Abstract Detail

Systematics Section/ASPT

Ballard, Harvey [1], Paula Souza, Juliana [2], Wahlert, Gregory [3], Flicker, Benjamin [4].

Dismantling the polyphyletic genera Hybanthus and Rinorea (Violaceae): A progress report.

Our recent molecular phylogenetic studies on the Violaceae have demonstrated polyphyly in the genera Hybanthus Jacq. and Rinorea Aubl., and morphological characterization of segregate genera is proceeding. Nine genera are being circumscribed from Hybanthus and three, from Rinorea. Morphological studies of the type species, Hybanthus havanensis Jacq., and two related species in Hybanthus sensu stricto are quite anomalous in numerous traits across the plant body, including suffruticose or subarborescent form, ridged branches, long-pedunculate dichasium, bottom petal distended into a pouch, fully connate filaments, staminal glands fused into a shield-like process, and asymmetrical capsules with 1 brown seed. The genus is restricted to Mesoamerica and the Antilles. Other hybanthoid groups are readily distinguished by features of growth form, foliage, inflorescence, floral zygomorphy, petal differentiation, androecium, capsule and seed, as well as differences in chromosome number and calcium oxalate crystal morphology and distribution. Temperate eastern North American H. concolor will be placed in the resurrected monotypic genus Cubelium Raf. ex Britton & A.Br. Two Mexican and Central American species are transferred to the new genus Ixchelia. Two Central American species of the Hybanthus guanacastensis group will have their own, as yet unnamed, genus. Two species of the Hybanthus fruticulosus group in western Mexico will be transferred to the new genus Mexion. Five to six species in the widely distributed Latin American Hybanthus thiemei group will have their own genus. The remaining 60 New World species will be transferred to the resurrected genus Pombalia Vand. Two Old World segregates are represented by the new genus Afrohybanthus with 23 species in Africa, Madagascar, India and Australasia; and the resurrected genus Pigea DC., to contain 15 species in southern Australia and the southwest Pacific islands. In the Rinorea assemblage, a distinctive transitional lineage of three species representing Hekking's informal Apiculatae group is being segregated as a new genus in southern Central America and adjacent South America. A pair of suffruticose species comprising the Rinorea virgata group in subtropical southwest Asian has occasionally been segregated (by regional taxonomists) as Scyphellandra Thwaites. Unfortunately the earlier generic name Dioryktandra Hassk. must replace Scyphellandra. The anomalous Rinorea uxpanapana, mentioned above, is transferred to the new genus Ixchelia. Contrary to the situation with Hybanthus sensu stricto, the bulk of species recently assigned to Rinorea is retained, with a number of distinctive morphological lineages corresponding to phylogenetic clades eventually recognized as infrageneric groups.

1 - Ohio University, ENVIR & PLANT BIOLOGY-PORTER H, 315 Porter Hall, Athens, OH, 45701-2979, USA
2 - Universidade de São Paulo, , Instituto de Biociências, Cidade Universitária, São Paulo, 05508, Brazil
3 - University of Utah, Department of Biology, Salt Lake City, UT, 84112, USA
4 - Ohio University, Department of Environmental and Plant Biology, 315 Porter Hall, Athens, OH, 45701, USA

Keywords:
Violaceae
generic circumscription
Polyphyly.

Presentation Type: Oral Paper:Papers for Sections
Session: 18
Location: Salmon/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 10:30 AM
Number: 18010
Abstract ID:474
Candidate for Awards:None