Scorzonera sensu lato (Asteraceae, Cichorieae) – taxonomic reassessment in the light of new molecular phylogenetic and carpological analyses

Scorzonera comprises 180–190 species and belongs to the subtribe Scorzonerinae. Its circumscription has long been the subject of debate and available molecular phylogenetic analyses affirmed the polyphyly of Scorzonera in its wide sense. We provide a re-evaluation of Scorzonera and other related genera, based on carpological (including anatomical) and extended molecular phylogenetic analyses. We present, for the first time, a comprehensive sampling, including Scorzonera in its widest sense and all other genera recognised in the Scorzonerinae. We conducted phylogenetic analyses using Maximum Parsimony, Maximum Likelihood and Bayesian analyses, based on sequences of the nuclear ribosomal ITS and of two plastid markers (partial rbcL and matK) and Maximum Parsimony for reconstructing the carpological character states at ancestral nodes. Achene characters, especially related to pericarp anatomy, such as general topography of the tissue types, disposition of the mechanical tissue and direction of its fibres, presence or absence of air cavities, provide, in certain cases, support for the phylogenetic lineages revealed. Confirming the polyphyly of Scorzonera, we propose a revised classification of the subtribe, accepting the genera Scorzonera (including four major clades: Scorzonera s. str., S. purpurea, S. albicaulis and Podospermum), Gelasia, Lipschitzia gen. nov. (for the Scorzonera divaricata clade), Pseudopodospermum, Pterachaenia (also including Scorzonera codringtonii), Ramaliella gen. nov. (for the S. polyclada clade) and Takhtajaniantha. A key to the revised genera and a characterisation of the genera and major clades are provided

A new endemic species of Sesuvium (Aizoaceae: Sesuvioideae) from the Caribbean Basin, with further notes on the genus composition in the West Indies

A distinctive new species, Sesuvium curassavicum Sukhor. (Aizoaceae: Sesuvioideae), restricted to the Caribbean Basin (Kingdom of the Netherlands: Curacao and Bonaire Islands, North Colombia: La Guajira Department, and North Venezuela: Falcon State), is described and illustrated. It differs from all other perennial species growing in the West Indies by its papillate stems and wrinkled seeds. Based on the molecular phylogenetic analysis of nrDNA (ITS) and three plastid regions (rps16 gene intron, atpB-rbcL and trnL-trnF intergenic spacers), S. curassavicum is included in the 'American' clade, but its relationships are not fully resolved. The samples of the plants known as S. microphyllum fall within the 'Sesuvium portulacastrum' clade, and for that reason this species is considered here as a synonym of S. portulacastrum being an ecological form of the latter species. Sesuvium revolutifolium, S. ortegae and S. revolutum, described from cultivated plants are established as earlier synonyms of S. verrucosum, for which S. revolutifolium has priority and is proposed here as the correct name. These three species names seem to share the same provenance which cannot be Cuba, as stated in the protologue for S. revolutifolium, but rather Mexico. The name Sesuvium sessile is discussed and merged with S. portulacastrum. A new diagnostic key to the Sesuvium species in the West Indies is provided. In total, we accept for the West Indies the following species: S. curassavicum, S. humifusum, S. maritimum, S. portulacastrum and S. rubriflorum. The origins of collections of the neotype of Radiana petiolata and the holotypes of Sesuvium microphyllum and S. spathulatum are clarified.Peer reviewe

Biogeography and Systematics of the Genus <i>Axyris</i> (Amaranthaceae s.l.)

Axyris is a small genus of six species with a disjunct geographic range. Five species are present in Siberia, Central Asia, the Himalayas, and Tibet, whereas Axyris caucasica has been registered in the Central Caucasus only. Axyris species diversity is the highest in the Altai Mountains (four spp.), followed by the Tian Shan and Pamir Mountains (three spp.), and the Himalayas and Tibet (two spp.). Axyris sphaerosperma, sometimes considered endemic to Southern Siberia, in fact has a disjunct range: it is present in the lowlands of Eastern Siberia and in the Altai, Tian Shan, and Pamir Mountains. It has also been found in Mongolia and China for the first time. An updated detailed distribution of Axyris in Siberia is presented on the basis of thorough herbarium revisions. One nuclear and three plastid markers were selected for phylogenetic analysis. Divergence times were estimated using a time-calibrated Bayesian approach. Axyris shows two major clades: an Axyris amaranthoides clade and a clade including the remaining species. The latter clade consists of two subclades (A. sphaerosperma/A. caucasica and A. mira/A. prostrata + A. hybrida). The crown age for Axyris dates back to the Early Pliocene (~5.11 mya, the Zanclean). The ancestral range of Axyris covers Southern Siberia, Mongolia, NW China, and the Tian Shan/Pamir Mountains, with extensions toward Eastern Siberia, the Himalayas/Tibet, and the Caucasus. Fruit and seed characteristics of Axyris are discussed with reference to the present phylogenetic results. Closely related A. sphaerosperma and A. caucasica have the thickest seed coat among all Chenopodiaceae, and these traits have probably evolved as adaptations to extremely low winter temperatures. This reproductive peculiarity may explain the disjunct range of A. sphaerosperma, which is restricted to harsh climatic conditions

Evolutionary relationships, biogeography and morphological characters of Glinus (Molluginaceae), with special emphasis on the genus composition in Sub-Saharan Africa

Glinus is a small genus of Molluginaceae with 8-10 species mostly distributed in the tropics of the World. Its composition and evolutionary relationships were poorly studied. A new molecular phylogeny constructed here using nuclear (ITS) and chloroplast (rbcL, trnK-matK) markers confirmed the monophyly of the as sister to the remainder of the genus followed by G. oppositifolius. Three other clades are: G. hirtus with G. orygioides; G. radiatus and G. lotoides; the latter is represented by asample from North America, and G. zambesiacus as sister to G. setiflorus + G. lotoides + G. dictamnoides.On the plastid gene tree, G. bainesii + G. oppositifolius form a sister clade to all other Glinus species. The next clade is formed by G. hirtus and G. orygioides followed by G. radiatus plus an American sample of G. lotoides. The next branch comprises G. setiflorus as sister to G. zambesiacus + G. lotoides + G. dictamnoides. Glinus seems to have originated from Africa around the Late Eocene or Early Miocene, with further radiations to Australia and the Americas during the Late Miocene or Late Pliocene. Compared with the previous limited character set used for the diagnostics, we have found ten new morphological and carpological traits distinguishing Glinus members. In both trees based on nuclear and plastid datasets, the major phylogenetic clades cannot be characterized by the peculiar morphological characters. Many shared character states leading to their contrasting pattern in the multivariate analysis model are interpreted as a high homoplasy in the phylogenetically distant species. We paid special attention to the composition of the genus in Sub-Saharan Africa, a region with the greatest species diversity. Our results provide new insight into the taxonomy of Glinus in this region. Glinus lotoides var. virens accepted in many previous works is a synonym of G. dictamnoides that is closely related to G. lotoides based on molecular analysis and morphological characters. The status of the American populations of G. lotoides needs further investigation due to different characters of the specimens from the Old and the New World. Many specimens previously identified as G. lotoides var. virens and as the intermediates G. lotoides x G. oppositifolius belong to G. zambesiacus sp. nov. and G. hirtus comb. nov. (= Mollugo hirta); the latter species is resurrected from synonymy after 200 years of unacceptance. In some African treatments, G. hirtus was known under the invalidly published name G. dahomensis. Glinus zambesiacus is distributed in the southern and eastern parts of tropical Africa, and G. hirtus previously assumed to be endemic to West Africa is indeed a species with a wide distribution across the tropical part of the continent. Glinus microphyllus previously accepted as endemic to West Tropical Africa together with other new synonyms (G. oppositifolius var. lanatus, G. herniarioides, Wycliffea rotundifolia) is considered here as G. oppositifolius var. keenanii comb. nov. (= Mollugo hirta var. keenanii), a variety found across the entire distribution of G. oppositifolius (Australia, Asia, and Africa). The presence of the American G. radiatus in Africa is not confirmed, and all records of this species belong to G. hirtus. M. setiflora, Pharnaceum pentagynum, Wycliffea) as well as a neotype of G. trianthemoides are designated. A new key to the identification of all Glinus species in Sub-Saharan Africa is provided. A checklist is given of all accepted species in this region (G. bainesii, G. hirtus, G. lotoides, G. oppositifolius s.l., G. setiflorus, and G. zambesiacus) with their nomenclature, morphological description and geographical distribution.Peer reviewe

Seed characters in Molluginaceae (Caryophyllales): implications for taxonomy and evolution

Molluginaceae include c. 90 species distributed worldwide. The circumscription and intrafamilial relationships were recently re-evaluated after molecular investigations, but the seed characters and their evolutionary trends are poorly known. Seeds of 76 species from all 11 genera of Molluginaceae were studied. Fourteen morphological and anatomical seed characters were analysed, with further conclusions for characterization of the genera or major clades in the family. Pharnaceum in its recent circumscription is carpologically heterogeneous, and all seed characters of P. namaquense and P. pusillum, which were transferred into this genus based on the morphological similarities, indicate their placement in Hypertelis. The generic placement of P. serpyllifolium is also ambiguous. The evolutionary history of all 14 characters under consideration was reconstructed using phylogenetic analysis, and the ancestral seed characters of Molluginaceae are described. The Polpoda - Adenogramma + Psammotropha subclade is the only lineage in which the one-seeded fruits evolved. The loss of the stalactites in the outer walls of the testa cells seems to be connected with the reduction in the testa thickness. Kewa (Kewaceae, previously included in Hypertelis) shares many carpological homoplasies with Molluginaceae. The seed traits in the 'globular inclusion' clade (core Caryophyllales) are briefly discussed, and Molluginaceae are compared with other representatives of the clade. Among the taxa of the 'globular inclusion' clade with multi-seeded fruits, the smallest seeds have evolved in some genera of Molluginaceae and Aizoaceae