Comparative Study of Leaf Architectural and Epidermal Features in Some Nigerian Species of Bombacaceae
Foliar architectural and epidermal studies were conducted on some species in the family Bombacaceae in search of taxonomic and diagnostic characters that could be employed for their classification and identification. Lamina symmetry, leaf form, leaf apex, leaf base, leaf margin, leaf texture, petiole, venation pattern and areolation were studied as the architectural features. Diagnostic architectural characters that distinguish Ceiba pentandra from Bombax species are acute leaf base, pinnate camptodromous venation and veinlets branching three times. Using leaf epidermal characters, the presence of wavy anticlinal wall and cuticular striations delimit Ceiba pentandra from Bombax species. Elliptic leaf form, decurrent leaf base, toothed margin, normal petiole, primary vein size stout 2-4%, veinlets branched twice, well developed and oriented areolation are diagnostic to Adansonia digitate based on the leaf architectural features and the presence of stellate trichome and large stomatal size are the epidermal characters that delimit A. digitata from all the other species in Bombacaceae. Diagnostic features of Bombax species are reported and similarly, the taxonomic characters for all the species in Bombacaceae are symmetrical lamina, coriaceous leaf texture, variation in angle of divergence nearly uniform, epidermal cell polygonal to irregular in shape and hypostomatic stomata. Taxonomic key was conducted based on the characters studied.