Typification of nine names of Asian species and varieties of Dioscorea (Dioscoreaceae)

Abstract

The yam genus Dioscorea includes some of the world's most important food and medicinal plants The names of most Asian species and infraspecific taxa are in need of typification because their publication predated the 1935 Cambridge Rules of Botanical Nomenclature in which the concept of nomenclatural types was first introduced. Here, the Dioscorea collections cited in the protologues and uncited material associated with the names at their first publications are evaluated in the light of the latest Shenzhen Code (2018) and lectotypes of eight names designated, viz. D. lepcharum, D. nummularia var. glauca, D. pentaphylla var. communis, D. pentaphylla var. linnaei, D. pentaphylla var. malaica, D. pentaphylla var. rheedei, D. pentaphylla var. thwaitesii and D. rogersii. Most of the original materials concerned were collected from India, and the rest from other parts of South Asia and South East Asia (Bangladesh, Sri Lanka, Philippines and Malaysia). The single specimen cited in the protologue of D. wightii Hook.f. is affirmed here as the holotype.