Vavilovia formosa (Steven) Fed., an intriguing Pisum relative

Vavilovia formosa (Steven) Fed., a small, patch-forming perennial found in upper-alpine screes of the Caucasus, eastern Turkey, northern parts of Iraq, Iran, Syria and Lebanon. Unlike Pisum, the leaflets of Vavilovia unroll rather than unfolding (supervolute rather than conduplicate vernation), and it is a perennial, rhizomatous plant. In these respects and in its ecology, Vavilovia markedly differs from wild and cultivated Pisum and resembles Lathyrus. Species relationships were determined for 31 species of tribe Fabeae using sequences for four regions known to be informative for the group ; the maturase K, trnL-F and trnS-G spacer regions of chloroplast DNA, and the internal transcribed spacer (ITS) region of nuclear DNA. Maximum parsimony and Bayesian analysis of combined sequence data confirmed Vavilovia as a separate group positioned between Lathyrus and Pisum.