Studies of Asian ‘Calliandra' lead to expansion of Sanjappa (Fabaceae-Caesalpinioideae)

The genus Sanjappa, previously with the single species S. cynometroides in southern India, is expanded to include S. umbrosa, comb. nov., in northeastern India, Bangladesh, Myanmar and China (Yunnan) and S. vietnamica, sp. nov., in southern Vietnam. Sanjappa differs from Thailentadopsis, its sister genus in the Zapoteca clade, by having leaves with extrafloral nectaries in the form of sessile (versus stipitate) glands and elastically dehiscent, not moniliform pods (versus pods not elastically dehiscent and submoniliform). Sanjappa umbrosa and S. vietnamica differ from S. cynometroides by having bipinnate leaves with one pair of pinnae (versus simply pinnate leaves with two leaflets only) and a four-lobed (versus three-lobed) corolla. In S. umbrosa each pinna is 2–3-foliolate and paired stipular spines are mainly present on younger growth, whereas in S. vietnamica each pinna is (3–)4–5-foliolate and branches, including major ones, are armed with numerous paired spines with thickened bases. Synonymies, images and notes on distribution, habitat, taxonomy and conservation for the three species of Sanjappa are provided, and all names are typified. With the taxonomic changes proposed here, all Asian species previously treated as members of Calliandra have been accommodated outside this genus.