Previous Infrageneric Classifications Research Articles

A tough nutlet to crack: Resolving the phylogeny of Thesium (Thesiaceae), the largest genus in Santalales

AbstractWith over 350 species, Thesium is the largest genus in Santalales. It is found on all continents except Antarctica; however, its highest diversity is in the Cape Floristic Region of South Africa where approximately half the species occur. Thesium samples of ca. 590 collections from throughout its entire geographic range were obtained and nuclear ribosomal ITS sequenced from 396 accessions representing 196 named taxa and 30 currently unnamed taxa for a total of ca. 230 species. In addition, two chloroplast genome spacers (trnDT, trnLF) were sequenced from 269 and 315 accessions, respectively. Maximum parsimony, maximum likelihood and Bayesian methods were employed to generate gene trees and infer phylogenies. The value of the morphological characters traditionally used in the taxonomy of the genus and previous infrageneric classifications are discussed. Broad scale relationships were generally congruent among the ITS and the chloroplast trees. For example, both the nuclear and chloroplast trees support the presence of Eurasian and African clades. In contrast, major incongruence was detected between nuclear and chloroplast trees for a number of taxa including the recently described T. nautimontanum that is sister to the entire African clade on the ITS tree. Although the causes of this incongruence are currently unknown, a novel form of chloroplast capture is hypothesized. A hypothesis of the biogeographical history of the genus based on our molecular phylogeny is presented.

A revised delimitation of the species‐rich genus Pilea (Urticaceae) supports the resurrection of Achudemia and a new infrageneric classification

AbstractEnsuring that genera are monophyletic should result in a stable classification that better reflects evolutionary history, and which can serve as a framework for answering broader scientific questions. It is also important that species can be assigned to genera easily and unambiguously so as to remove barriers to identification and species discovery. Pilea, with 933 published names and likely more than 700 spp. is the largest genus within the Urticaceae and was last monographed in 1869. Whilst the monophyly of the genus has been proposed by previous authors, this has been based on incomplete taxon sampling that has failed to resolve the position of key taxa. We aimed to generate a robust phylogeny for Pilea and allied genera that could test the monophyly of the genus and provide a framework for a taxonomic revision of this species‐rich yet poorly studied genus. To do so, we sought to sample taxa encompassing previous infrageneric classifications and species with anomalous inflorescences or flower morphology and to use the resulting phylogeny to evaluate the delimitation of Pilea and to establish an infrageneric classification. In addition, we included a representative of the Polynesian genus Haroldiella, which, morphologically, seemed indistinguishable from Pilea. Using two plastid and one nuclear region, we constructed phylogenies using Bayesian inference, maximum likelihood and maximum parsimony approaches. We used our BI phylogeny to evaluate the informativeness of 22 morphological characters and used both to delimit monophyletic groups and infrageneric sections. Our results recovered Pilea as paraphyletic, a consequence of the recovery of a monophyletic clade comprising Lecanthus and Pilea sect. Achudemia and sect. Smithiella, neither of which had been adequately sampled in previous studies. We also recovered Pilea as paraphyletic with respect to Haroldiella. Pilea (including Haroldiella) was recovered as sister to the clade comprising Lecanthus and Pilea sect. Achudemia and sect. Smithiella. We identified isomery between male and female flowers, flower part number, male sepal arrangement and achene ornamentation as being phylogenetically informative characters that can be used to distinguish Achudemia (Pilea sect. Achudemia and sect. Smithiella) from Pilea. We also identified a trend of decreasing merism and fruit size, correlated with an increase in species‐richness across the phylogeny which our results suggest may indicate a shift in pollen and fruit dispersal, pollen dispersal becoming more kinetic and fruit dispersal less reliant on animals. On the basis of our evaluation of both morphological characters and phylogenetic relationships we propose a new infrageneric classification for the genus comprising eight sections, five of which we propose for the first time here: Pilea sect. Angulatae, sect. Plataniflorae, sect. Tetraphyllae, sect. Trimeris and sect. Verrucosae.

Advances in the phylogeny of the South American cool-season grass genus Chascolytrum (Poaceae, Pooideae): a new infrageneric classification

Abstract Chascolytrum, as currently circumscribed, includes 22–23 South American species that were previously included in nine different genera (Chascolytrum, Briza, Poidium, Calotheca, Microbriza, Gymnachne, Rhombolytrum, Lombardochloa and Erianthecium). Due to the remarkable morphological diversity, the relationships in Chascolytrum s.l. have remained poorly understood, and no infrageneric classification could be proposed based on the latest molecular phylogenetic studies. In this study, we combined molecular (GBSSI, trnL-trnL-trnF and rps16 intron) and morphological characters to investigate the phylogenetic relationships in Chascolytrum s.l. Based on this, morphologically diagnosable clades were recognized as eight sections (Calotheca, Chascolytrum, Hildaea, Lombardochloa, Microbriza, Obovatae, Poidium and Tricholemma), of which three are new and three are monospecific. We describe each section and discuss the new infrageneric classification in comparison with the previous infrageneric classification proposed for the group under the genus Briza. A taxonomic key and images for most of the species in each section are provided. Last, the use of single-copy nuclear genes and morphological data for future phylogenetic reconstructions encompassing Chascolytrum is highlighted.

Phylogeny of Paullinia L. (Paullinieae: Sapindaceae), a diverse genus of lianas with dynamic fruit evolution

Paullinia L. is a genus of c. 220 mostly Neotropical forest-dwelling lianas that display a wide diversity of fruit morphologies. Paullinia resembles other members of the Paullinieae tribe in being a climber with stipulate compound leaves and paired inflorescence tendrils. However, it is distinct in having capsular fruits with woody, coriaceous, or crustaceous pericarps. While consistent in this basic plan, the pericarps of Paullinia fruits are otherwise highly variable—in some species they are winged, whereas in others they are without wings or covered with spines. With the exception of the water-dispersed indehiscent spiny fruits of some members of Paullinia sect. Castanella, all species are dehiscent, opening their capsules while they are still attached to the branch, to reveal arillate animal-dispersed seeds. Here we present a molecular phylogeny of Paullinia derived from 11 molecular markers, including nine newly-developed single-copy nuclear markers amplified by microfluidics PCR. This is the first broadly sampled molecular phylogeny for the genus. Paullinia is supported as monophyletic and is sister to Cardiospermum L., which together are sister to Serjania Mill + Urvillea Kunth. We apply this novel phylogenetic hypothesis to test previous infrageneric classifications and to infer that unwinged fruits represent the ancestral condition, from which there were repeated evolutionary transitions and reversals. However, because the seeds of both winged and unwinged fruits are dispersed by animals, we conclude that the repeated transitions in fruit morphology may relate to visual display strategies to attract animal dispersers, and do not represent transitions to wind dispersal.

Sansevieria (Asparagaceae, Nolinoideae) is a herbaceous clade within Dracaena: inference from non-coding plastid and nuclear DNA sequence data

The evolutionary history of the dracaenoid genera Dracaena and Sansevieria (Asparagaceae, Nolinoideae) remains poorly resolved, despite long-recognised issues with their generic boundaries and increased attention paid by both horticulturalists and taxonomists. In this study we aim to: (1) elucidate evolutionary relationships within and between Dracaena and Sansevieria using molecular phylogenetic inference of both nuclear (nDNA) and plastid (cpDNA) markers, (2) examine the infrageneric classifications of each genus, and (3) revise the circumscription of the dracaenoids in light of morphological and phylogenetic evidence. In total, we sampled 21 accessions of Dracaena (ca. 19 species), 27 accessions of Sansevieria (ca. 26 species), and six outgroup taxa. Phylogenetic analyses were based on nucleotide sequences of two non-coding plastid DNA regions, the trnL-F region (trnL intron and trnL-trnF intergenic spacer) and rps16 intron, and the low-copy nuclear region At103. Phylogenetic hypotheses were constructed using maximum parsimony, maximum likelihood, and Bayesian inference. Individual datasets were analysed separately and, after testing for congruence, as combined datasets. We recovered instances of soft incongruence between nDNA and cpDNA datasets in Sansevieria, but general trends in the dracaenoids were congruent, although often poorly supported or resolved. The dracaenoids constitute a strongly supported monophyletic group. Dracaena was resolved as a paraphyletic grade embedded with two clades of Sansevieria, a primary clade comprising most species, and a secondary clade including S. sambiranensis, a distinctive species from Madagascar. The backbone of our phylogeny was only resolved in nDNA analyses, but combined analyses recovered strongly supported species groups. None of the previous infrageneric classifications were supported by our phylogeny, and biogeographic groupings were frequently more significant than morphology. More work is needed to resolve internal relationships in the dracaenoids, but we support a recent proposal to recognise a broadened circumscription of Dracaena that includes Sansevieria. We provide a generic description for the recircumscribed Dracaena and new combinations for several species of Sansevieria in Dracaena.

A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia

Trigonostemon is taxonomically revised for Malesia based on herbarium collections and field observations. Thirty-eight species are recognized in Malesia, of which four of uncertain status and four newly described. The previous infrageneric classifications are briefly reviewed, but none is accepted. Some useful characters are discussed. An identification key, nomenclature, descriptions, typification, geographic distributions and taxonomic notes are provided.

A New Infrageneric Classification of <I>Mucuna</I> (Leguminosae-Papilionoideae): Supported by Morphology, Molecular Phylogeny and Biogeography

Abstract The previous infrageneric classification of Mucuna (Leguminosae, Papilionoideae) recognized two subgenera, M. subg. Mucuna and M. subg. Stizolobium, but that classification is not supported fully by molecular phylogenetic analyses, which reveal three main clades in Mucuna (rather than the traditional two). A new taxon M. subg. Macrocarpa is proposed based on the results of a molecular phylogenetic analysis, supported by fruit characters and biogeography. Historically, the representatives of this new subgenus were considered as members of M. subg. Mucuna, but species of subgenus Macrocarpa differ from species of the other two subgenera by their longer ovaries containing a higher number of ovules and, consequently, longer pods containing more seeds, and by the different fruit length to width ratio. This study presents a new infrageneric classification of the genus Mucuna. The six species of M. subg. Macrocarpa are reviewed, and species descriptions, typifications (including five new lectotypes), a ...

Molecular and morphological data supporting phylogenetic reconstruction of the genus Goniothalamus (Annonaceae), including a reassessment of previous infrageneric classifications.

Data is presented in support of a phylogenetic reconstruction of the species-rich early-divergent angiosperm genus Goniothalamus (Annonaceae) (Tang et al., Mol. Phylogenetic Evol., 2015) [1], inferred using chloroplast DNA (cpDNA) sequences. The data includes a list of primers for amplification and sequencing for nine cpDNA regions: atpB-rbcL, matK, ndhF, psbA-trnH, psbM-trnD, rbcL, trnL-F, trnS-G, and ycf1, the voucher information and molecular data (GenBank accession numbers) of 67 ingroup Goniothalamus accessions and 14 outgroup accessions selected from across the tribe Annoneae, and aligned data matrices for each gene region. We also present our Bayesian phylogenetic reconstructions for Goniothalamus, with information on previous infrageneric classifications superimposed to enable an evaluation of monophyly, together with a taxon-character data matrix (with 15 morphological characters scored for 66 Goniothalamus species and seven other species from the tribe Annoneae that are shown to be phylogenetically correlated).

Evolution of Asparagus L. (Asparagaceae): Out-of-South-Africa and multiple origins of sexual dimorphism

In the most comprehensive study to date we explored the phylogeny and evolution of the genus Asparagus, with emphasis on the southern African species. We included 211 accessions, representing 77 (92%) of the southern African, 6 (17%) of the tropical African, 10 (56%) of the strictly European and 6 (9%) of the Eurasian species. We analyzed DNA sequences from three plastid regions (trnH-psbA, trnD-T, ndhF) and from the nuclear region phytochrome C (PHYC) with parsimony and maximum likelihood methods, and recovered a monophyletic Asparagus. The phylogeny conflicts with all previous infra-generic classifications. It has many strongly supported clades, corroborated by morphological characters, which may provide a basis for a revised taxonomy. Additionally, the phylogeny indicates that many of the current species delimitations are problematic. Using biogeographic analyses that account for phylogenetic uncertainty (S-DIVA) and take into account relative branch lengths (Lagrange) we confirm the origin of Asparagus in southern Africa, and find no evidence that the dispersal of Asparagus follow the Rand flora pattern. We find that all truly dioecious species of Asparagus share a common origin, but that sexual dimorphism has arisen independently several times.

History of infrageneric classification, typification of supraspecific names and outstanding transfers in Curcuma (Zingiberaceae)

AbstractIn this paper we provide a thorough overview of past attempts at infrageneric classification of the genus Curcuma (Zingiberaceae). As the recent results of phylogenetic analysis of the genus confirmed that previous infrageneric classifications are not tenable, we provide a revised circumscription of Curcuma with an outline of new infrageneric classification into three subgenera, C. subg. Curcuma, C. subg. Ecomatae and C. subg. Hitcheniopsis including lists of species to be included in each subgenus. Three previously recognized genera, Laosanthus, Smithatris and Stahlianthus, are sunk to Curcuma and two species previously recognized in the genus Hitchenia, H. caulina and H. glauca, are transferred/re–recognized to Curcuma. The previously proposed transfers of the monospecific genus Paracautleya, Hedychium scaposum (Kaempferia scaposa, Monolophus scaposus) and Kaempferia candida, to Curcuma are also confirmed. All connected nomenclatural innovations, corrections and outstanding typifications, inclusive those of infrageneric names, are effected in this paper. A list of excluded names originally described as members of Curcuma, but now accepted as members of other genera is also included.

Phenetic differentiation and use-type delimitation in Amaranthus spp. from worldwide origins

Amaranthus species have been rediscovered as promising food crops mainly due to their resistance to heat, drought, diseases and pests, and the high nutritional value of both seeds and leaves. This genus include the grain crops Amaranthus cruentus, Amaranthus hypochondriacus and to a less extent Amaranthus caudatus and also the weedy and vegetable species Amaranthus blitum, Amaranthus dubius, Amaranthus graecizans, Amaranthus spinosus, Amaranthus tricolor and Amaranthus viridis. Taxonomic bottlenecks related to similarities between grain, vegetable and weed types are yet to be solved to better understand the evolutionary trend in the group and to develop adequate selection of lines. In the present study, we carried out a phenetic analysis of 100 accessions belonging to nine species with various geographical origins to assess morphological markers and clarify inter- and intraspecific variations among and within species. Among the 30 descriptors used, the most distinguishing characters were related to inflorescence types, floral parts and seed traits. Hierarchical cluster analysis showed a clear demarcation between grain amaranths and other species. Close relationships were found between A. viridis, A. dubius and A. spinosus on the one hand and A. blitum, A. graecizans and A. tricolor on the other. Small-types cultivars of A. dubius were found to be closer to A. spinosus than giant-types. Species grouping were independent of accession origin which gives insight into the robustness of morphological markers. These results provided phylogenetic relationships which are inconsistent with previous infrageneric classification of amaranths and call for further investigations with a larger set of species to clarify relationships among these species and unlock their potential for crop improvement.

Spanish

Species of Paspalum group Gardneriana are revised as a whole for the first time. Seven species are treated in this work, being the group characterized by including annual or perennial species, with spikelets usually obovoid, upper glume absent or reduced, and upper anthecium indurate and strongly papillose, with verrucose papillae all over its surface. A key to the species is provided, together with a discussion of previous infrageneric classifications and relationships of Gardneriana; morphological descriptions, and illustrations of all species are also presented. The following species are included in Paspalum group Gardneriana: Paspalum burchellii, P. delicatum, P. gardnerianum, P. nudatum, P. pictum, P. reduncum, and P. subsesquiglume. Also, lectotypes are designated for P. burchellii, P. connectens, P. reduncum, and P. subsesquiglume; P. gemmosum is defined as a new synonym of P. subsesquiglume.

First molecular phylogeny of the pantropical genus Dalbergia: implications for infrageneric circumscription and biogeography

The genus Dalbergia with c. 250 species has a pantropical distribution. In spite of the high economic and ecological value of the genus, it has not yet been the focus of a species level phylogenetic study. We utilized ITS nuclear sequence data and included 64 Dalbergia species representative of its entire geographic range to provide a first phylogenetic framework of the genus to evaluate previous infrageneric classifications based on morphological data. The phylogenetic analyses performed suggest that Dalbergia is monophyletic and that it probably originated in the New World. Several clades corresponding to sections of these previous classifications are revealed. Taking into account that there is not a complete correlation between geography and phylogeny, and the estimation that the Dalbergia stem and crown clades are 40.4–43.3 mya and 3.8–12.7 mya, respectively, it is plausible that several long distance dispersal events underlie the pantropical distribution of the genus.

Phylogeny of palaeotropic Derris‐like taxa (Fabaceae) based on chloroplast and nuclear DNA sequences shows reorganization of (infra)generic classifications is needed

Palaeotropic Derris-like taxa (family Fabaceae, tribe Millettieae) comprise 6-9 genera. They are well known as important sources of rotenone toxin, which are used as organic insecticide and fish poison. However, their phylogenetic relationships and classification are still problematic due to insufficient sampling and high morphological variability. Fifty species of palaeotropic Derris-like taxa were sampled, which is more than in former studies. Three chloroplast genes (trnK-matK, trnL-F IGS, and psbA-trnH IGS) and nuclear ribosomal ITS /5.8S were analyzed using parsimony and Bayesian methods. Parsimony and Bayesian analyses of individual and combined markers show more or less similar tree topologies (only varying in terminal branches). The old-world monophyletic genera Aganope, Brachypterum, and Leptoderris are distinct from Derris s.s., and their generic status is here confirmed. Aganope may be classified into two or three subgeneric taxa. Paraderris has to be included in Derris s.s. to form a monophyletic group. The genera Philenoptera, Deguelia, and Lonchocarpus are monophyletic and distinct from each other and clearly separate from Derris s.s. Morphologically highly similar species of Derris s.s. are shown to be unrelated. Our study shows that previous infrageneric classifications of Derris are incorrect. Paraderris elliptica may contain several cryptic lineages that need further investigation. The concept of the genus Derris s.s. should be reorganized with a new generic circumscription by including Paraderris but excluding Brachypterum. Synapomorphic morphological features will be examined in future studies, and the status of the newly defined Derris and its closely related taxa will be formalized.

Phylogeny of Curcuma (Zingiberaceae) based on plastid and nuclear sequences: Proposal of the new subgenus Ecomata

AbstractCurcuma comprises 120 species that occur throughout tropical and subtropical Asia. The taxonomy of the genus is haunted by polyploid speciation and homoploid hybridization, making it the most challenging genus in Zingibereae (Zingiberaceae). Curcuma is best known for turmeric (C. longa), but numerous species are extensively used as medicinal plants, ornamentals, and sources of starch, among many other uses. The delimitation of the genus has been a matter of dispute since its establishment by Linnaeus (1753), and further conflict has arisen from recent molecular and morphological studies suggesting either paraphyly of Curcuma or the necessity to broaden the genus to include four small genera (Laosanthus, Paracautleya, Stahlianthus, Smithatris) as well as several species currently placed in Kaempferia and Hitchenia. All previous infrageneric classifications were based on limited material that did not include species from the Indochinese f loristic region, and these classifications are unable to unequivocally accommodate all currently known members of the genus. To test the monophyly and delimitation of Curcuma and to gain more insight into infrageneric relationships, three plastid regions (trnL–trnF, psbA–trnH, matK) and the internal transcribed spacer (ITS) of nuclear ribosomal DNA were sequenced. Fifty Curcuma species covering the morphological and geographic variation of the genus and 12 Curcuma–like species currently or previously treated as members of other genera were included in this study. In addition, four Zingibereae and three other Zingiberaceae species were used as outgroups. The results of maximum parsimony and Bayesian analyses clearly support a broad generic boundary for Curcuma, with inclusion of Laosanthus, Paracautleya, Stahlianthus, Smithatris and some species of Kaempferia and Hitchenia (K. scaposa, K. candida, H. caulina, H. glauca). Four main groups in Curcuma s.l. were detected, and their importance for classification at the subgenus level is discussed. A new infrageneric classification is proposed here with a formal description of a new subgenus. Cloning uncovered a broad range of variation of ITS sequences within individuals, particularly in the terminal ‘Curcuma’ group containing representatives of the nominal subgenus Curcuma. This ‘intra–individual ITS polymorphism’ increases with ploidy level and is coupled with preferred vegetative reproduction. Additional studies are needed to further uncover highly complex relationships in this subgenus.

MICROFITOLITOS DE LAS POACEAE ARGENTINAS: II. MICROFITOLITOS FOLIARES DE ALGUNAS ESPECIES DEL GENERO PANICUM (POACEAE, PANICEAE) DE LA PROVINCIA DE ENTRE RÍOS

Foliar phytolith morphology of 8 species the Panicum ( P. bergii Arechav., P. decipiens Nees. ex Trin., P. dichotomiflorum Michx., P. gouinii Fourn., P. hians Elliott, P. laxum Sw., P. prionitis Nees and P. sabulorum Lam.) present in the prairie of Entre Rios Province, was described. Cluster analysis (UPGMA) and ordination by principal component analysis (PCA) were performed on 49 morphological characters from the 8 phytolith assemblages (OTUs). The results defined four groups: the first group includes P. laxum assemblage, the second one P. hians and P. decipiens assemblages, the third grollp P. prionitis assemblage and the last one with P. dichotomiflorum + [P. sabulorum + (P. bergii +P. gouinii)] assemblages. The 8 phytolith assemblages showed Panicoideae affinity ( sensu Twiss, 1992), and differed from the typical phytolith assemblages of other subfamilies. This study supported the previous infrageneric classification proposed by Zuloaga et al. (1993), with the exception of subgenus Dichanthelium wich appeared in this analysis related to species of subgenus Panicum .

Phylogenetic Analyses of Clematis (Ranunculaceae) based on Sequences of Nuclear Ribosomal ITS and Three Plastid Regions

Abstract Clematis, a largely temperate genus of vines and lianas, consists of approximately 300 species. Based on a sampling of about 75 species, sequences of the nrITS, the plastid atpB—rbcL spacer, psbA—trnH—trnQ spacer, and rpoB—trnC spacer regions were analyzed using parsimony, maximum likelihood, and Bayesian inference methods. Analyses of the combined data set by the three methods yielded similar topologies. Previously recognized genera including Archiclematis and Naravelia are nested within Clematis, supporting the merging of these genera within Clematis. Ten major clades with various levels of support were detected in the combined analyses. Our results in general do not support previous infrageneric classifications based on morphological characters and suggest significant convergence in floral and vegetative characters in Clematis. Several clades were resolved as regional geographic groups. Bayesian dating suggests a relatively ancient origin of the genus in the Oligocene, yet a relatively recent ...

Molecular Phylogenetics of <I>Galeandra</I> (Orchidaceae: Catasetinae) based on Plastid and Nuclear DNA Sequences

Galeandra is a neotropical genus with its center of diversity in the Amazon region. It comprises approximately 18 species of epiphytic and terrestrial herbs that are easily recognizable by their funnel-shaped labellum. We examined the phylogenetic relationships among species of Galeandra inferred from nucleotide sequences from three plastid (psbA-trnH, rpoB-trnC, and trnS-trnG) and two nuclear (ITS and ETS) DNA regions. The five data matrices were analyzed individually and in combined analyses using parsimony and maximum likelihood. We found that the epiphytic species G. devoniana is sister to the remainder of the genus, and that the other species form two groups, one consisting of epiphytic species and the other composed of terrestrial species. Adaptation to the terrestrial environment from a probable epiphytic ancestor was of great importance in the evolution of Galeandra. The relationships found in this study do not support previous infrageneric classifications.

Molecular phylogeny and systematics of the banana family (Musaceae) inferred from multiple nuclear and chloroplast DNA fragments, with a special reference to the genus Musa

Musaceae is a small paleotropical family. Three genera have been recognised within this family although the generic delimitations remain controversial. Most species of the family (around 65 species) have been placed under the genus Musa and its infrageneric classification has long been disputed. In this study, we obtained nuclear ribosomal ITS and chloroplast (atpB-rbcL, rps16, and trnL-F) DNA sequences of 36 species (42 accessions of ingroups representing three genera) together with 10 accessions of ingroups retrieved from GenBank database and 4 accessions of outgroups, to construct the phylogeny of the family, with a special reference to the infrageneric classification of the genus Musa. Our phylogenetic analyses elaborated previous results in supporting the monophyly of the family and suggested that Musella and Ensete may be congeneric or at least closely related, but refuted the previous infrageneric classification of Musa. None of the five sections of Musa previously defined based on morphology was recovered as monophyletic group in the molecular phylogeny. Two infrageneric clades were identified, which corresponded well to the basic chromosome numbers of x=11 and 10/9/7, respectively: the former clade comprises species from the sections Musa and Rhodochlamys while the latter contains sections of Callimusa, Australimusa, and Ingentimusa.

Usefulness of morphological characters for infrageneric classification of Elatostema (Urticaceae)

In 1896, Hans Hallier was the first author to reduce the two genera Pellionia and Procris to subgeneric status within the genus Elatostema (Urticaceae). In 1935 and 1936, Hilde Schroter and Hubert Winkler proposed the following four subgenera: subg. Elatostema, subg. Elatostematoides, subg. Pellionia and subg. Weddellia, while maintaining Procris as a distinct genus. More recently, Wang (1980a) rejected Schroter and Winkler’s subgeneric classification of Elatostema and proposed a sectional and serial infrageneric classification of recognising as sections Androsyce, Elatostema, Laevisperma, Pellionioides and Weddellia (as ‘Weddelia’). He maintained both Pellionia and Procris as distinct genera. All previous researchers of Elatostema and related taxa primarily based their classifications on the morphology of leaves, stipules, inflorescence and receptacle. Our analysis, based on similar morphological characters, does not support the previous infrageneric classifications. Procris forms a monophyletic clade, nested within a clade consisting of several species of Elatostema subg. Pellionia and one of subg. Elatostematoides. Elatostema auriculatifolium (subgeneric classification unclear) is also included within this clade. This clade is sister to the E. latifolium–E. tsoongii pair of species (also subg. Pellionia), subg. Elatostema (the remaining species of this subgenus), species of subg. Weddellia and E. rostratum (subg. Elatostematoides). Elatostema subg. Weddellia is paraphyletic within subg. Elatostema. The recognition of Elatostematoides, Pellionia and Procris as distinct genera is not supported.