Ontogeny of Tendrils in Antigonon leptopus H. & Arn.

In Antigonon leptopus the main tendrillar and axillary branchis a modified inflorescence axis. It usually bears 6–7lateral bracts out of which 3–4 lower ones are small andleaf-like while the upper 2–3 are tendrillar; 2–3tendrils are also present at its terminal end. The vegetativeshoot apex shows a single layer of tunica and an inner massof corpus without any cytohistological zonation. The earliestaxillary bud or tendril meristem arises at the second node andit elongates due to rib meristem activity. The bract primordiaarise in an acropetal succession. The initiation of the bract-tendriland the leafy bract is similar. In the development of the bract-tendril,marginal meristem activity is absent or reduced and the differentiationof the apical and subapical initials is absent. The terminalbract-tendrils arise as lateral appendages and the residuumof the apical meristem of the main axillary tendril persistsfor some time. In the flowering period the floral buds arisein the axils of the bracts and bract-tendrils. No flowers arepresent in the axils of terminal bract-tendrils.