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The carpology of the Chenopodiaceae with reference to the phylogeny, systematics and diagnostics of its representatives

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... The family Chenopodiaceae Vent. comprises ~1500 species distributed worldwide (Sukhorukov 2014). It is divided into several subfamilies and at least one third of them belong to the core subfamily Chenopodioideae in the tribes Axyrideae G. Kadereit (Kadereit et al. 2003(Kadereit et al. , 2010Zacharias and Baldwin 2010;Fuentes-Bazan et al. 2012a, 2012b. ...
... It has become apparent in recent years that fruit and seed characters are also useful in distinguishing members of the former Chenopodium, particularly amongst groups that are quite morphologically similar (Sukhorukov 2006(Sukhorukov , 2014Sukhorukov et al. 2015a). A good example is Chenopodium gubanovii Sukhor. ...
... et Uotila] based on molecular phylogenetic data supported by morphological and seed characters. Almost all Chenopodieae (Archiatriplex, Chenopodium, Chenopodiastrum, Exomis, Holmbergia, Lipandra, Manochlamys, Microgynoecium, Proatriplex and all Atriplex with red or black seeds) possess a seed-coat testa with thickened outer cell walls impregnated with vertical or oblique stalactites and a reduced protoplast (hereafter 'stalactite seed coat') (Sukhorukov 2006;Kadereit et al. 2010;Sukhorukov 2014). There are a few exceptions, however, for example the seed coat in Halimione and three Chenopodium species endemic to Juan Fernández Archipelago (Chile) (C. ...
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The former Chenopodium subgen. Blitum and the genus Monolepis (Chenopodioideae) are characterised in part by a reduced (0–4) number of perianth segments. According to recent molecular phylogenetic studies, these groups belong to the reinstated genera Blitum incl. Monolepis (tribe Anserineae) and Oxybasis (tribe Chenopodieae). However, key taxa such as C. antarcticum, C. exsuccum, C. litwinowii, C. foliosum subsp. montanum and Monolepis spathulata were not included and so their phylogenetic position within the Chenopodioideae remained equivocal. These species and additional samples of Blitum asiaticum and B. nuttallianum were incorporated into an expanded phylogenetic study based on nrDNA (ITS region) and cpDNA (trnL-trnF and atpB-rbcL intergenic spacers and rbcL gene). Our analyses confirm the placement of C. exsuccum, C. litwinowii and C. foliosum subsp. montanum within Blitum (currently recognised as Blitum petiolare, B. litwinowii and B. virgatum subsp. montanum, respectively); additionally, C. antarcticum, currently known as Oxybasis antarctica, is also placed within Blitum (reinstated here as B. antarcticum). Congruent with previous studies, two of the three accepted species of Monolepis – the type species M. trifida (= M. nuttalliana) as well as M. asiatica – are included in Blitum. The monotypic genus Carocarpidium described recently with the type C. californicum is not accepted as it is placed within Blitum (reinstated here as B. californicum). To date, few reliable morphological characters have been proposed that consistently distinguish Blitum (incl. two Monolepis species) from morphologically similar Oxybasis; however, two key differences are evident: (1) the presence of long-petiolate rosulate leaves in Blitum vs. their absence in Oxybasis and (2) a seed coat structure with the outer wall of the testa cells lacking stalactites (‘non-stalactite seed coat’) but with an obvious protoplast in Blitum vs. seed coat with the outer walls of the testa cells having stalactites (‘stalactite seed coat’) and a reduced protoplast in Oxybasis. Surprisingly, the newly sequenced North American Monolepis spathulata nested within the tribe Dysphanieae (based on ITS and trnL-trnF + rbcL + atpB-rbcL analyses).The phylogenetic results, as well as presence of the stalactites in the outer cell walls of the testa and lack of the rosulate leaves, confirm the distinctive nature of Monolepis spathulata from all Blitum and, therefore, the recent combination Blitum spathulatum cannot be accepted. Indeed, the morphological and molecular distinctive nature of this species from all Dysphanieae supports its recognition as a new monotypic genus, named herein as Neomonolepis (type species: N. spathulata). The basionym name Monolepis spathulata is also lectotypified on a specimen currently lodged at GH. Finally, while Micromonolepis pusilla is confirmed as belonging to the tribe Chenopodieae, its position is not fully resolved. As this monotypic genus is morphologically divergent from Chenopodium, it is retained as distinct but it is acknowledged that further work is required to confirm its status.
... Morphological characters vary drastically between Dysphania species, e.g. perianth concrescence in closely related species (Uotila 2013) or presence of both vertical and horizontal seeds within an individual (Sukhorukov 2014;Sukhorukov et al. 2015). The defining generic traits for Neobotrydium according to Zhang and Zhu (2016) are not in fact present in some species of this genus (Sukhorukov 2014). ...
... perianth concrescence in closely related species (Uotila 2013) or presence of both vertical and horizontal seeds within an individual (Sukhorukov 2014;Sukhorukov et al. 2015). The defining generic traits for Neobotrydium according to Zhang and Zhu (2016) are not in fact present in some species of this genus (Sukhorukov 2014). Besides, the tribe Dysphanieae (Pax) Pax is not closely related to Chenopodium (tribe Chenopodieae), as confirmed by extensive molecular and carpological data (Fuentes-Bazan, Mansion, and Borsch 2012; Kadereit et al. 2010;Sukhorukov 2014;Sukhorukov and Zhang 2013). ...
... The defining generic traits for Neobotrydium according to Zhang and Zhu (2016) are not in fact present in some species of this genus (Sukhorukov 2014). Besides, the tribe Dysphanieae (Pax) Pax is not closely related to Chenopodium (tribe Chenopodieae), as confirmed by extensive molecular and carpological data (Fuentes-Bazan, Mansion, and Borsch 2012; Kadereit et al. 2010;Sukhorukov 2014;Sukhorukov and Zhang 2013). Some characters evolved in Chenopodieae and Dysphanieae are clearly homoplasies, e.g. ...
Article
The distribution of Elytraria acaulis (Acanthaceae), the most widely distributed species of the genus in Africa, is expanded to include two further tropical West African countries, Benin and Togo. Silene melitensis (Caryophyllaceae) is reported for the first time from northern Africa. Arthrocaulon franzii (Chenopodiaceae-Amaranthaceae) is reported for the first time for Senegal. Two new combinations are proposed within Hypertelis (Molluginaceae): H. namaquensis and H. pusilla previously treated within Mollugo and Pharnaceum. The newly described Neobotrydium burundiense (Chenopodiaceae-Amaranthaceae) is synonymized with Dysphania congolana, a species native to west-central tropical Africa. The genera Neobotrydium, Ambrina and Roubieva are treated here as congeneric with Dysphania. Several new alien species are recorded for the African flora: Amaranthus standleyanus (Amaranthaceae s.str.) found in Sal Island (Cape Verde) is new for tropical Africa, and Dysphania pumilio (Chenopodiaceae-Amaranthaceae) is reported from DR Congo (new for west-central Africa). Bassia indica (Chenopodiaceae-Amaranthaceae) is cited from Kenya and Tunisia, and its invasive status is confirmed for northern Africa. Kalanchoe daigremontiana, K. delagoensis, K.×houghtonii, and K. fedtschenkoi (Crassulaceae) are ergasiophytes in Tunisia, each with a different invasion status. A key to the non-native Kalanchoe species found in Tunisia is provided.
... In my opinion, this lectotype designation was a premature decision, because of the considerations that follow. First, Sukhorukov probably has not seen the real protologue and original description of S. controversa, because Flora Sicula (Lojacono Pojero, 1904) is not cited anywhere in his book (Sukhorukov, 2014), while no description of the species was provided by Nyman, who simply cited the name S. controversa there is no doubt that the name S. squarrosa is valid. The plant was collected in the island of Naxos (Greece). ...
... No nomenclatural combination in Salsola is currently was accumulated for many years, but already in 1899 Churchill was unable to add specimens to his collection because of his failing health (see relevant details in Hemsley, 1906). Thus, it is evident that Lojacono Pojero has never seen the specimen K000899539 (the lectotype designated by Sukhorukov, 2014) and did not use it when he was preparing the validating description of S. controversa in Flora Sicula. In contrast, Lojacono Pojero evidently used the collections of the Herbarium Siculum in Palermo (now Herbarium Mediterraneaum Panormitanum, PAL) until 1913, when he left Palermo (Domina et al., 2014). ...
... Thus, the only reasonable option under Art. 9.19 of ICN (McNeill et al., 2012) is to have that lectotypification (Sukhorukov, 2014) superseded because of its evident and serious enough conflict with the protologue (Art. 9.19(b) of ICN: McNeill et al., 2012) and to select another lectotype among several specimens from PAL, which perfectly match the original detailed description provided by Lojacono Pojero (1904). ...
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Current and historical views on taxonomy and nomenclature of Pontic-Mediterranean coastal and some Australasian taxa of Salsola (Chenopodiaceae) are analyzed. Taxonomic identity and nomenclature of several names applied and misapplied to members of the species group known in recent publications mainly as Salsola pontica (Pall.) Degen sensu lato are discussed. It is demonstrated that Kali dodecanesicum C. Brullo & al. is a later synonym of Salsola squarrosa Steven ex Moq., which appears to be the earliest species-rank name available for the whole Pontic-Mediterranean group of taxa. This group is represented by Western Mediterranean (S. controversa Tod. ex Lojac.), Eastern Mediterranean (S. squarrosa s. str.), and mainly Pontic (S. pontica s. str.) geographical races. Considering the blurred morphological and geographical limits between these taxa, they are better treated as three subspecies of S. squarrosa: subsp. controversa (Tod. ex Lojac.) Mosyakin, comb. nov., subsp. squarrosa, and subsp. pontica (Pall.) Mosyakin, comb. nov., respectively. It is demonstrated that S. macrophylla R. Br. (described from Australia) is not conspecific with any of Pontic-Mediterranean coastal taxa but is probably related to the currently recognized species S. australis R. Br. The identity of S. brachypteris Moq. (described from Java, Indonesia) remains uncertain but, judging from available evidence, it is most probably either related to or conspecific with S. macrophylla, or some other insufficiently known Australasian species. The problem of conflicting typifications and application of the name S. caroliniana Walter is briefly discussed; it is concluded that the name should be proposed for rejection. The need for further morphological, molecular phylogenetic, and phylogeographic studies of coastal Eurasian and Australasian species of Salsola is emphasized. See also the companion PPT presentation: https://www.researchgate.net/publication/321778932_Taxonomy_and_nomenclature_of_Pontic-Mediterranean_and_some_Australasian_taxa_of_Salsola_sstr_Chenopodiaceae_problems_and_solutions
... t. 55"] and indicated geographical data for the species ("Habitat in Tartariae ad Wolgae ripam, inque desertis note, in which Linnaeus expressed his doubts regarding the status of "Corispermum spicis squarrosis" as a species sufficiently distinct from "Corispermum floribus lateralibus" (now known as C. hyssopifolium) is important. Any species of Agriophyllum, even without fruits and even in times of Linnaeus when authors often adhered to a rather broad species concept, cannot be confused with a species of Corispermum, or with C. hyssopifolium in particularthere are too many obvious morphological characters distinguishing members of these two currently recognized genera (see e.g., Iljin 1929, Kühn 1993, Sukhorukov 2014). In our opinion, the description itself, and especially the final note, definitely indicate that Linnaeus, when describing C. squarrosum, had at his disposal only a herbarium specimen (or specimens) and/or cultivated plants of a true Corispermum, not of Agriophyllum. ...
... The fruits are completely or almost completely covered by bracts. The specimen LINN 12.3 morphologically corresponds to the species of Corispermum occurring in the easternmost regions of Europe and probably adjacent southwestern parts of Siberia and northwestern Kazakhstan ( Mosyakin 1996, Sukhorukov 2014) and known in literature as: In the case of selecting the specimen LINN 12.3 as the lectotype, the name Corispermum squarrosum will be applied to a rather little-known and geographically restricted species of Corispermum sensu stricto. This, however, will most accurately follow the understanding of the species by Linnaeus. ...
... (= C. squarrosum) will be the correct name for the species of the true Agriophyllum, also known as A. arenarium and/or A. pungens. Despite the application of the name A. squarrosum to that species in recent taxonomic and floristic treatments ( Ball 1964, Gusev 1996, Zhu et al. 2003, Lomonosova 1992, Menitskiy 2012, Tzvelev 2012), this usage was not universal, and many other authors used different names, especially A. arenarium ( Fenzl 1851, Bunge 1879, 1880, Richter 1890, Volkens 1893, Schmalhausen 1897, Iljin 1930, 1936, 1937, Hernández-Ledesma et al. 2015) and recently also A. pungens ( Grubov 1966, Sukhorukov & Akopian 2013, Sukhorukov 2014). Considering the complex history of application and misapplication of the name C. squarrosum to several species of Corispermum, it is our view that the best solution would be to reject the confusing "Pallas-Moquin-Aellen's" concept of C. squarrosum and to end that story for the typical Agriophyllum species with the correct name A. pungens. ...
Article
The Linnaean name Corispermum squarrosum (Chenopodiaceae, Corispermeae) is lectotypified here by the specimen LINN 12.3. This specimen is identifiable with the plant currently known as C. uralense, a species occurring in southeasternmost regions of Europe and adjacent parts of Siberia and Kazakhstan, and the name C. squarrosum should be now applied to it. Our lectotypification of C. squarrosum restores the original taxonomic application by Linnaeus to an East European species of Corispermum. It is demonstrated that the epithet "squarrosum" was misapplied to several species of Corispermum and one species of Agriophyllum. This long-standing nomenclatural confusion was initiated by Pallas, who, contrary to Linnaeus, considered a species of Agriophyllum as "the only true C. squarrosum". That concept was then accepted by Moquin-Tandon and Aellen and followed by some other authors. Nomenclatural implications of the lectotypification of C. squarrosum are explained. As a result of our lectotypification, the most widespread species of Agriophyllum (widely known as A. arenarium and "A. squarrosum" sensu Moquin-Tandon), should be called A. pungens. The generic name Agriophyllum was not validly published by Marschall von Bieberstein in 1819 (provisional name), but it was validated by C.A. Meyer in 1831. Relevant updated nomenclatural citations are provided.
... The Chenopodiaceae is a large family within the order Caryo phyllales. It comprises ~ 1600 species and is divided into ~ 110 genera (Sukhorukov 2014, Hernández-Ledesma et al. 2015. It is mostly distributed in the arid regions of the World. ...
... This species is native and widely distributed in the northern deserts and steppes of temperate Asia. It is naturalized in Burundi (Reekmans 1980), Kenya and South Africa (Sukhorukov 2014), where it was probably introduced by migratory birds (Sukhorukov 2014). ...
... 3) The genus Dysphania has been segregated from Chenopodium , Fuentes-Bazán et al. 2012 only recently using molecular phylogeny, with clear support of carpological results (Sukhorukov & Zhang 2013). It comprises c. 50 representatives with the diversity centers in Australia, South and Central America and Pan-Himalaya (Sukhorukov 2014, Sukhorukov et al. 2015 The most common is the American D. ambrosioides (≡ Chenopodium ambrosioides L.), widely distributed elsewhere in the tropics and subtropics (Aellen 1928, Uotila 1988, Sukhorukov 2014, (Brenan 1954(Brenan , 1988. Despite the fact that Dysphania congolana is a wellrecognizable taxon with lobate or sinuate leaves, in contrast to other native genus members with pinnatifid or pinnatisect leaves, it is sometimes confused with the alien D. ambrosioides due to the similar leaf shape. ...
Article
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A new species Atriplex congolensis Sukhor. is described from the highlands of D.R.Congo and illustrated. It was previously cited as A. hastata L. (now A. prostrata Boucher ex DC.) and is the only species of Atriplex sect. Teutliopsis Dumort. emend. Sukhor. in tropical Africa. A morphological comparison of all Atriplex representatives encountered in Africa (A. chenopodioides Batt., A. congolensis Sukhor., A. davisii Aellen, A. nilotica Sukhor., A. patula L., A. prostrata Boucher ex DC., and A. verreauxii Moq.) is provided. All records of the rare native Dysphania congolana (Hauman) Mosyakin & Clemants in mountainous tropical Africa are mapped using previously known and re-identified locations. Oxybasis chenopodioides is newly reported for D.R.Congo. The lectotype of Chenopodium glaucum L. subsp. congolanum Hauman (Dysphania congolana) is designated. It is pointed out that D. congolana cannot be considered a close relative to any American taxon despite morphological similarities.
... However, in some plant groups two or more distinct (noncontinuous) diaspore morphs occur on one individual. Depending on the structures involved in the actual heteromorphism, this phenomenon is called heterospermy or heterocarpy (Hannan, 1980) or heteroanthocarpy (Sukhorukov, 2014), and it always results in a divergent germination strategy of the different morphs. Imbert (2002) reported the occurrence of seed heteromorphism in 18 angiosperm families. ...
... In several species of Salsoloideae, for example, the heteromorphic fruiting perianth significantly affects dispersal and germination behaviour (e.g. Salsola komarovii (Takeno and Yamaguchi, 1991), Salsola affinis (Wei et al., 2007), Salsola ikonnikovii (Xing et al., 2013), Salsola rubescens (El-Keblawy et al., 2014) and Halogeton glomeratus (Williams, 1960;Sukhorukov, 2014)). In Salsola volkensii, for example, chlorophyllous, fast germinating embryos and achlorophyllous, dormant embryos are developed on the same plant (Negbi and Tamari, 1963). ...
Article
Germination is a vulnerable and risky step in a plant’s life cycle. Particularly under harsh environmental conditions, where time windows favourable for seedling establishment and survival are short or unpredictable, germination speed might play a highly adaptive role. We investigated the germination speed of 107 Amaranthaceae s.l. at two different temperatures and related the results to various plant and habitat traits taking into account the molecular phylogenetic relatedness of the species sampled. Germination speed is a fast evolving trait in Amaranthaceae s.l. It evolves towards significantly faster optima in C4 and halophyte lineages, albeit for different reasons. While C4 photosynthesis and fast germination are simply traits beneficial under the same environmental conditions, saline habitats, especially in subtropical regions, seem to select for fast germination. Heterospermy is probably much more common than currently known in Amaranthaceae s.l. and likely evolved as a bet-hedging strategy in lineages with fast seed germination. The evolution of germination speed is neither related to seed mass, an evolutionary stable trait, nor dependent on plant longevity and plant height. Correlation analyses of climate variables and germination speed suggest that there is an indirect effect of climate which is dependent on the ecological niche of the species.
... This is reflected in regional floras (e.g., Sergievskaya 1961, Rebristaya 1966and Gudoshnikov 1971. Fedorova (2014) updated information for central European Russia at a regional level and Sukhorukov (2014) listed the provinces where it is known in European Russia. Lomonosova (1992) revised much Siberian material and prepared a distribution map for Flora Sibiriae. ...
... These specimens were evidently the best candidates for lectotypification; however, now they are regarded as possible isolectotypes of C. acerifolium. They also include seeds; the lectotype specimen at LE (Sukhorukov 2014) is only flowering. ...
Article
Chenopodium acerifolium Andrz. and C. karoi (Murr) Aellen have often been confused with each other and with similar taxa occurring in the northernmost parts of Russia. In particular their relationships with C. prostratum Bunge ex Herder nom. illeg. and C. jenissejense Aellen and Iljin have not been clear. The type material of C. jenissejense is heterogeneous and here we designate the lectotype for it so that C. jenissejense will be probably conspecific with C. prostratum, for which the lectotype is also designated here. We provisionally consider C. jenissejense, a Siberian riverside plant, to be conspecific with the mainly Central Asian C. karoi, but further studies are needed to confirm their relationships. Emended morphological descriptions are given of C. acerifolium and C. karoi and their types are discussed. Paul Aellen's role in the taxonomic treatment of C. karoi s. lato and in preparing the account of Chenopodium for the Flora of the USSR is clarified based on the correspondence between Aellen and M.M. Iljin.
Article
Atriplex, as the largest genus of the Chenopodiaceae, is well known for its taxonomic complexity resulting from overlapping morphological characters. This halophytic perennial is distributed in salty and dry soils of Eurasia, America and Australia. Atriplex is one of the most widely cultivated rangeland species in Iran, which improves and revitalizes the rangelands. These unique characteristics of Atriplex make it a valuable plant. The present study is the first micromorphological investigation of this genus in Iran. In this study, the molecular evidence, micromorphological and anatomical structure of four species of Atriplex have been considered to evaluate their relationships. The basic shape of the pollen grains in most taxa is subprolate, however prolate and spheroidal pollen grains were recorded for A. lentiformis and A. canescens. One type of trichome (glandular) is described. Here, among the glandular trichomes, density and size of trichomes are considered as valuable characteristics. Micromorphology of epidermis illustrated three types of epidermal cells including puzzle-shaped, polygonal and irregular. Stem cross sections showed rounded shape, but the margins are diff erent between four species. Using nuclear and plastid markers (nrDNA ITS and rpl32-trnL(UAG)), we reconstructed phylogenetic relationships within four species of Atriplex. This data set was analyzed by phylogenetic methods including Bayesian inference, maximum likelihood and maximum parsimony. In phylogenetic analyses, all members of four species formed a well-supported clade (PP = 1; ML/BS = 100/100), divided into three major subclades (I, II and III). The results of the present study showed the usefulness of micromorphological, anatomical and molecular characteristics in taxon delimitation at specific levels.
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For the first time, a list of alien plants registered on the territory of the Middle Volga Region (within the boundaries of Samara and Ulyanovsk Regions) is published. The alien flora of the Middle Volga Region is represented by 461 species of vascular plants belonging to 275 genera and 77 families (23.1% of the total flora). For each species information is provided about the time of occurrence in the flora (archaeophyte, neophyte), mode of introduction (xenophyte, ergasiophygophyte), invasive status (ephemerophyte, colonophyte, epecophyte, agriophyte), life form, geographical element, frequency of occurrence, range of occupied habitats, as well as the date of first mention. The predominance of neophytes (394 species, 85.5%) over archaeophytes (67 species, 14.5%) was found in the alien flora of the Middle Volga region. For the first time, information is provided on the findings of such species as Cleome spinosa , Echinacea purpurea , Grindelia squarrosa , Jovibarba globifera , Phaseolus vulgaris , and Rudbeckia laciniata . All listed species are accompanied by comments. Among alien plants is dominated by epecophytes (149 species, 32.3%) and ephemerophytes (148 species, 32.1%), 142 species are colonophytes (30.8%) and 22 (4.8%) are agriophytes. 21 species belong to the disappeared ones, they are listed in the general list, but are not included in the analysis. Currently, there is a high rate of adventization of the regional flora – 161 species (35.0% of their total number) recorded in the last 20 years. According to the modes of introduction, alien species are distributed almost equally – 227 xenophytes (49.2%) and 234 ergasiophygophytes (50.8%). The most common alien species in the region have been identified. The results of distribution of alien species are presented by habitat types.
Article
[No formal abstract - Correspondence section of Phytotaxa] The lectotype of Chenopodium acerifolium Andrz. (considered lost until December 2017) designated by Dvořák in 1987 has been rediscovered at KW. Thus, the later lectotype designation (Sukhorukov 2014) is now superseded, as well as the epitype supporting that lectotype (Mosyakin 2017). The rediscovered lectotype (KW001002888) is, however, severely damaged and in its present state of preservation is no longer properly diagnostic of and representative for the species. Because of that the new epitype supporting the rediscovered lectotype is designated (KW001002780, the specimen from the Besser collection at KW collected and annotated by Andrzejowski). PDF is available upon request.
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Four new taxa and nine new combinations are required for forthcoming floristic works by the authors. The new taxa are Centaurium tenuiflorum (Hoffmanns. & Link) Fritsch subsp. anglicum T.C.G.Rich & McVeigh, subsp. nov.; Centaurium × klattii P.Fourn. ex T.C.G.Rich, hyb. nov.; Centaurium × ubsdellii T.C.G.Rich, hyb. nov.; and Gentianella amarella (L.) Börner subsp. occidentalis T.C.G.Rich & McVeigh, subsp. nov. The new combinations are Centaurium erythraea Rafn var. latifolium (Sm.) T.C.G.Rich, comb. et stat. nov.; Gentianella amarella (L.) Börner subsp. anglica (Pugsley) T.C.G.Rich & McVeigh, comb. et stat. nov.; Aria parviloba (T.C.G.Rich) Sennikov & Kurtto, comb. nov.; Cotula sessilis (Ruiz & Pav.) Stace, comb. nov.; Elymus × drucei (Stace) Stace, comb. nov.; Elymus repens (L.) Gould f. aristatus (Schumach.) Stace, comb. nov.; Elymus athericus (Link) Kerguélen f. setigerus (Dumort.) Stace, comb. nov.; Ulmus minor Mill. subsp. cornubiensis (Weston) Stace, comb. et stat. nov.; and Dysphania ambrosioides (L.) Mosyakin & Clemants var. anthelmintica (L.) Stace, comb. nov.
Book
This volume - the first of this series dealing with angiosperms - comprises the treatments of 73 families, representing three major blocks of the dicotyledons: magnoliids, centrosperms, and hamamelids. These blocks are generally recognized as subclasses in modern textbooks and works of reference. We consider them a convenient means for structuring the hundreds of di­ cotyledon families, but are far from taking them at face value for biological, let alone mono­ phyletic entities. Angiosperm taxa above the rank of family are little consolidated, as is easily seen when comparing various modern classifications. Genera and families, in contrast, are comparatively stable units -and they are important in practical terms. The genus is the taxon most frequently recognized as a distinct entity even by the layman, and generic names provide the key to all in­ formation available about plants. The family is, as a rule, homogeneous enough to conve­ niently summarize biological information, yet comprehensive enough to avoid excessive re­ dundance. The emphasis in this series is, therefore, primarily on families and genera.
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Differences between the heterocarpous diaspores of Aellenia autrani (Post) Zoh., as well as their ontogeny, are described. The diaspores differ in their location on the plant, in the size, thickness and structure of the fibres of their winged perianths, in the structure of fibres of the pericarp, in cell wall thickness in the testa, in the ultrastructure of the chloroplasts and consistency and density of aleurone grains of the embryo.