Osmophore Development in \u3ci\u3eStanhopea anfracta\u3c/i\u3e and \u3ci\u3eS. pulla\u3c/i\u3e (Orchidaceae)

The developmental anatomy and morphology of the floral scent glands (osmophores) were examined daily from the late bud stage to post-anthesis, for 2 species which are considered to be at opposite poles in the evolutionary development of the genus. The osmophore of S. anfracta was studied using morphometric techniques to estimate volume density of selected cellular inclusions, whereas the osmophore of S. pulla was examined qualitatively. The volume density of starch/amyloplast in S. anfracta remained relatively constant throughout most of the two-day flowering period as did the degree of cell vacuolation. The flower of S. pulla lasts only one day, so similar measurements were not feasible. The osmophore of S. anfracta had a rugose and papillate surface, whereas that of S. pulla was nearly smooth. Epidermal cells comprising the osmophore of S. anfracta were apparently more active in the secretory process than the subepidermal cells, whereas in S. pulla there was no apparent distinction in the relative activity of the different cell layers of the osmophore