Resolving Generic Boundaries in Indian-Australasian Cleomaceae: Circumscription of Areocleome, Arivela, and Corynandra as Distinct Genera

Abstract

Novel molecular data and morphological studies have provided support for the segregation of numerous genera from Cleome s. l. (Cleomaceae). Corynandra has been proposed as a segregate genus including Indian and Australian species based on floral and seed morphology. Contrasting seed coat micro-morphology between Indian and Australian species included in Corynandra raised questions over the monophyly of that genus concept. Relationships among the Indian and Australian species remain unclear due to limited sampling in previous molecular analyses. We expanded the sampling of taxa from India and Australia in order to clarify relationships between these species and the circumscription of Corynandra. Comprehensive sampling of Indian and Australian species formed three well-supported clades based on analyses ofmolecular sequence data and we conclude that Corynandra is not related to the Australian species. The genus Arivela Raf. is reinstated for the majority of Australian species. The new genus Areocleome is described to accommodate the unusual Australian C-4 species Cleome oxalidea. The following new combinations are made: Areocleome oxalidea, Arivela arenitensis, Arivela bundeica, Arivela cleomoides, Arivela insolata, Arivela kenneallyi, Arivela limmenensis, Arivela linophylla, Arivela lophosperma, Arivela microaustralica, Arivela tetrandra, Arivela uncifera, Corynandra aspera, and Corynandra simplicifolia. Arivela microphylla is raised to species level and provided with a new combination.