms: Botanical Review, v. 47, p. 1-&.
Naugolnykh, S.V., 2009, A new fertile Neocalamites from the Upper Permian of Russia and equisetophyte
evolution: Geobios, v. 42, p. 513-523.
—, 2012, Vetlugospermum and Vetlugospermaceae: A new genus and family of peltasperms from the Lower
Triassic of Moscow syneclise (Russia): Geobios, v. 45, p. 451-462.
—, 2013a, The heterosporous lycopodiophyte Pleuromeia rossica Neuburg, 1960 from the Lower Triassic of the
Volga River basin (Russia): organography and reconstruction according to the 'Whole-Plant' concept:
Wulfenia, v. 20, p. 1-16.
—, 2013b, New male reproductive organs of gymnosperms Permotheca colovratica sp nov from the Lower
Permian of the Ural Mountains: Paleontological Journal, v. 47, p. 114-126.
—, 2014, A new genus of male cones of voltzialean affinity, Uralostrobus voltzioides nov. gen., nov. sp., from
the Lower Permian of the Urals (Russia): Geobios, v. 47, p. 315-324.
Naugolnykh, S.V., and Kerp, H., 1996, Aspects of Permian palaeobotany and palynology. XV. On the oldest
known peltasperms with radially symmetrical ovuliferous discs from the Kungurian (uppermost Lower
Permian) of the Fore-Urals (Russia): Review of Palaeobotany and Palynology, v. 91, p. 35-62.
Nemejc, F., and Pacltova, B., 1972, Hepaticae in the senonian of South Bohemia: Palaeobotanist, v. 21(1), p.
23-26.
Norris, G., 1965, Triassic and Jurassic miospores and acritarchs from the Beacon and Ferrar groups, Victoria
land, Antarctica: New Zealand Journal of Geology and Geophysics, v. 8, p. 236-277.

107
Nowak, M.D., and Lupia, R., 2005, Reinvestigation of Ariadnaesporites varius Hall and Peake, 1968 emend.
Hall, 1975: Review of Palaeobotany and Palynology, v. 135, p. 41-59.
Osborn, J.M., 1994, The morphology and ultrastructure of Caytonanthus: Canadian Journal of Botany, v. 72, p.
1519-1527.
Osborn, J.M., and Taylor, T.N., 1993, Pollen Morphology and Ultrastructure of the Corystospermales -
Permineralized in-Situ Grains from the Triassic of Antarctica: Review of Palaeobotany and Palynology,
v. 79, p. 205-219.
—, 1995, Pollen Morphology and Ultrastructure of the Bennettitales - in-Situ Pollen of Cycadeoidea: American
Journal of Botany, v. 82, p. 1074-1081.
Pacyna, G., Barbacka, M., Zdebska, D., Ziaja, J., Fijalkowska-Mader, A., Boka, K., and Sulej, T., 2017, A new
conifer from the Upper Triassic of southern Poland linking the advanced voltzialean type of ovuliferous
scale with Brachyphyllum-Pagiophyllum-like leaves: Review of Palaeobotany and Palynology, v. 245,
p. 28-54.
Pattemore, G.A., and Rozefelds, A.C., 2019, Palissya – absolutely incomprehensible or surprisingly
interpretable: a new morphological model, affiliations and phylogenetic insights: Acta Palaeobotanica, v.
59, p. 181-214.
Pedersen, K.R., Crane, P.R., and Friis, E.M., 1989, Pollen Organs and Seeds with Eucommiidites Pollen: Grana,
v. 28, p. 279-294.
Pedersen, K.R., Friis, E.M., and Crane, P.R., 1993, Pollen Organs and Seeds with Decussosporites Brenner from
Lower Cretaceous Potomac Group Sediments of Eastern USA: Grana, v. 32, p. 273-289.
Pigg, K.B., and Rothwell, G.W., 1983, Megagametophyte Development in the Chaloneriaceae Fam. Nov.,
Permineralized Paleozoic Isoetales (Lycopsida): Botanical Gazette, v. 144, p. 295-302.
Pocknall, D.T., 1981a, Pollen Morphology of the New-Zealand Species of Libocedrus Endlicher (Cupressaceae)
and Agathis Salisbury (Araucariaceae): New Zealand Journal of Botany, v. 19, p. 267-272.
—, 1981b, Pollen morphology of the New Zealand species of Dacrydium Selander, Podocarpus L'Heritier, and
Dacrycarpus Endlicher (Podocarpaceae): New Zealand Journal of Botany, v. 19, p. 67-95.
Pocock, S.A.J., Vasanthy, G., and Venkatachala, B.S., 1990, Pollen of Circumpolles - an Enigma or
Morphotrends Showing Evolutionary Adaptation: Review of Palaeobotany and Palynology, v. 65, p.
179-193.
Poort, R.J., and Kerp, J.H.F., 1990, Aspects of Permian palaeobotany and palynology. XI. On the recognition of
true peltasperms in the Upper Permian of Western and Central Europe and a reclassification of species
formerly included in Peltaspermum Harris: Review of Palaeobotany and Palynology, v. 63, p. 197-225.
Popa, M., 2019, Review of the bennettitalean genus Weltrichia: Journal of Palaeogeography-English, v. 8.
Popescu, S.M., Krijgsman, W., Suc, J.P., Clauzon, G., Marunteanu, M., and Nica, T., 2006, Pollen record and
integrated high-resolution chronology of the early Pliocene Dacic Basin (southwestern Romania):
Palaeogeography Palaeoclimatology Palaeoecology, v. 238, p. 78-90.
Potonié, R., 1956, Synopsis der Gattungen der Sporae dispersae I.Teil:Sporites, Hannover : Amt für
Bodenforschung, 103 p.
—, 1958, Synopsis der Gattungen der Sporae dispersae II.Teil:Sporites (Nachtraege), Saccites, Aletes,
Preacolpates, Polyplicates, Monocolpates: Hannover, Amt für Bodenforschung, 114 p.
—, 1960, Synopsis der Gattungen der Sporae dispersae III.Teil:Naechtrage Sporites, Forstetzung Pollenites Mit
Generalregister zu Teil I-III: Hannover, Amt für Bodenforschung, 189 p.
—, 1966, Synopsis der Gattungen der Sporae dispersae IV. Teil: Nachtraege zu allen gruppen(Turmae):
Hannover, Amt für Bodenforschung, 244 p.
—, 1967a, New phylogenetic facts on fossil spores: Review of Palaeobotany and Palynology, v. 1, p. 75-82.
—, 1967b, Versuch der Einordnung der fossilen Sporae dispersae in das phylogenetische System der
Pflanzenfamilien: Köln, Westdeutscher Verlag, 310 p.
—, 1970, Synopsis der Gattungen der Sporae dispersae V.Teil:Nachtraege zu allen gruppen(Turmae): Hannover,
Amt für Bodenforschung, 156 p.
Potonié, R., 1967, Versuch der Einordnung der fossilen Sporae dispersae in das phylogenetische System der
Pflanzenfamilien: Köln, Westdeutscher Verlag, 310 p.
Potonié, R., and Kremp, G.O.W., 1970, Synopsis der Gattungen der Sporae dispersae VI. Teil: Hannover, Amt
für Bodenforschung, 76 p.
Potonié, R., and Schweitzer, H.J., 1960, Der Pollen von Ullmannia frumentaria: Paläontologische Zeitschrift, v.
34, p. 27-39.

108
Pott, C., and McLoughlin, S., 2014, Divaricate growth habit in Williamsoniaceae (Bennettitales): unravelling
the ecology of a key Mesozoic plant group: Palaeobiodiversity and Palaeoenvironments, v. 94, p. 307-
325.
Povilauskas, L., 2012, Palynology of the Monte Chico formation (late cretaceous) from Santa Cruz Province,
Argentina: Pollen of gymnosperms: Revista Brasileira de Paleontologia v. 15, p. 85-94.
Puebla, G.G., Pramparo, M.B., and Gandolfo, M.A., 2015, Aquatic ferns from the Upper Cretaceous Loncoche
Formation, Mendoza, central-western, Argentina: Plant Systematics and Evolution, v. 301, p. 577-588.
Punt, W., Hoen, P.P., Blackmore, S., Nilsson, S., and Le Thomas, A., 2007, Glossary of pollen and spore
terminology: Review of Palaeobotany and Palynology, v. 143, p. 1-81.
Qian, C., and Chen, H., 2006, Flora of China, Volume 2, Science Press (in chinese), 406 p.
Rattanamanee, S., and Chantanaorrapint, S., 2015, Note on Notothylas yunannensis (Notothyladaceae,
Anthocerotophyta), a little known species of hornwort: Songklanakarin Journal of Science and
Technology (SJST), v. 37, p. 271-274.
Rees, P.M., 1993, Caytoniales in Early Jurassic Floras from Antarctica: Geobios, v. 26, p. 33-42.
Retallack, G., 1975, The life and times of a Triassic lycopod: Alcheringa, v. 1, p. 3-29.
Roghi, G., Gianolla, P., Minarelli, L., Pilati, C., and Preto, N., 2010, Palynological correlation of Carnian humid
pulses throughout western Tethys: Palaeogeography Palaeoclimatology Palaeoecology, v. 290, p. 89-
106.
Rossler, R., and Buschmann, B., 1994, Some Herbaceous Lycopods from the Westphalian-D of Germany:
Review of Palaeobotany and Palynology, v. 80, p. 259-275.
Rothwell, G.W., Mapes, G., Hilton, J., and Hollingworth, N.T., 2007, Pollen cone anatomy of Classostrobus
crossii sp nov (Cheirolepidiaceae): International Journal of Coal Geology, v. 69, p. 55-67.
Rothwell, G.W., and Stockey, R.A., 1994, The Role of Hydropteris pinnata gen. et. sp. nov. in Reconstructing
the Cladistics of Heterosporous Ferns: American Journal of Botany, v. 81, p. 479-492.
Rydin, C., and Friis, E.M., 2005, Pollen germination in Welwitschia mirabilis Hook. f.: differences between the
polyplicate pollen producing genera of the Gnetales: Grana, v. 44, p. 137-141.
Saxena, R.K., and Trivedi, G.K., 2009, Palynological investigation of the Kopili Formation (Late Eocene) in
North Cachar Hills, Assam, India: Acta Palaeobotanica, v. 49, p. 253-277.
Scafati, L., Melendi, D.L., and Volkheimer, W., 2009, A Danian subtropical lacustrine palynobiota from South
America (Bororo Formation, San Jorge Basin, Patagonia - Argentina): Geologica Acta, v. 7, p. 35-61.
Scheuring, B.W., 1974, On the type material of Accinctisporites Leschik, Succinctisporites Leschik,
Rimaesporites Leschik and Sahnisporites Bharadwaj: Review of Palaeobotany and Palynology, v. 17, p.
205-216.
Schimper, A.F.W., 1898, Pflanzen-geographie auf physiologischer Grundlage: Jena, Verlag von Gustav Fischer,
876 p.
Schrank, E., 2010, Pollen and spores from the Tendaguru Beds, Upper Jurassic and Lower Cretaceous of
southeast Tanzania: palynostratigraphical and paleoecological implications: Palynology, v. 34, p. 3-42.
—, 2017, Palynology of the Albian Makhtesh Qatan site, northern Negev (Israel), with descriptions of two new
pollen species: Review of Palaeobotany and Palynology, v. 246, p. 185-215.
Schuettpelz, E., Schneider, H., Smith, A.R., Hovenkamp, P., Prado, J., Rouhan, G., Salino, A., Sundue, M.,
Almeida, T.E., Parris, B., Sessa, E.B., Field, A.R., de Gasper, A.L., Rothfels, C.J., Windham, M.D.,
Lehnert, M., Dauphin, B., Ebihara, A., Lehtonen, S., Schwartsburd, P.B., Metzgar, J., Zhang, L.B., Kuo,
L.Y., Brownsey, P.J., Kato, M., Arana, M.D., Assis, F.C., Barker, M.S., Barrington, D.S., Chang, H.M.,
Chang, Y.H., Chao, Y.S., Chen, C.W., Chen, D.K., Chiou, W.L., Dittrich, V.A.D., Duan, Y.F.,
Dubuisson, J.Y., Farrar, D.R., Fawcett, S., Galan, J.M.G.Y., Goes-Neto, L.A.D., Grant, J.R., Grusz,
A.L., Haufler, C., Hauk, W., He, H., Hennequin, S., Hirai, R.Y., Huiet, L., Kessler, M., Korall, P.,
Labiak, P.H., Larsson, A., Leon, B., Li, C.X., Li, F.W., Link-Perez, M., Liu, H.M., Lu, N.T., Meza-
Torres, E.I., Miao, X.Y., Moran, R., Mynssen, C.M., Nagalingum, N., Ollgaard, B., Paul, A.M., Pereira,
J.B.D., Perrie, L.R., Ponce, M., Ranker, T.A., Schulz, C., Shinohara, W., Shmakov, A., Sigel, E.M., de
Souza, F.S., Sylvestre, L.D., Testo, W., Triana-Moreno, L.A., Tsutsumi, C., Tuomisto, H., Valdespino,
I.A., Vasco, A., Viveros, R.S., Weakley, A., Wei, R., Weststrand, S., Wolf, P.G., Yatskievych, G., Xu,
X.G., Yan, Y.H., Zhang, L., Zhang, X.C., Zhou, X.M., and Grp, P.P., 2016, A community-derived
classification for extant lycophytes and ferns: Journal of Systematics and Evolution, v. 54, p. 563-603.

109
Schwendemann, A.B., Wang, G., Mertz, M.L., McWilliams, R.T., Thatcher, S.L., and Osborn, J.A., 2007,
Aerodynamics of saccate pollen and its implications for wind pollination: American Journal of Botany,
v. 94, p. 1371-1381.
Scott, A.C., and Playford, G., 1985, Early Triassic Megaspores from the Rewan Group, Bowen Basin,
Queensland: Alcheringa, v. 9, p. 297-323.
Serbet, R., and Stockey, R.A., 1991, Taxodiaceous Pollen Cones from the Upper Cretaceous (Horseshoe
Canyon Formation) of Drumheller, Alberta, Canada: Review of Palaeobotany and Palynology, v. 70, p.
67-76.
Seyfullah, L.J., Kustatscher, E., and Taylor, W.A., 2013, The first discovery of in situ Verrucosisporites
applanatus spores from the Middle Triassic flora from Bromsgrove (Worcestershire, UK): Review of
Palaeobotany and Palynology, v. 197, p. 15-25.
Shang, Y., 2011, Palaeontologia Sinica:Late Triassic Palynology of Yunnan and Guizhou, China: Beijing,
Science Press (in chinese), 363 p.
Sheremetov, R.T., and Sheremetova, S.A., 2017, The effect of the hydrothermal conditions of the Tom River
Basin on the ecological structure of flora: Contemporary Problems of Ecology, v. 10, p. 119-130.
Shu, O.Y., and Norris, G., 1988, Spores and Pollen from the Lower Triassic Heshanggou Formation, Shaanxi
Province, North China: Review of Palaeobotany and Palynology, v. 54, p. 187-231.
—, 1999, Earliest Triassic (Induan) spores and pollen from the Junggar Basin, Xinjiang, northwestern China:
Review of Palaeobotany and Palynology, v. 106, p. 1-56.
Shuklina, A.S., and Polevova, S.V., 2007, Spores in situ and problems of the classification of Mesozoic tree
ferns: Paleontological Journal, v. 41, p. 312-318.
Smith, A.R., Pryer, K.M., Schuettpelz, E., Korall, P., Schneider, H., and Wolf, P.G., 2006, A classification for
extant ferns: Taxon, v. 55, p. 705-731.
Söderström, L., Hagborg, A., von Konrat, M., Bartholomew-Began, S., Bell, D., Briscoe, L., Brown, E., Cargill,
D.C., Costa, D.P., Crandall-Stotler, B.J., Cooper, E.D., Dauphin, G., Engel, J.J., Feldberg, K., Glenny,
D., Gradstein, S.R., He, X., Heinrichs, J., Hentschel, J., Ilkiu-Borges, A.L., Katagiri, T., Konstantinova,
N.A., Larraín, J., Long, D.G., Nebel, M., Pócs, T., Puche, F., Reiner-Drehwald, E., Renner, M.A.M.,
Sass-Gyarmati, A., Schäfer-Verwimp, A., Moragues, J.G.S., Stotler, R.E., Sukkharak, P., Thiers, B.M.,
Uribe, J., Váňa, J., Villarreal, J.C., Wigginton, M., Zhang, L., and Zhu, R.-L., 2016, World checklist of
hornworts and liverworts: PhytoKeys, p. 1-828.
Song, Z., Wang, Y., Liu, Z., Huang, B., Wang, J., Qian, L., Du, B., and Zhang, D., 1999, Fossil Spores and
Pollen of China:The Late Cretaceous and Tertiary Spores and Pollen: Beijing, Science Press (in
chinese), 910 p.
—, 2000, Fossil Spores and Pollen of China: The Mesozoic Spores and Pollen: Beijing, Science Press (in
chinese), 710 p.
Song, Z.C., Wang, W.M., and Huang, F., 2004, Fossil pollen records of extant angiosperms in China: Botanical
Review, v. 70, p. 425-458.
Specht, R.L., Dettmann, M.E., and Jarzen, D.M., 1992, Community Associations and Structure in the Late
Cretaceous Vegetation of Southeast Australasia and Antarctica: Palaeogeography Palaeoclimatology
Palaeoecology, v. 94, p. 283-309.
Srivastava, S.K., 1971, Systematic Revision of Genus Styx Norton Et Hall, 1967: Review of Palaeobotany and
Palynology, v. 11, p. 297-+.
—, 1987, Jurassic Spore-Pollen Assemblages from Normandy (France) and Germany: Geobios, v. 20, p. 5-79.
—, 1994, Evolution of Cretaceous Phytogeoprovinces, Continents and Climates: Review of Palaeobotany and
Palynology, v. 82, p. 197-224.
Steart, D.C., Spencer, A.R.T., Garwood, R.J., Hilton, J., Munt, M.C., Needham, J., and Kenrick, P., 2014, X-ray
Synchrotron Microtomography of a silicified Jurassic Cheirolepidiaceae (Conifer) cone: histology and
morphology of Pararaucaria collinsonae sp nov.: Peerj, v. 2, p. 1-29.
Suc, J.P., and Fauquette, S., 2012, The use of pollen floras as a tool to estimate palaeoaltitude of mountains: The
eastern Pyrenees in the Late Neogene, a case study: Palaeogeography Palaeoclimatology Palaeoecology,
v. 321, p. 41-54.
Sun, K., Cui, J., and Wang, S., 2010, Fossil Flora of China (vol 2): Fossil Pteridophytyes in China, Higher
Education Press (in chinese), 438 p.
Taylor, E.L., and Taylor, T.N., 2006, Mesozoic seed ferns: Old paradigms, new discoveries: Journal of the
Torrey Botanical Society, v. 133, p. 62-82.

110
—, 2009, Seed Ferns from the Late Paleozoic and Mesozoic: Any Angiosperm Ancestors Lurking There?:
American Journal of Botany, v. 96, p. 237-251.
Taylor, E.L., Taylor, T.N., Kerp, H., and Hermsen, E.I., 2006, Mesozoic seed ferns: Old paradigms, new
discoveries: Journal of the Torrey Botanical Society, v. 133, p. 62-82.
Taylor, E.L., Taylor, T.N., and Krings, M., 2009, Paleobotany:The Biology and Evolution of Fossil Plants:
London, Academic Press, 1252 p.
Taylor, T.N., 1973, A consideration of the morphology, ultrastructure and multicellular microgametophyte of
Cycadeoidea dacotensis pollen: Review of Palaeobotany and Palynology, v. 16, p. 157-164.
Taylor, T.N., Cichan, M.A., and Baldoni, A.M., 1984, The Ultrastructure of Mesozoic Pollen - Pteruchus dubius
(Thomas) Townrow: Review of Palaeobotany and Palynology, v. 41, p. 319-327.
Taylor, T.N., and Grauvogel-Stamm, L., 1995, The Ultrastructure of Voltzialean Pollen: Review of
Palaeobotany and Palynology, v. 84, p. 281-303.
Tekleva, M., 2016, Pollen morphology and ultrastructure of several Gnetum species: an electron microscopic
study: Plant Systematics and Evolution, v. 302, p. 291-303.
Tekleva, M.V., and Krassilov, V.A., 2009, Comparative pollen morphology and ultrastructure of modern and
fossil gnetophytes: Review of Palaeobotany and Palynology, v. 156, p. 130-138.
Tekleva, M.V., Polevova, S.V., and Zavialova, N.E., 2007, On some peculiarities of sporoderm structure in
members of the Cycadales and Ginkgoales: Paleontological Journal, v. 41, p. 1162-1178.
Tekleva, M.V., and Roghi, G., 2018, Lagenella martini from the Triassic of Austria – Exine structure and
relationships with other striate palynomorphs: Review of Palaeobotany and Palynology, v. 258, p. 13-21.
Thomas, H.H., and Seward, A.C., 1925, VI. The caytoniales, a new group of angiospermous plants from the
Jurassic Rocks of Yorkshire: Philosophical Transactions of the Royal Society of London. Series B,
Containing Papers of a Biological Character, v. 213, p. 299-363.
Townrow, J.A., 1962, On Some Disaccate Pollen Grains of Permian to Middle Jurassic Age: Grana, v. 3, p. 13-
44.
Traverse, A., 2007, Paleopalynology Second Edition: The Netherlands, Springer, 813 p.
Traverse, A., and Ames, H.T., 1968, Catalog of fossil spores and pollen Volume 29: Mesozoic and Cenozoic
Spores, Pollen and Other Microfossils University Park, Pennsylvania.
—, 1969, Catalog of fossil spores and pollen Volume 30: Mesozoic and Cenozoic Spores and Pollen University
Park, Pennsylvania.
—, 1971, Catalog of fossil spores and pollen Volume 33: Cretaceous Pollen and Spores University Park,
Pennsylvania.
—, 1972, Catalog of fossil spores and pollen Volume 35: Permian Pollen and Spores, University Park,
Pennsylvania.
—, 1979, Catalog of fossil spores and pollen Volume 41: Late Cretaceous and Early Tertiary Spores and Pollen
from the U.S.A. and the U.S.S.R., University Park, Pennsylvania.
Traverse, A., Ames, H.T., and Spackman, W., 1973a, Catalog of fossil spores and pollen Volume 36:
Cretaceous Pollen and Spores University Park, Pennsylvania.
—, 1973b, Catalog of fossil spores and pollen Volume 37: Paleozoic Megaspores and Miospores, University
Park, Pennsylvania.
—, 1974, Catalog of fossil spores and pollen Volume 38: Mesozoic Pollen and Spores, University Park,
Pennsylvania.
—, 1975, Catalog of fossil spores and pollen Volume 39: Mesozoic Pollen and Spores, University Park,
Pennsylvania.
Traverse, A., Spackman, W., and Ames, H.T., 1969, Catalog of fossil spores and pollen Volume 31: Mesozoic
and Cenozoic Spores and Pollen University Park, Pennsylvania.
Tryon, A.F., and Lugardon, B., 1991, Spores of the Pteridophyta, Springer, 648 p.
Uhl, D., Abu Hamad, A., Kerp, H., and Bandel, K., 2007, Evidence for palaeo-wildfire in the Late Permian
palaeotropics - charcoalified wood from the Um Irna Formation of Jordan: Review of Palaeobotany and
Palynology, v. 144, p. 221-230.
Vakhrameev, V.A., 1987, Climates and the distribution of some gymsosperms in Asia during the Jurassic and
Cretaceous: Review of Palaeobotany and Palynology, v. 51, p. 205-212.
—, 1991, Jurassic and Cretaceous Floras and Climates of the Earth: Cambridge, Cambridge University Press,
318 p.

111
Van der Eem, J.G.L.A., 1983, Aspects of Middle and Late Triassic Palynology .6. Palynological Investigations
in the Ladinian and Lower Karnian of the Western Dolomites, Italy: Review of Palaeobotany and
Palynology, v. 39, p. 189-300.
van Konijnenburg-van Cittert, J.H.A., 1971, In Situ Gymnosperm Pollen from Middle Jurassic of Yorkshire:
Acta Botanica Neerlandica, v. 20, p. 1-&.
—, 1978, Osmundaceous Spores In situ from Jurassic of Yorkshire, England: Review of Palaeobotany and
Palynology, v. 26, p. 125-141.
—, 1981, Schizaeaceous Spores In situ from the Jurassic of Yorkshire, England: Review of Palaeobotany and
Palynology, v. 33, p. 169-181.
—, 1989, Dicksoniaceous Spores In situ from the Jurassic of Yorkshire, England: Review of Palaeobotany and
Palynology, v. 61, p. 273-301.
—, 1992, An Enigmatic Liassic Microsporophyll, Yielding Ephedripites Pollen: Review of Palaeobotany and
Palynology, v. 71, p. 239-254.
—, 2002, Ecology of some Late Triassic to Early Cretaceous ferns in Eurasia: Review of Palaeobotany and
Palynology, v. 119, p. 113-124.
van Konijnenburg-van Cittert, J.H.A., Kustatscher, E., Pott, C., Dutsch, G., and Schmeissner, S., 2017, First
record of the pollen-bearing reproductive organ Hydropterangium from the Rhaetian of Germany
(Wustenwelsberg, Upper Franconia): Neues Jahrbuch Fur Geologie Und Palaontologie-Abhandlungen,
v. 284, p. 139-151.
Van Konijnenburg-van Cittert, J.H.A., Pott, C., Schmeißner, S., Dütsch, G., and Kustatscher, E., 2021, The
Rhaetian flora of Wüstenwelsberg, Bavaria, Germany: Description of selected gymnosperms
(Ginkgoales, Cycadales, Coniferales) together with an ecological assessment of the locally prevailing
vegetation: Review of Palaeobotany and Palynology, v. 288, p. 104398.
Veisberg, E.I., 2017, Species structure of plant groupings in the shallow coastal zone of piedmont lake Bolshoe
Miassovo (Southern Urals): Inland Water Biology, v. 10, p. 275-285.
Verma, P.K., Rawat, K.K., and Kumar, R., 2014, Anthoceros subtilis Steph: A Rare Disjunct Species, New to
North East India from Brahmaputra Valley: Proceedings of the National Academy of Sciences, India
Section B: Biological Sciences, v. 84, p. 811-813.
Villarreal, J.C., Cargill, C., Söderström, L., Hagborg, A., and Konrat, M.v., 2015, Notes on Early Land Plants
Today. 70. Nomenclatural notes in hornworts (Anthocerotophyta): Phytotaxa, v. 208, p. 92-96.
Visscher, H., and van der Zwan, C.J., 1981, Palynology of the circum-mediterranean triassic: Phytogeographical
and palaeoclimatological implications: Geologische Rundschau, v. 70, p. 625-634.
Vitt, D.H., and Hamilton, C.D., 1974, A scanning electron microscope study of the spores and selected
peristomes of the North American Encalyptaceae (Musci): Canadian Journal of Botany, v. 52, p. 1973-
1981.
Volkheimer, W., and Scafati, L., 2007, Palynology of a Danian warm climatic wetland in Central Northern
Patagonia, Argentina: Revista española de micropaleontología, v. 39, p. 117-134.
Wan, M.L., Zhou, W.M., He, X.Z., Liu, L.J., and Wang, J., 2016, A typical Euramerican floral element from the
Shanxi Formation (Cisuralian, lower Permian) in the Wuda Coal Field, Inner Mongolia, North China:
Palaeobiodiversity and Palaeoenvironments, v. 96, p. 507-515.
Wan, Z.H., and Basinger, J.F., 1992, On the Fern Pectinangium Li Et-Al, Emend (Marattiales), with Spores
Insitu from the Permian of Southern China: Review of Palaeobotany and Palynology, v. 75, p. 219-238.
Wang, C.S., Feng, Z.G., Zhang, L.M., Huang, Y.J., Cao, K., Wang, P.J., and Zhao, B., 2013, Cretaceous
paleogeography and paleoclimate and the setting of SKI borehole sites in Songliao Basin, northeast
China: Palaeogeography Palaeoclimatology Palaeoecology, v. 385, p. 17-30.
Wang, Q., and Dai, X., 2010, Spores of Polypodiales (Filicales) from China, Science Press (in chinese), 262 p.
Wang, Y.-D., Ni, Q., Jiang, Z.-K., and Tian, N., 2008, Diversity variation and tempo-spatial distribution of
Otozamites (Bennettitales) in the Mesozoic of China: Palaeoworld, v. 17, p. 222-234.
Wang, Y.D., 1999a, Fertile organs and in situ spores of Marattia asiatica (Kawasaki) Harris (Marattiales) from
the Lower Jurassic Hsiangchi Formation in Hubei, China: Review of Palaeobotany and Palynology, v.
107, p. 125-144.
Wang, Y.D., Mosbrugger, V., and Zhang, H., 2005, Early to Middle Jurassic vegetation and climatic events in
the Qaidam Basin, northwest China: Palaeogeography Palaeoclimatology Palaeoecology, v. 224, p. 200-
216.

112
Wang, Y.D., Yang, X.J., Guignard, G., Deng, S.H., Tian, N., and Jiang, Z.K., 2009, The fossil Gleicheniaceous
ferns of China: Biodiversity, systematics, spore ultrastructure and evolution: Review of Palaeobotany
and Palynology, v. 156, p. 139-156.
Wang, Z., 2012, A bizarre Palissya ovulate organ from Upper Triassic strata of the Zixing coal field, Hunan
Province, China: Science Bulletin, v. 57, p. 1169-1177.
Wang, Z.Q., 1999b, Gigantonoclea: An enigmatic Permian plant from North China: Palaeontology, v. 42, p.
329-373.
Wang, Z.Q., and Wang, L.X., 1982, A New Species of the Lycopsid Pleuromeia from the Early Triassic of
Shanxi, China, and Its Ecology: Palaeontology, v. 25, p. 215-225.
Wang, Z.X., Sun, F.K., Jin, P.H., Chen, Y.Q., Chen, J.W., Deng, P., Yang, G.L., and Sun, B.N.A., 2017, A New
Species of Ginkgo with Male Cones and Pollen Grains in situ from the Middle Jurassic of Eastern
Xinjiang, China: Acta Geologica Sinica-English Edition, v. 91, p. 9-21.
Warming, E., 1895, Plantesamfund - Grundtræk af den økologiske Plantegeografi, Clarendon Press, Oxford,
335 p.
Warny, S., Jarzen, D.M., Evans, A., Hesp, P., and Bart, P., 2012, Environmental significance of abundant and
diverse hornwort spores in a potential submerged Paleoindian site in the Gulf of Mexico: Palynology, v.
36, p. 234-253.
Wetschnig, W., and Depisch, B., 1999, Pollination biology of Welwitschia mirabilis HOOK. f.
(Welwitschiaceae, Gnetopsida): Phyton-Annales Rei Botanicae, v. 39, p. 167-183.
White, J.M., Jessop, C.M., Scotese, C.R., Lai, G., and da Roza, R.J., 2009, Depicting Biostratigraphical Data
from Palynodata: Experiments and Questions in Data Presentation and Manipulation: Palynology, v. 33,
p. 157-174.
Wilde, V., and Hemsley, A.R., 2000, Morphology, ultrastructure and affinity of barremian (lower cretaceous)
megaspores dijkstraisporites and paxillitriletes from Brilonnehden, Germany: Palynology, v. 24, p. 217-
230.
Worobiec, E., 2009, Middle Miocene palynoflora of the Legnica lignite deposit complex, Lower Silesia, Poland:
Acta Palaeobotanica, v. 49, p. 5-133.
Yang, G.X., Sheng, A.X., and Wang, H.S., 1997, A new species: Szea (Cladophlebis) henanense sp nov in
Henan Province and its evolutional significance: Chinese Science Bulletin, v. 42, p. 1023-1028.
Yang, X.J., 2008, A male cone of Pseudofrenelopsis dalatzensis with in situ pollen grains from the Lower
Cretaceous of Northeast China: Geobios, v. 41, p. 689-698.
Yang, Z.P., Gao, J.X., Zhao, L., Xu, X.L., and Ouyang, H., 2013, Linking thaw depth with soil moisture and
plant community composition: effects of permafrost degradation on alpine ecosystems on the Qinghai-
Tibet Plateau: Plant and Soil, v. 367, p. 687-700.
Yao, Z.Q., and Taylor, T.N., 1988, On a New Gleicheniaceous Fern from the Permian of South China: Review
of Palaeobotany and Palynology, v. 54, p. 121-134.
Yurtsev, B.A., 2001, The Pleistocene "Tundra-Steppe" and the productivity paradox: the landscape approach:
Quaternary Science Reviews, v. 20, p. 165-174.
Zavada, M.S., 1990, The ultrastructure of three monosulcate pollen grains from the triassic chinle formation,
western United States Palynology, v. 14, p. 41-51.
Zavada, M.S., and Crepet, W.L., 1986, Pollen Grain Wall Structure of Caytonanthus-Arberi (Caytoniales): Plant
Systematics and Evolution, v. 153, p. 259-264.
Zavialova, N., Buratti, N., and Roghi, G., 2010, The ultrastructure of some Rhaetian Circumpolles from
southern England: Grana, v. 49, p. 281-299.
Zavialova, N., Gordenko, N., Nosova, N., and Polevova, S., 2014, The fine morphology of pollen grains from
the pollen chamber of a supposed ginkgoalean seed from the Middle Jurassic of Uzbekistan (Angren
locality): Plant Systematics and Evolution, v. 300, p. 1995-2008.
Zavialova, N., and Karasev, E., 2015, Exine ultrastructure of in situ Protohaploxypinus from a Permian
peltasperm pollen organ, Russian Platform: Review of Palaeobotany and Palynology, v. 213, p. 27-41.
Zavialova, N., Markevich, V., Bugdaeva, E., and Polevova, S., 2011, The ultrastructure of fossil dispersed
monosulcate pollen from the Early Cretaceous of Transbaikalia, Russia: Grana, v. 50, p. 182-201.
Zavialova, N., and van Konijnenburg-van Cittert, J.H.A., 2011, Exine ultrastructure of in situ peltasperm pollen
from the Rhaetian of Germany and its implications: Review of Palaeobotany and Palynology, v. 168, p.
7-20.

113
—, 2012, Exine ultrastructure of in situ pollen from the cycadalean cone Androstrobus prisma Thomas et Harris
1960 from the Jurassic of England: Review of Palaeobotany and Palynology, v. 173, p. 15-22.
—, 2016, Exine ultrastructure of in situ pollen from the cycadalean cone Androstrobus manis Harris, 1941 from
the Jurassic of England: Review of Palaeobotany and Palynology, v. 225, p. 33-42.
Zavialova, N.E., and Gomankov, A.V., 2009, Occurrence of angiosperm-like ultrastructural features in
gymnosperm pollen from the Permian of Russia: Review of Palaeobotany and Palynology, v. 156, p.
79-89.
Zavialova, N.E., and Roghi, G., 2005, Exine morphology and ultrastructure of Duplicisporites from the Triassic
of Italy: Grana, v. 44, p. 337-342.
Zavialova, N.E., Tekleva, M.V., Polevova, S.V., and Bogdanov, A.G., 2018, Electron microscopy for
morphology of pollen and spores: Moscow:, RIPOL Classic Press, 334 p.
Zeng, J., and Huo, C., 2004, Flora of China, Volume 6(3), Science Press (in chinese), 313 p.
Zetter, R., Farabee, M.J., Pigg, K.B., Manchester, S.R., DeVore, M.L., and Nowak, M.D., 2011, Palynoflora of
the late Paleocene silicified shale at Almont, North Dakota, USA: Palynology, v. 35, p. 179-211.
Zhang, J., Lenz, O.K., Hornung, J., Wang, P., Ebert, M., and Hinderer, M., 2020, Palynology and the Eco-Plant
model of peat-forming wetlands of the Upper Triassic Haojiagou Formation in the Junggar Basin,
Xinjiang, NW China: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 556, p. 109888.
Zhang, J., Lenz, O.K., Wang, P., Gao, Y., and Hornung, J., 2021a, Database-based Eco-Plant analysis for
Mesozoic dispersed sporomorphs: MethodsX, v. 8, p. 101329.
Zhang, J., Lenz, O.K., Wang, P., and Hornung, J., 2021b, The Eco-Plant model and its implication on Mesozoic
dispersed sporomorphs for Bryophytes, Pteridophytes, and Gymnosperms: Review of Palaeobotany and
Palynology, v. 293, p. 104503.
Zhang, Y., Wu, P., Wang, C., Jia, Y., Luo, J., and Lin, B., 2006, Spore Morphology of Chinese Bryophytes:
Qingdao, Qindao Press (in chinese), 339 p.
Zhao, J., Wan, X.Q., Xi, D.P., Jing, X., Li, W., Huang, Q.H., and Zhang, J.Y., 2014, Late Cretaceous
palynology and paleoclimate change: Evidence from the SK1 (South) core, Songliao Basin, NE China:
Science China-Earth Sciences, v. 57, p. 2985-2997.
Zhao, Y., Lu, Y.Z., Shang, P., Deng, S.H., and Wang, X.L., 2018, An amended species, Nilssoniopteris
neimenguensis nom. nov., from the Lower Jurassic of the Xilinhot Basin, Inner Mongolia, northern
China, with a reexamination of Nilssoniopteris species: Review of Palaeobotany and Palynology, v. 255,
p. 22-34.
Zhou, Z.-Y., 2009, An overview of fossil Ginkgoales: Palaeoworld, v. 18, p. 1-22.

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