Dioscorea scortechinii Prain & Burkill, a new record for Thailand and its infraspecific variation

Abstract

Dioscorea scortechinii Prain & Burkill is a compound-leafed species with significant infraspecific variation in floral organ size and shape across its broad, but scattered distribution in
South-East Asia. Previous classifications included a distinct variety (var. parviflora Prain & Burkill) at the northern end of its range in China and Vietnam. Its discovery in Thailand has allowed the distribution of the species as a whole to be clarified. The specimens available from China and Vietnam have tepals which are at the smaller end of a continuous range of size variation and thus the variety does not appear
to merit recognition. A full description, illustrations and a provisional conservation assessment are given. The relationships of D. scortechinii with the mainly Philippine taxa of D. sect. Botryosicyos (Hochst.) Uline with capsules greater than 25 mm long which do not fully reflex, and which often have
thicker leaves with very prominent veins on the lower surface, are suggested to be in need of detailed systematic study.