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Lemma micromorphology and the systematics of Siberian species of Stipa (Poaceae)
Nordic Journal of Botany
Abstract
We investigated the lemma micromorphology of 17, primarily Siberian, species of Stipa using scanning electron microscopy (SEM). All the species had variants of the micromorphology considered typical for Stipa but each had a unique combination of characteristics, enabling its identification solely on the basis of its lemma micromorphology. Phenetic analysis revealed little correlation between the observed variation and the current sectional treatment of the species. The data support exclusion of Stipa borysthenica from Stipa pennata. A key to the species is provided.
... (1999),Acedo & Llamas (2001),Liu et al. (2010),Mashau et al. (2015) andOlonova et al. (2016) (Appendix 3). SEMs were captured near the mid-point of mature first lemmas (bearing a caryopsis). ...
Thompson, E.J. (2023). Two new species of Enteropogon Nees (Poaceae: Chloridoideae: Cynodonteae: Eleusininae) for northern Australia. Austrobaileya 13: 51−93. Two new species, Enteropogon pubifolius E.J.Thomps. and E. scabrilemma E.J.Thomps., with morphological similarities to E. paucispiceus (Lazarides) B.K.Simon and E. macrostachyus (Hochst. ex A.Rich.) Munro ex Benth., respectively, are described and illustrated. Enteropogon pubifolius differs from other Australian species by a combination of characteristics including the pubescent, broader basal leaves, and E. scabrilemma by the scabrid broader lemmas and inflorescences with usually one or two rigid racemes. Some morphological characters used to identify Australian species of Enteropogon were found to be variable and consequently, a new modified key was developed to reduce potential ambiguity. Results from phenetic analyses of 43 morphological characters were used to explore hypotheses for the taxonomic relationships of the species.
... Observations of micromorphology were made from SEMs of lower lemmas, upper lemmas and upper paleas. Silica bodies, stomata, epidermal long cell walls, microhairs and macrohairs were classified using the terminology of previous authors (Hsu 1965;Jirasek & Jozifova 1968;Ellis 1979;Valdes-Reyna & Hatch 1991;Snow 1996;Acedo & Llamas 2001;Liu et al. 2010;Mashau et al. 2015;Olonova et al. 2016;Neumann et al. 2017). ...
... Silica bodies, stomata, epidermal long cell walls, microhairs and macrohairs on lower lemmas and upper lemmas and paleas were classified following other authors (Hsu 1965;Jirasek and Jozifova 1968;Ellis 1979;Valdes-Reyna and Hatch 1991;Snow 1996;Acedo and Llamas 2001;Liu et al. 2010;Mashau et al. 2015;Olonova et al. 2016;Neumann et al. 2017). Lodicules on fresh material were classified as plicate or non-plicate (Hsu 1965;Jirasek and Jozifova 1968;Guedes and Dupuy 1976). ...
A new genus, Simonachne E.J.Thomps. is described and Ancistrachne maidenii (A.A.Ham.) Vickery is transferred to it as Simonachne maidenii (A.A.Ham.) E.J.Thomps. The new subtribe Cleistochloinae E.J.Thomps. is described and is composed of four genera, Calyptochloa, Cleistochloa, Dimorphochloa and Simonachne, united by distinctive morphology that is associated with reproductive dimorphism. Phenetic analyses were used to examine the similarities of taxa and to test the consistency of results with variation in analysis inputs. Input variations included the dataset in terms of composition of the samples and morphological characters, and the cluster analysis algorithms, viz. classification, ordination and association measure. A baseline dataset was used for comparison of results and comprised 24 samples and 161 characters relating to anatomy, micro- and macromorphology of spikelets, leaves and fertile culms. Three major clusters were resolved, Cleistochloinae (‘the cleistogamy group’), Neurachninae in its original sense, and a cluster referred to as the ‘paniculate inflorescence group’ composed of Ancistrachne s.s., Entolasia and Panicum s.s. The results were congruent with a recent phylogenetic study that showed that Ancistrachne s.l., Cleistochloa s.l. and Dimorphochloa s.l. were not monophyletic. The process provided an array of morphological characters for descriptions of species and for distinguishing taxa at multiple ranks in natural groups, components of alpha and beta taxonomy respectively.
... More recently, Romaschenko et al. (2010Romaschenko et al. ( , 2012 have described two major lemma epidermal patterns in the tribe: Stipa-like, also called saw-like, dominated by long fundamental cells and hooks, and Achnatherum-like, also called maize-like, dominated by short fundamental cells and paired with silica cells. Several authors have shown out that, even though LEP is relatively uniform within a genus, it may still be useful in identifying particular species as well as in delineating relationships among and between different subgenera or sections (Ortúñez and de la Fuente, 2010;Nobis, 2013;Olonova et al., 2016;Nobis et al., 2019b), but lemmas of relatively few Austrostipa species had been studied prior to Bustam's (2010;2012) work. ...
The mainly Australian grass genus Austrostipa (tribe Stipeae) comprising approximately 64 species represents a remarkable example of an evolutionary radiation. To investigate aspects of diversification, macro- and micromorphological variation in this genus, we conducted molecular phylogenetic and scanning electron microscopy (SEM) analyses including representatives from most of Austrostipa’s currently accepted subgenera. Because of its taxonomic significance in Stipeae, we studied the lemma epidermal pattern (LEP) in 34 representatives of Austrostipa. Plastid DNA variation within Austrostipa was low and only few lineages were resolved. Nuclear ITS and Acc1 yielded comparable groupings of taxa and resolved subgenera Arbuscula, Petaurista, and Bambusina in a common clade and as monophyletic. In most of the Austrostipa species studied, the LEP was relatively uniform (typical maize-like), but six species had a modified cellular structure. The species representing subgenera Lobatae, Petaurista, Bambusina as well as A. muelleri from subg. Tuberculatae were well-separated from all the other species included in the analysis. We suggest recognizing nine subgenera in Austrostipa (with number of species): Arbuscula (4), Aulax (2), Austrostipa (36), Bambusina (2), Falcatae (10), Lobatae (5), Longiaristatae (2), Petaurista (2) and the new subgenus Paucispiculatae (1) encompassing A. muelleri. Two paralogous sequence copies of Acc1, forming two distinct clades, were found in polyploid Austrostipa and Anemanthele. We found analogous patterns for our samples of Stipa s.str. with their Acc1 clades strongly separated from those of Austrostipa and Anemanthele. This underlines a previous hypothesis of Tzvelev (1977) that most extant Stipeae are of hybrid origin. We also prepared an up-to-date survey and reviewed the chromosome number variation for our molecularly studied taxa and the whole tribe Stipeae. The chromosome base number patterns as well as dysploidy and whole-genome duplication events were interpreted in a phylogenetic framework. The rather coherent picture of chromosome number variation underlines the enormous phylogenetic and evolutionary significance of this frequently ignored character.
... Micromorphology. The micromorphological examination of Stipa bungeana, S. krylovii and their putative hybrid revealed the pattern of lemma that is typical for the genus Stipa (Fig. 3) 45,60,62,70,71 . In all three taxa, the fundamental long cells are rectangular to more or less square in shape. ...
Hybridisation in the wild between closely related species is a common mechanism of speciation in the plant kingdom and, in particular, in the grass family. Here we explore the potential for natural hybridisation in Stipa (one of the largest genera in Poaceae) between genetically distant species at their distribution edges in Mountains of Central Asia using integrative taxonomy. Our research highlights the applicability of classical morphological and genome reduction approaches in studies on wild plant species. The obtained results revealed a new nothospecies, Stipa × lazkovii, which exhibits intermediate characters to S. krylovii and S. bungeana. A high-density DArTseq assay disclosed that S. × lazkovii is an F1 hybrid, and established that the plastid and mitochondrial DNA was inherited from S. bungeana. In addition, molecular markers detected a hybridisation event between morphologically and genetically distant species S. bungeana and probably S. glareosa. Moreover, our findings demonstrated an uncertainty on the taxonomic status of S. bungeana that currently belongs to the section Leiostipa, but it is genetically closer to S. breviflora from the section Barbatae. Finally, we noticed a discrepancy between the current molecular data with the previous findings on S. capillata and S. sareptana.
... Epidermal features characterize major stipoid groups based on the length and shape of fundamental cells, silica cells, cork cells, and prickles, among others, resulting in different epidermal patterns (Romaschenko et al. 2008(Romaschenko et al. , 2012Nobis 2013;Olonova et al. 2016). The Maize-like pattern is restricted to the American clade and Pappostipa (Romaschenko et al. 2008(Romaschenko et al. , 2012. ...
Within grasses, the tribe Stipeae is highly specialized by the presence of only one fruit per spikelet and characterized by the diversity in the ornamentation of the floret. Our aim was to analyze similarities and differences based on multi-and univariate analyses among closely related species in American Stipeae: Jarava species with plumose-like awns and species of Pappostipa with pappus-like awns. Ordination analyses (principal coordinate analysis and cluster analysis) were used to determine major groupings, while significant differences among groups were tested by multivariate analysis of variance (MANOVA) and univariate analysis based on generalized linear models (GLM). Based on morphological similarities, we delimited five groups. The presence of a small floret characterized Jarava annua, J. media, and J. plumosula, although J. annua was clearly distinguished by the distribution of hairs in the awn column. Jarava subplumosa and J. psylantha were characterized by the pubescence of the culm, the length of the floret callus, the length of the awn subule, and the length of the awn hairs. Pappostipa was distinctive by having hairs only in the awn column that resemble a pappus while Jarava neaei 1 J. pogonathera presented the longest inflorescences and hairs only on the awn subule, resembling a feather. As a result, we present a key to taxa and descriptions to characterize and identify species within the Jarava-Pappostipa group with plumose and pappus-like awns.
... In total, from 400 to 600 species were included in the genus Stipa; according to the modern concepts, they belong to 28 genera united into the tribe Stipeae [6][7][8]. Currently, approximately 150 species have been assigned to the genus Stipa [9]. Some species are dominants and edificators of steppe communities and occupy vast areas, while others are very rare and need protection. ...
The ITS1–5.8S rDNA–ITS2 sequence of the 35S rRNA genes of 16 species of feather grasses and 2 species of false needlegrasses of the flora of the Altai Republic and Altai krai (Stipa baicalensis, S. borysthenica, S. capillata, S. consanguinea, S. dasyphylla, S. desertorum, S. glareosa, S. grandis, S. korshinskyi, S. krylovii, S. lessingiana, S. orientalis, S. pennata, S. praecapillata, S. pulcherrima, S. zalesskii, Ptilagrostis junatovii, and P. mongholica), as well as four feather grass species from other regions of Russia (S. pontica, S. rubens, S. tirsa, and S. ucrainica), was sequenced. The trnL-trnF chloroplast sequences of S. capillata, S. borysthenica, S. glareosa, S. krylovii, S. lessingiana, S. orientalis, S. pulcherrima, and S. zalesskii were also determined. The trnL-trnF region, as well as the 5.8S rDNA, is highly conserved in feather grasses and cannot be used to differentiate sections and species within the genus. The ITS1 and ITS2 sequences, on the contrary, have some parsimony-informative substitutions and indels, which makes it possible to identify groups of ribotypes corresponding to sections and individual species within some sections. The clades corresponding to the Stipa and
Leiostipa sections were separated; the species of the Barbatae and Subbarbatae sections composed the same clade, while the section Hemibarbatae turned out to be polyphyletic. Only in the section Stipa were no species-specific nucleotide substitutions and indels revealed. The isolation of the species S. desertorum, the taxonomic rank of which was previously unclear, was shown. The origin of polymorphic sites in the ITS sequences of feather grasses is discussed as possible evidence of distant hybridization.
... Patterns of lemma micromorphology in Stipa heptapotamica, S. lessingiana, and S. richteriana s.l., are rather similar, and at the same time typical of the genus Stipa (Nobis, 2013;Olonova et al., 2016). In all three taxa, fundamental cells, which are dominant structures on the lemma surface, range from rectangular to more or less square in shape. ...
Hybridisation, considered one of the major drivers of speciation in plants, commonly occurs among many genera of grasses, including the genus Stipa L. one of the largest in the family Poaceae in the Old World. In the course of research on Stipa, we studied S. richteriana, S. lessingiana, and their putative hybrid S. heptapotamica, all of which grow in south-eastern Kazakhstan. Stipa heptapotamica is treated as a local endemic, known only from the eastern part of the country. We used an integrative approach, combining morphological and molecular data, to validate the status of the hybrid taxon and present for the first time clear data documenting natural hybridisation in Stipa. The macro- and micromorphological analyses presented here show S. heptapotamica to be intermediate to its parental species in the characters studied; pollen analysis demonstrates low viability of pollen grains (below 50% compared to 94% and 87% in S. lessingiana and S. richteriana, respectively); molecular analyses based on inter simple sequence repeat markers (ISSR) and next-generation sequencing (NGS) data prove that S. heptapotamica originated strictly from hybridisation events involving S. richteriana and S. lessingiana. ISSR markers reveal possible introgression events between S. lessingiana and S. heptapotamica, whereas NGS data analyses confirm the maternal inheritance of a plastome from S. lessingiana in S. heptapotamica and support the finding of cryptic lineages within S. richteriana.
... менчивости были проведены многомерные анализы -факторный и анализ главных компонент, Статистическая обработка данных проводилась при помощи языка программирования R 3.4.2 в среде RStudio. Характер поверхности нижней цветковой чешуи является важным систематическим признаком (Vignal, 1984;Peterson, 1989;Bell, Columbus, 2008;Gudkova and Olonova, 2012;Olonova et. al., 2016;Nobis et. al., 2016 и др.). Ее ультраструктура была исследована на сканирующем электронном микроскопе SNE-4500M (Корея). Для этого исследования нижние цветковые чешуи фиксировали на двустороннем электропроводящем углеродном скотче. Для уменьшения влияния заряда их обрабатывали методом термического напыления в вакууме золотом. Образцы исс ...
The genus Stipa in the Altai territory is represented by 12 species (Lomonosova, 2003, Silanteva, 2013, Gudkova et al., 2015). Stipacapillata L., which belongs to the Leiostipa Dumor. section, is one of the most widespread species of this genus. Besides S. capillata, two more species of this section – S. praecapillata Alech. and S. Baicalensis Roshev. occur on the territory of the region. However, they both have a very limited distribution: the first is represented by single finds in Klyuchevsky, Kuryinsky, Pospelikhinsky and Rubtsovsky districts of Altay, and the latter one occurs only in Charyshsky district. Thus, in the territory of the region there is a unique opportunity to study the population variability of S. capillata, as in other regions it often grows together with closely related species and hybridizes with them (in the west with S. sareptana A. Beck., and S. praecapillata Alech., and in the south and east - with S. grandis P. Smirn, S. krylovii Roshev and S. baicalensis. The problem of the volume and boundaries of S. capillata L. is caused by its wide distribution from Spain to Yakutia and high
polymorphism. Many authors accepted the different limits of variability in the characteristics of S. capillata, which makes it
difficult to define this taxon, for instance, in almost all the floristic revisions the authors suggest, that the node of generative
shoot is hidden by the leaf sheathes because of the leaf sheath is longer than the internode, and only N.N. Tsvelev (Tzvelev, 1976) and H. Freitag (Freitag, 1985) admit that a node within this species can be exposed.
The purpose of our study was to research the population variability of S. capillata on the territory of the Altai in order to specify the limits of its features variation. 242 individuals of S. capillata belonging to 11 populations were involved in the analysis. The paper presents the result of statistical analysis by 26 quantitative and 2 qualitative features. A description of the lemma ultrastructure is also given. On the basis of the analysis, a refined morphological description of the species is given and the limits of variability of characteristics are indicated. It has also been established that some individuals with trichomes up to 0.15 mm on the tip of lemma, as well as individuals with closed nodes can be found within S. capillata species. It rejects themorphological pattern, accepted for S. capillata earlier. Despite the significant broadening of the boundaries of the variability of the signs, morphological differentiation was not revealed. All objects included in the analysis form a single cluster and belongto one general population. Also, the article provides information on the ecologo-cenotic association and distribution of thisspecies based on the revision of herbarium collections stored in AA, BM, E, GAT, K, KAS, KRA, KUZ, LE, M, MW, MHA, TK, NS, NSK,UPS.
The micromorphological features of the lemma were investigated in Trisetum and related genera in Pooideae (Poaceae) using scanning electron microscopy to evaluate the circumscription of the genus Trisetum and its systematic relationships. Seventy six species were studied including 32 species of Trisetum and selected species of Amphibromus (1 sp.), Avena (2 spp.), Avenula (6 spp.), Deschampsia (6 spp.), Dielsiochloa (1 sp.), Graphephorum (2 spp.), Gymnachne (1 sp.), Helictotrichon (8 spp.), Koeleria (5 spp.), Leptophyllochloa (1 sp.), Peyritschia (4 spp.), Raimundochloa (1 sp.), Relchela (1 sp.), Rhombolytrum (1 sp.), Rostraria (1 sp.) and Sphenopholis (3 spp.). The results showed that the epidermis of the lemma varies very little within the studied genera, thus it is a good character for the generic circumscription and to study the generic relationships in Pooideae. Trisetum is characterized by rectangular long cells, silica cells usually present, stomata absent, and hooks and prickle hairs present. Differences in the presence of silica cells, prickle hairs and various other epidermal features showed that Peyritschia is distinct from Trisetum. Species of Peyritschia generally lack silica cells, macrohairs and prickle hairs. Silica cells and prickle hairs are usually present in Trisetum and some species have macrohairs covering the lemma. Species examined of Sphenopholis have epidermal cells shorter than species of Trisetum and some species of Sphenopholis have stomata in the apical portion of the lemma. The results suggest that Sphenopholis interrupta (= Trisetum interruptum) should be excluded from Trisetum and classified in the genus Sphenopholis. Deschampsia is very distinct from Trisetum in the epidermal characteristics of the lemma. Studied species of Deschampsia have very long epidermal cells, absence of silica cells, prickle hairs and hooks usually absent, and long cells with straight anticlinal walls. The genera Amphibromus, Avena, Avenula, Helictotrichon, Gymnachne, Rhombolytrum, Dielsiochloa, Leptophyllochloa, and Raimundochloa showed various combinations of micromorphological features supporting their generic distinction among them and from Trisetum. On the other hand, Graphephorum, Rostraria and Koeleria are very similar to Trisetum in the epidermal characters of the lemma.
Descriptive “keys”, including definitions and explanatory diagrams, are given for the standardization and simplification of anatomical descriptions of the epidermides of grass leaf blades as seen in surface view. About 340 characters of the epidermis are included with ample room for expansion. Notes on variation and taxonomic importance of the characters are also included.
Barkworth, M. E. & Torres, M. A.: Distribution and diagnostic characters of Nassella ( Poaceae: Stipeae ). – Taxon 50: 439–468. 2001. – ISSN 0040‐0262.
Nassella sensu lato includes 116 species, making it one of the largest genera in tribe Stipeae. Argentina has the largest number of species, 72, with the greatest concentration being in the northwestern part of the country. Bolivia, Chile, and Uruguay have 26, 27, and 27 species, respectively. Other South American countries in which the genus is present are Brazil (18 species), Colombia (8), Ecuador (9), Paraguay (4), Peru (18), and Venezuela (2). Guatemala has two species, but Costa Rica only one. Mexico has eight native species, five of which also grow in the United States. One additional species grows in both the United States and Canada. Sixty species are known only from one country; one species, N. mexicana, grows in eight countries. Several new distribution records are documented: N. caespitosa, N. elata, N. leptothera and N. punensis for Bolivia, N. pauciciliata and N. spegazzinii for Brazil, N. airoides, N. argentinensis, N. spegazzinii for Paraguay, and N. tucumana (= N. asperifolia ) for Peru. Three new combinations are presented: N. burkartii, N. ligularis, and N. quinqueciliata. Two recently transferred species, N. barrancaensis and N. brachychaeta, are excluded from the genus and N. asperifolia, N. bonariensis, and N. amethystina are placed in synonymy. Tables summarising the distribution of Nassella and its morphological variation are presented.
A scanning electron microscopical survey of the lemma epidermal features in the 17 North American species of Melica and selected species of Briza, Catabrosa, Glyceria, Neostapfia, Pleuropogon, and Schizachne is presented. Melica is characterized by the universal presence of numerous hooks (=barbs, crown, or crochet cells of authors) alternating with long cells with straight to slightly undulating walls. Prickles also occur in all taxa, but their size, shape, and abundance were variable, both between and, in one case, within species. Macrohairs and stomatal complexes were occasionally observed on species of Melica, but silica bodies were not found on any of the species. Lemma epidermal features of Briza, Catabrosa, Glyceria, Pleuropogon, Schizachne, and Neostapfia suggest that Melica, Catabrosa, Glyceria, and Pleuropogon may be closely related but that the genera Briza, Schizachne, and Neostapfia are distinct from this group.
Stipa section Regelia comprises three species occurring in mountainous areas of Central Asia. One of them, S. smithii, was described by Martinovský in 1970, but the taxon has been overlooked in later taxonomical studies. The species was described with two varieties, var. smithii and var. macrocarpa. As a result of our taxonomical studies, we find the typical variety of the taxon to be conspecific with Stipa aliena, and propose that the second one be recognized as Stipa aliena var. macrocarpa comb. nov. Remarks on species belonging to section Regelia and micromorphological patterns of their lemma morphologies are discussed. A key to species close to S. aliena is provided.
The Stipeae tribe is a group of 400−600 grass species of worldwidedistribution that are currently placed in 21 genera. The ‘needlegrasses’ are characterizedby having single-flowered spikelets and stout, terminally-awned lemmas. We conducted a molecular phylogenetic study of the Stipeae (including allgenera except Anemanthele) using a total of 94 species (nine species were used asoutgroups) based on five plastid DNA regions (trnK-5’matK, matK, trnHGUG-psbA,trnL5’-trnF, and ndhF) and a single nuclear DNA region (ITS). Our parsimonyanalysis of DNA sequences supports: the monophyly of the Stipeae including Macrochloa as sister to all other Stipeae; the removal of Lorenzochloa erectifoliafrom Ortachne since it does not align with Ortachne but with some species of Anatherostipa; Ptilagrostis as occurring in two separate clades; and Oryzopsis asperifoliaas a monotypic genus. Achnatherum and Piptatherum as currently circumscribed are polyphyletic and we provide good support to split the formerinto fo
We conducted a molecular phylogenetic study of the tribe Stipeae using nine plastid DNA sequences (trnK-matK, matK, trnH-psbA, trnL-F, rps3, ndhF, rpl32-trnL, rps16-trnK, rps16 intron), the nuclear ITS DNA regions, and micromorphological characters from the lemma surface. Our large original dataset includes 156 accessions representing 139 species of Stipeae representing all genera currently placed in the tribe. The maximum likelihood and Bayesian analyses of DNA sequences provide strong support for the monophyly of Stipeae; including, in phylogenetic order, Macrochloa as remote sister lineage to all other Stipeae, then a primary stepwise divergence of three deep lineages with a saw-like (SL) lemma epidermal pattern (a plesiomorphic state). The next split is between a lineage (SL1) which bifurcates into separate Eurasian and American clades, and a lineage of three parts; a small Patis (SL2) clade, as sister to Piptatherum s.str. (SL3), and the achnatheroid clade (AC). The AC exhibits a maize-like lemma
Stipa klimesii sp. nov. from the Western Himalayas (India: Ladakh) and its variety S. klimesii var. pubescens var. nov. are described. The
new species is similar to S. roborowskyi but differs by its longer anthecium, longer ligules of vegetative shoots, longer hairs on seta and
shorter awns. Stipa klimesii is also similar to S. purpurea, but differs by longer ligules of vegetative shoots, shorter awns, slightly shorter
hairs on seta and by the character of the panicle, which is compressed and with straight branches in S. klimesii vs. lax and with flexuous
branches in S. purpurea. Epidermal patterns of the lemma in S. klimesii and both above-mentioned species, were examined by scanning
electron microscopy. Images of macromorphological and micromorphological structures are provided.
Morphological investigations were conducted on four taxa of the Stipa tianschanica complex occurring in Central Asia. The main objective of the study was to survey the micromorphological characters of the lemma in the complex by means of scanning electron microscopy (SEM) in order to assess their taxonomic value and to compare the variation with the recent treatment based on macromorphological traits. The main lemma epidermal characters studied included the frequency, shape and distribution of long cells, hooks, prickles and macrohairs. A principal component analysis of macromorphological traits revealed correlations with micromorphological characters and with the geographical distribution of the specimens examined. On this basis, three species, namely S. tianschanica, S. klemenzii and S. austromongolica, and one additional subspecies, S. tianschanica subsp. gobica, are recognized in Central Asia. Stipa austromongolica is described here as a species new to science. The lectotype for S. tianschanica is designated here as well. Morphological descriptions, synonyms, distribution maps, citations of representative specimens and an identification key are provided.
The Stipa section Smirnovia Tzvel. includes 32 taxa. Of this number, 18 taxa, with glabrous (smooth or scabrous) awn columns, belong to the Stipa lipskyi group, which is the object of the present study. The centre of diversity of the studied group is located in the mountains of Middle Asia (Pamir Alai and Tian-Shan). Based on the examination of a large number of herbarium specimens (over 550 sheets), field observations, scanning electron microscopy observation of lemma micromorphology and statistical analysis of macromorphological characters, 12 taxa at the specific level were recognized on the area studied. Three species of hybrid origin, Stipa × tadzhikistanica M. Nobis, S. × brevicallosa M. Nobis, and S. × hissarica M. Nobis, as well as the variety S. lipskyi var. pilosivaginata M. Nobis, were described as new to science. Additionally, lectotypes for S. karataviensis Roshev. and S. longiplumosa Roshev. were designated and a new combination Stipa macroglossa subsp. kazachstanica (Kotuch.) M. Nobis was proposed. Numerous new localities, often far from the previously known distribution area, were reported for several species. Illustrations and a key to species and varieties are provided in addition to complete descriptions including information on nomenclatural types, synonymies, distributions, habitat and specimens examined.
The Distichlis clade comprises Distichlis (7 species), Monanthochloë (2), and Reederochloa (1). All species except D. distichophylla (endemic to Australia) and D. spicata (widespread in the New World) are restricted either to North or South America. We investigated phylogenetic relationships within the clade using chloroplast (trnL-F and ndhF) and nuclear ribosomal (internal transcribed spacers and 5.8S) DNA sequences. We also studied lemma micromorphology, leaf blade anatomy, macromorphology, and biogeography in a phylogenetic context. The Distichlis clade is strongly supported in the molecular analyses. A morphological synapomorphy for the clade is the presence of a single papilla on the center of each subsidiary cell of lemma stomata. Other diagnostic features include dioecy, rhizomes or stolons, conspicuously distichous leaves, 5-13 lemma nerves, dumbbell- or flask-shaped bicellular microhairs with sunken basal cells, and growth in alkaline or saline soils. The nuclear and chloroplast phylogenies indicate that Monanthochloë and Reederochloa are nested within a paraphyletic Distichlis, and a number of structural characters, including leaf blade length, number of spikelets per inflorescence, and number of florets per spikelet, also fall within the range of variation in Distichlis. Therefore, we propose expanding the circumscription of Distichlis to include Monanthochloë and Reederochloa, and make the following new combinations: Distichlis acerosa, D. eludens, and D. littoralis. Biogeographical analysis revealed that the group likely originated in North America followed by a number of long-distance dispersal events, including back dispersals.
Micromorphological features of the leaf-blade, lemma, and palea were examined under scanning electron microscopy (SEM) for
64 species of the genus Festuca L. occurring in the Iberian Peninsula. The objective of the study was to survey these characters for the first time in the
whole of the genus Festuca in this region, to assess their taxonomic value, and to compare the variation with recent DNA sequence-based phylogenies.
The principal features include the frequency, shape, and distribution of silica bodies, short cells, crown cells, and prickles,
and the morphology of long cells. The abaxial lemma surface shows the most important taxonomical and phylogenetic characters.
The variation observed was consistent with the subgenera and sections identified in molecular studies.
Morphological study of fossil grass anthoecia of Berriochloa and Nassella collected from Miocene-Pliocene strata in Kansas has revealed well-preserved epidermal structure. This seems to be the first micromorphological information known from fossil grass floral bracts. The epidermal pattern on the lemma in the fossils and their living counterparts are evidence in support of the view that the North American species of Stipa of the section Hesperostipa Elias and species of Piptochaetium have a common ancestry in Berriochloa, and that species of both taxa have been distinct from species of the Nassella, Oryzopsis, and other Stipa since at least the Miocene or Pliocene.
In the genus Achnatherum P. Beauv., a new section Piptatheropsis Tzvelev sect. nova is described with a type A. caragana (Trin.) Nevski, and a new combination A. sect. Regelia (Tzvelev) Tzvelev comb. nova is proposed. In the genus Stipa L., the species S. capensis Thunb. (sect. Stipella Tzvelev) is separated in a new genus Stipella (Tzvelev) Tzvelev comb. et stat. nov.; a new species Stipa boczantzevii Tzvelev sp. nova from Middle Asia is described; two species, S. iljinii Roshev. (= S. adoxa Klokov) and S. nikitinae Tzvelev (= S. violacea Nikitina, non Hitchc.), are restored; the taxonomy of species from S. zalesskii Wilensky affinity is clarifited, a new section S. sect. Hemibarbatae Tzvelev sect. nova is described.
The apical portion of paleas of the perfect (upper) floret of 11 species of Dichanthelium, 10 species of Panicum, and one species of Echinochloa were examined with a scanning electron microscope. The surfaces of the Dichanthelium palea tips uniformly had simple, rounded papillae, widely spaced in regular rows, whereas the palea tips of most Panicum species had irregularly arranged, compound or aggregated papillae. Unusual epidermal features were observed in P. obtusum, P. hians, and P. hemitomon. The Echinochloa crusgalli palea surface exhibited a pattern of papillae or spicule development similar to that of P. hians. Transverse sections of Dichanthelium palea showed the papillae to be little if at all thickened. An electron beam x-ray microanalysis indicated a high concentration of silicon in the papillae.
Micromorphological features of the lemma were investigated in the subtribe Eleusininae (Poaceae) using scanning electron microscopy. Ninety-two taxa were studied, which included 48 genera and all currently recognized species of Leptochloa s.l. All species of Leptochloa and a majority of genera in Eleusininae have cork cells, but silica cells are mostly absent in Leptochloa and most related genera in Eleusininae. Enneapogonoid-type microhairs are reported for Cladoraphis cyperoides and Psammagrostis wiseana, representing only the second report in Eleusininae. Although bicellular microhairs occur in most taxa, variations in microhair type, coupled with the occurrence of partitioning membranes, give them supra-specific phylogenetic utility. The occurrence of papillae on short and long cells varies within Leptochloa and between genera. Prickles are ubiquitous in Leptochloa and most related genera. Macrohairs are present in all species of Leptochloa but absent in some related genera. Clavicorniculate macrohairs are reported for one species each of Leptochloa and Coelachyrum, and a corniculate macrohair was observed in Cynodon. A crispate macrohair occurring in three species of Coelachyrum is described for the first time and probably represents a synapomorphy in that genus. The analysis of Leptochloa suggests that micromorphological characters vary little within a genus, and thus have the potential to serve as phylogenetic markers at the generic level. Uncertainty concerning the homologous relationships of papillae, hooks, prickles, and macrohairs is discussed in light of this study and previous literature.
Scanning electron microscopy of lemma surfaces revealed five major types of vestiture in annual Muhlenbergia species: villous macrohairs, swollen base macrohairs, prickle hairs, bicellular microhairs, and papillae. Size, wall thickness, undulation characteristics of the epidermal long cells, and specific location, shape, and arrangement of the five vestiture types are of systematic utility. Lemma micromorphological features, when employed with other macromorphological characters, indicate the presence of 10 groups in the annual Muhlenbergia.
Abaxial epidermes of basal leaves of 49 species of Stipeae, almost all North American, were examined. It was not possible to recognize individual species by their epidermal characters but some taxonomically interesting correlations were found. Shape of costal silica bodies and numbers of costal and intercostal cell files were the most useful taxonomic characters. Most species had dumbbell- to nodulose-shaped costal silica bodies but a few species, notably Stipa pennata and members of S. sect. Hesperostipa, had bodies that were rectangular in outline. Species of Oryzopsis generally had fewer silica body-containing costal cell files and smoother long-cell walls than most species of Stipa. Species of Piptochaetium examined had relatively few silico-suberose pairs in the intercostal region and a relatively high number of costal cell files with silicose cells.
Stipa narynica M. Nobis sp. nov. from the western Tian-Shan Mts (western Kyrgyzstan) is described and illustrated. The new species belongs to sect. Smirnovia Tzvel. Morphologically the species is similar to S. aktauensis, a species from which it is easily distinguished by its longer glumes (41–)44–55(–62) mm vs 35–45 mm, longer anthecium (11.5–) 12.0–14.2(–14.8) mm vs 9.5–11.2(–11.7) mm, longer hairs on the seta (5.5–)6.0–8.0(–8.5) mm vs (3.0–)3.8–5.5(–6.0) mm and by the top of the lemma which in S. narynica is either glabrous or with a poorly developed ring of short hairs, while in S. aktauensis, the top of lemma is always distinctly and densely pilose. The lemma and leaf blade structure of both species were examined by means of SEM. The main features differentiating S. narynica and S. aktauensis and distribution of the taxa are presented. An original key to the middle Asiatic species of the sect. Smirnovia, the most similar to Stipa narynica is provided.
Stipa zeravshanica M. Nobis sp. nov. from the western Pamir Alai Mts (Tajikistan) is described and illustrated. Morphologically, the new species is similar to S. gracilis, but it is easily distinguishable by pilose (vs. glabrous) lower part of the awn, and generally somewhat longer ligules of the vegetative shoots. Epidermal patterns of the lemma in S. zeravshanica and three other closely related taxa, namely S. gracilis, S. himalaica and S. orientalis, were examined by means of SEM. The main macro-morphological and micro-morphological characteristics differentiating all mentioned species are presented. Additionally, a lectotype for S. gracilis is designated. Based on phytosociological relevés prepared during field investigation in the western Pamir Alai Mts, a new plant association Asperulo albiflorae–Stipetum zeravshanicae, occurring on shelves and rocky crevices is also described.
The tribe Stipeae with an estimated number of ca. 600 species is part of the grass subfamily Pooideae and has near worldwide distribution. Its species are often dominant constituents of steppe vegetation and other grasslands, especially in Eurasia, the Americas and Australia. The taxonomy of Old World Stipeae has been studied to date primarily on the basis of morphology and anatomy, while existing molecular phylogenetic investigations have mainly dealt with New World or Australian taxa. We studied 109 new ingroup taxa with a focus on Old World Stipeae (in addition with an extensive outgroup sampling) using chloroplast and nuclear ribosomal DNA sequences (3′trnK region, ITS1–5.8S gene–ITS2), and discuss taxonomic key characters. Five highly supported monophyletic lineages were identified, some of which were rather unexpected: (a) the narrowly defined Stipa core clade, which is primarily Eurasian but extends into Africa north of the Sahara Desert, (b) the majority of Old World Piptatherum, (c) a “Transcontinental Stipeae Clade” encompassing Eurasian, African, American and Australian lineages, (d) a Himalayan to E Asian clade and (e) the single species Achnatherum splendens. The large “Transcontinental Stipeae Clade” contained several lineages of Eurasian Stipeae different from the Stipa core (a), i.e., genera Aristella, Celtica, Oloptum gen. nov., Stipella stat. et. gen. nov., species of Achnatherum, and the species-rich lineages of Nassella/Jarava in America and of Austrostipa in Australia. In our circumscription Ptilagrostis was nested in (d), a clade (which included some species of Achnatherum and poorly studied Himalayan species ascribed to either Stipa or Orthoraphium) and whose internal structure remained unclear. Oloptum, gen. nov., is described, and the following combinations are made: Achnatherum pelliotii, comb. nov., Aristella keniensis, comb. nov., Oloptum miliaceum, comb. nov., Stipella, stat. et. gen. nov., S. capensis, comb. nov., S. nitens, comb. nov., S. parviflora, comb. nov., S. staintonii, comb. nov., and S. tigrensis, comb. nov.
A B S T R A C T The apical portion of paleas of the perfect (upper) floret of 11 species of Dichantlieliurn, 10 species of Panicum, and one species of Echinochloa were examined with a scanning electron microscope. The surfaces of the Dichanthelium palea tips uniformly had simple, rounded papillae, widely spaced in regular rows, whereas the palea tips of most Panicum species had irregularly arranged, compound or aggregated papillae. Unusual epidermal features were observed in P. obtusum, P. Itians, and P. hemitomon. The Ecliinochloa crusgalli palea surface exhibited a pattern of papillae or spicule development similar to that of P. hians. Transverse sections of Dichanthelium palea showed the papillae to be little if at all thickened. An electron beam x-ray microanalysis indicated a high concentration of silicon in the papillae. PANICUM L. IS ONE of the largest of the grass genera, with over 500 species commonly recognized in the floras of the world. Hitchcock and Chase (1910) listed 197 species for North America, but with the transfer of the subgenus Paurochaetium species to Setaria (Rominger, 1962) the grouping of the Panicum geminatum and P. paludivagum taxa in the genus Paspalidium of Stapf, and the recent elevation of the Dichanthelium subgenus to generic status (Gould, 1974), the number is reduced to less than 75. Preliminary investigations indicate that two other species, Panicum hians Ell. and P. hemitomon Schult., also will be eventually removed from the genus.
The taxonomic position and distribution of Stipa tianschanica Roshev, a species new to the flora of Tajikistan (central Asia), are discussed. Its morphological characters are compared with other members of the S. tianschanica complex and information on their taxonomy and distribution are presented. The distinguishing features of S. tianschanica subsp. tianschanica, S. tianschanica subsp. gobica (Roshev.) D. F. Cui and S. klemenzii Roshev. are presented in a table, together with photographs of their lemma surfaces and a list of their synonyms. Analysis of the morphological characters of the taxa provides new information on their variability and a new combination, S. tianschanica subsp. gobica var. pubescens (Hanelt & Davažamc) M. Nobis comb. nov., is proposed. A key to the taxa of Stipa sect. Smirnovia Tzvel. occurring in Tajikistan (especially in the area of Pamirs), a description of S. tianschanica subsp. tianschanica and illustrations of the most important diagnostic characters of the taxon are included.
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