Abstract
A new species, Lysimachia septemfida (Primulaceae), from Yunnan (Southwest China) is described and illustrated. The new species exhibits several unusual characters in Lysimachia including lack of a corolla, 7-merous flowers, leaves in whorls of 3 and distinct multicellular nodiferous hairs, which make it readily distinguishable from all other species in this genus. The diagnostic differences between this new species and its suppositive allies are given. In addition, the systematic placement of this new species is also discussed based on an ITS molecular tree.