ONOTOGENY OF AXILLARY AND ACCESSORY BUDS IN CLERODENDRUM PHLOMIDIS L

Plastochronic changes in the vegetative shoot apex and origin and development of axillary and accessory buds are studied.The flat shoot apex shows structural and dimensional changes in a plastochron. They are described in three phases, the pre-leaf initiation, the leaf initiation, and the post-leaf initiation. The youngest axillary bud meristem is identified near the axil at the second node when the subtending leaf primordium is 200-12 μ long. The corpus of the bud meristem has a more active role in bud development than has the tunica layers. The shell zone associated with a young bud meristem persists until the bud has attained the structural and functional attributes of the main shoot apex. It loses its histological identity by producing derivatives which merge with the ground tissue and procambial cells of bud traces. In a developing bud the provascular system of the bud appears as an arc, a loop, or as a ring in transverse sections at different levels. These configurations are composed of anastomosing procambial strands of bud trace and residual meristem, both being differentiated from developing bud meristem. © 1969 OXFORD UNIVERSITY PRESS.