Abstract
The study of the floral anatomy of some common Indian species of the tribe Plumiereae (Apocynaceae) supports the conclusions derived from the study of chromosomes and secondary xylem, which are: (1) Holarrhena are distinct from Ervatamia and should be placed in Alostoniinae (Schumann, 1895) and not under Tabernaemontaninae (Bentham and Hooker, 1876). (2) Different subtribes possess distinctive features; and, therefore, the classification into subtribes is justified. (3) Tabernaemontaninae are the most primitive subtirbe from which the others can be derived. (4) Alstoniinae are heterogeneous and are composed of different evolutionary lines. (5) The genus Plumeria stands isolated in tribe Plumiereae and needs separation as a new taxon.