Frequency of anastomosis, types of vein anastomosis, and their pattern of distribution in the standard, wing, and keel of four species (Butea frondosa Wall., Cajanus cajan (Linn.) Millsp., Dolichos lablab Linn., and Erythrina indica Zoll.), from four different subtribes of the tribe Phaseoleae (Leguminosae) have been analysed. It has been found that the species differ considerably in these respects. The differences have been found to be significant and species-specific, having a very small range of variation within a species. It is suggested that this specificity in the distribution of vein anastomosis pattern in petal sectors may be useful in tracing phylogeny. © 1968 OXFORD UNIVERSITY PRESS.