Leaf architecture in Adansonia, Bombax and Celiba (Bombacaceae)

Abstract

Leaf architecture was investigated in three species of the family Bombacaceae. The mature leaflets from both fresh and herbarium materials were cleared using the method of Mohan Ram and Nayyar (1977), and terminologies of Hickey (1973) were used to determine the leaf characters and the venation patterns. The whole lamina is more or less symmetrical in all the species investigated. The major venation pattern conforms to the types of camptodromous mixed with festooned brochidodromous, and festooned brochidodromous. In all the members of the family studied, the primary and secondary veins are ornamented with parenchymatous bundle sheaths. Imperfectly developed areoles are predominant over the developed ones. The size and the shape of the areole is variable. The vein endings may be simple, or once or sometimes twice dichotomously branched. The highest venation order of the family is sixth degree. Marginal ultimate venation is looped. Tracheids are either uni-, bi-, tri-, or multi-seriate and vary in shape and size, and are commonly found at the free ends of the veins. Extension cells and isolated tracheids are not common. These characters are remarkably different from those in members of the Malvaceae.