Phytotaxa 277 (1): 047–058 ISSN 1179-3155 (print edition) http://www.mapress.com/j/pt/ PHYTOTAXA Copyright © 2016 Magnolia Press Article ISSN 1179-3163 (online edition) http://dx.doi.org/10.11646/phytotaxa.277.1.4 A new variety of Panax (Araliaceae) from Lam Vien Plateau, Vietnam and its molecular evidence NONG VAN DUY1, LE NGOC TRIEU2, NGUYEN DUY CHINH2 & VAN TIEN TRAN2* 1Tay Nguyen Institute for Scientific Research, Vietnam Academy of Science and Technology, 116 Xo Viet Nghe Tinh, Dalat City, Lam Dong Province, Vietnam 2Faculty of Biology, Da Lat University, 01 Phu Dong Thien Vuong, Dalat city, Lam Dong Province, Vietnam *Author for correspondence: E-mail:
[email protected] Abstract A new variety of Panax, P. vietnamensis var. langbianensis is described from Lang Bian Mountain, Lam Vien Plateau in southern Vietnam. It is visually distinct from other two varieties of P. vietnamensis (var. vietnamensis, var. fuscidiscus) by having the shorter petiolules 8–11 mm long, leaflet apex acuminate, pedicels 0.4–0.6 cm, petals smaller, disk prominent, and styles typically 2 (or rarely 1). The recognition of the new variety is supported by the evidence of molecular sequence data from three markers (ITS1-5.8S-ITS2, 18S rRNA and partial matK) in addition to morphological consideration. The new variety is known only from one population from the locality where the type specimens were collected. The species occurs in an area of only approximately 1 km2 with a population size of approximately 100–200 individuals. Therefore it should be regarded as critically endangered (CBB2acb (ii,iii,v); C2a(i); E) according to the IUCN Red List Categories and criteria.