Morphological and anatomical development in the Vitaceae. III. Vegetative development in Parthenocissus inserta

The vegetative shoot of Parthenocissus inserta (Kerner) Fritsch. was examined both histologically and three dimensionally. The shoot apex produces uncommitted primordia at two nodes of a three-node, five-primordium cycle. The primordia can be summarized as follows: (i) a leaf opposite a lower uncommitted primordium, arising above a leaf and low on the apical flank; (ii) a leaf either opposite an upper uncommitted primordium or without an uncommitted primordium opposite it, in both instances arising directly above an uncommitted primordium and high on the apical flank; (iii) a lower uncommitted primordium, arising above and opposite a leaf and high on the flank of the apex; (iv) an upper uncommitted primordium, arising above and opposite a leaf and low on the flank of the apex. The uncommitted primordium may develop into either an inflorescence or a tendril. Tendril growth is sympodial, usually with three orders of branching. Tendrils may, on occasion, develop adhesive discs at their tips, but most commonly the tips disintegrate. Axillary buds are present at the upper tendril node and the tendrilless node. Their initiation is more precocious at the tendrilless node. The pattern of development is the same for both, in that both form multiple orders of buds, each in the axil of the prophyll of the preceding one.