Foliar venation of some species of Bauhinia L. and Hardwickia binata roxb. (Caesalpinioideae)

Abstract

Recent studies have emphasized the taxonomic importance of venation and its usefulness in classification of the taxon. The present study deals with venation of 12 species of Bauhinia and monotypic genus Hardwickia. Bauhinia shows three types of venation : Acrodromous (B. rufescence, B. retusa, B. phoenicea), Actinodromous (B. galpinii, B. racemosa, B. acuminata and B. tomentosa), Campylodromous (A vahlii, B. hookeri, B. malabarica, B. purpurea and B. variegata). Whereas H. binata show Acrodromous type. Secondary veins forms loops by fusion with the upper secondary veins within the margin of the leaf in some of the species of Bauhinia and also in Hardwickia. Tertiary veins are percurrent, arise at right angles to the secondary veins. Quaternary veins form the well developed areoles. The venation is more uniform in both Bauhinia and Hardwickia and thus establishes the link between the two genera.