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A taxonomic revision of the endemic Malagasy genus Helmiopsis H. Perrier (Malvaceae s.l.) is presented, based on material that has been collected since the last complete revision by Arènes. Nine species and one subspecies are recognized, of which one species (H. polyandra Appleq.) and one subspecies (H. hily Arènes subsp. boinensis Appleq.) are newly described from Madagascar. Arènes' infrageneric taxonomy is simplified; two sections (section Glandulipetalae Arènes and section Helmiopsis) are recognized. The section Glandulipetalae is typified by H. pseudopopulus (Baill.) Capuron ex Arènes, and H. inversa H. Perrier, the type species for the genus, is lectotypified. Dombeya rigida Baill. is excluded from Helmiopsis. Preliminary conservation assessments using IUCN criteria indicate that most taxa are of potential conservation concern: four species native to the extreme north should be considered Vulnerable, and one species and one subspecies are considered Data Deficient but likely to be at risk.
A revision of the Neotropical genus Bonyunia M. R. Schomb. ex Progel (Loganiaceae, Antonieae) is provided, including a key to species, description, distribution, IUCN Red List status, and discussion. Bonyunia is morphologically and ecologically diverse with taxonomically informative characters that include habit, seed and leaf morphology, and the shape and indument of the calyx, bracts, and bracteoles. Bonyunia occurs in lowland regions of the Amazon River watershed (Brazil and Bolivia), the Orinoco River watershed (Colombia and Venezuela), tepuis of the Guayana region and outliers (Brazil, Guyana, Venezuela, and Colombia), and lowland regions of Amazon Basin–facing Andes in Peru, throughout on white sands. Ten species are recognized, including four established species: B. antoniifolia Progel, B. aquatica Ducke, B. minor N. E. Br. (including B. cinchonoides Gleason & Standl.), and B. superba M. R. Schomb. ex Progel. Six species are newly described: B. excelsa J. R. Grant (Colombia), B. magnifica J. R. Grant (Brazil), B. nobilis J. R. Grant (Colombia), B. pulchra Ricketson, J. R. Grant & Liesner (Peru), B. spectabilis J. R. Grant (Guyana), and B. venusta J. R. Grant (Brazil).
Due in part to its distinctive and variable morphology, traditional taxonomy has not resolved the systematic position of Aethionema trinervium Boiss., which has been previously placed in several different genera including Aethionema R. Br., Eunomia DC., Hutchinsia R. Br., and Thlaspi L. Using sequence data from the ITS-1 and ITS-2 regions of ribosomal DNA, A. trinervium has been added to a previously published data set composed of proposed congeners and related taxa in order to clarify its phylogenetic relationships. Our molecular analysis indicates that A. trinervium is not a member of Aethionema, but is instead highly nested within Vania F. K. Mey., a segregate lineage of the nonmonophyletic Thlaspi s.l. Based on these results and subsequent taxonomic recommendations, we transfer A. trinervium to Vania, described from Iran, as the new combination V. trinervia (DC.) Khosravi, Jacquemoud, Menke, Mumm. & Mohsenz. Furthermore, we have lectotypified the species.
The Paleotropical genus Gaertnera Lam. (nom. cons.) comprises 69 species, plus one presumed natural hybrid, of shrubs and small trees found from West Africa to Sulawesi in southeastern Asia, with 13 of them newly described here. Gaertnera is characterized in the Rubiaceae by its tubular stipules of various forms, secondarily superior ovaries, and drupaceous fruits. Molecular phylogenetic analyses support Gaertnera as monophyletic and sister to the Neotropical genus Pagamea Aubl., but do not support infrageneric classification of Gaertnera. The morphology of Gaertnera is notably variable; molecular analyses indicate that most diversification is within regions, and that much of it is autapomorphic or homoplasious. Gaertnera species of Africa, Madagascar, the Mascarene Islands, and Sri Lanka are hermaphroditic and usually demonstrably distylous, while those of Southeast Asia for which information is available are dioecious, sometimes cryptically so, and apparently derived within the genus. All species recognized here are regional endemics, and accordingly regional keys are included here. In Africa, 12 species and two subspecies are recognized in this present work; G. paniculata Benth. is the most widespread of these; G. aurea Malcomber, G. gabonensis Malcomber, and G. letouzeyi Malcomber are newly described here; and the new combination G. longivaginalis (Schweinf. ex Hiern) E. M. A. Petit var. bracteata (E. M. A. Petit) Malcomber is made based on G. bracteata E. M. A. Petit. In Sri Lanka, six species plus the presumed natural hybrid G. ×gardneri Thwaites are recognized; all of these have been previously described; G. vaginans (DC.) Merr. is the most commonly collected. In Southeast Asia, 14 species are recognized here; G. junghuhniana Miq. is the most commonly collected and widespread; G. alstonii Malcomber, G. aphanodioica Malcomber, G. belumutensis Malcomber, G. capitulata Malcomber, and G. kochummenii Malcomber are newly described here. Gaertnera has its center of diversity in Madagascar and the Mascarene Islands, with 36 species and two subspecies recognized in this present work; G. obovata Baker of Madagascar is the most widespread and common; G. ianthina Malcomber, G. lowryi Malcomber, G. monstruosa Malcomber, G. raphaelii Malcomber, and G. schatzii Malcomber are newly described here; and the new combination G. obovata var. sphaerocarpa (Baker) Malcomber is made based on G. sphaerocarpa Baker. Here, G. vaginans is treated as a morphologically well-defined species of Sri Lanka, and the remaining plants included in this species by some previous authors are treated here in 10 additional species, four of them newly described. The following names are newly lectotypified: G. crinita Drake, G. dinklagei
Nyssa yunnanensis W. Q. Yin ex H. N. Qin & Phengklai (Nyssaceae) is a critically endangered range-restricted tree species known from only three small populations in a tropical forest area of southern Yunnan Province, southwestern China. Two types of individuals occur, one bearing staminate flowers and the other with morphologically perfect flowers that produce both pollen and fruit, suggesting an androdioecious breeding system. Field and laboratory studies conducted between 2004 and 2007 indicate, however, that N. yunnanensis is functionally dioecious: pollen from the morphologically perfect flowers is inaperturate and inviable, rendering the trees that bear these flowers functionally female. Field observations showed that the staminate flowers opened 10 to 15 days earlier than the protogynous female flowers but that flowering ceased at nearly the same time in both sexes. Thirty-six species of insects were observed and collected visiting the flowers of N. yunnanensis, four of which served as effective pollinators. Breeding system experiments demonstrated that the predominantly entomophilous pollination system is supplemented by anemophily and further indicated that N. yunnanensis is xenogamous and does not appear to exhibit parthenogenesis. The average sex ratio of individuals within the three populations was female-biased (0.57∶1), but the ratio among flowers was male-biased (2.56∶1) because flower production was higher in males. The 37 known trees of N. yunnanensis are likely the remnants of a once more widespread, abundant species that has been heavily impacted by human disturbance, a fate shared with many other threatened Southeast Asian taxa whose continued survival will require dedicated conservation efforts informed by a detailed understanding of population structure and reproductive biology.
The Hypochaeris sessiliflora complex (Asteraceae, Cichorieae) consists of nine species of the genus from South America (all in section Achyrophorus Scop.) that have sessile or nearly sessile flowering heads surrounded by a rosette of leaves. They occur at 1430–5100 m in elevation along the Andean chain from Venezuela to Chile and Argentina. Two species, H. sessiliflora Kunth and H. meyeniana (Walp.) Benth. & Hook. f. ex Griseb., are extremely polymorphic, and they vary conspicuously in the shape of the external phyllaries and presence or absence of different types of trichomes. They have the widest distributions (Venezuela to central Peru, and Peru to northern Chile and northwestern Argentina, respectively), they flower throughout the year, and they also are primarily associated with dry and sunny habitats. Hypochaeris meyeniana is characterized by retrorsely pinnatifid leaves (rarely lobate) and slightly narrower cypselar apices. Hypochaeris hohenackeri (Sch. Bip.) Domke and H. taraxacoides Ball are glabrous, whereas H. acaulis (J. Rémy) Britton has scattered shaggy trichomes on the leaves; all three occur in humid places, such as seeps or bogs. Hypochaeris eriolaena (Sch. Bip.) Reiche and H. mucida Domke are pubescent, with long whiplike trichomes on leaves and phyllaries, giving a niveous-tomentose appearance. Hypochaeris echegarayi Hieron. (white corollas) and H. eremophila Cabrera (yellow corollas) are two related species with shaggy trichomes on the abaxial surfaces of the phyllaries, both with considerable ecological tolerance, that grow in dry as well as humid sites. Morphological cladistic analyses suggest a hypothesis of relationships within the complex. Surprisingly, H. acaulis from Chile and Argentina, although fitting morphologically within the H. sessiliflora complex, based on amplified fragment length polymorphism (AFLP) data, clearly does not seem to belong to this group. Instead, the species ties to H. palustris (Phil.) De Wild. and H. tenuifolia (Hook. & Arn.) Griseb., also from the southern Andes. The acaulescent habit of H. acaulis seems best interpreted as a parallel adaptation to survival at high elevations.
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