Abstract:
Bauhinia pottsii G.Don is a shrub which occurs naturally along the edge of evergreen forest below 200 meters ASL. In Thailand, five varieties of this species were recorded : B.pottsii var. pottsii G. Don, B.pottsii var. velutina (Wall. ex Benth.) K. & S.S. Larsen, B.pottsii var. mollissima (Wall. ex Prain) K. & S.S. Larsen, B.pottsii var. subsessilis (Craib) de Wit, and B.pottsii var. decipiens (Craib) K. & S.S. Larsen. Each variety exhibits somewhat a wide range of morphological plasticity. In order to clarify their taxonomic status, all varieties except B.pottsii var. decipiens which was not found, were investigated by numerical taxonomic studies, consisting of 3 multivariate analyses, namely factor analysis, cluster analysis and discriminant analysis. These analyses focused on morphological characters as follows: 7 characters of leaf, 41 characters of flower and 11 characters of pollen as well as 36 characters from 6 isozyme systems (acid phosphatase, esterase, glutamate oxaloacetate transaminase, malate dehydrogenase, perxidase and shikimate dehydrogenase). The results show that this species should be classified into 3 groups -- i) B.pottsii var. pottsii, ii) B.pottsii var. subsessilis, and iii) B.pottsii var. velutina and B.pottsii var. mollissima-based on 3 characters of flower, 2 characters of pollen and 14 characters from isozyme pattern. To compare taxonomic status with B.purpurea and B.acuminata by analyses 74 morphological characters of leaf, flower, pollen, pod, and seed by the same techniques. The results from morphological characters alone suggest that 3 groups of B.pottsii should be recognized as 3 distinct varieties: i) B.pottsii var. pottsii, ii) B.pottsii var. subsessilis and iii) B.pottsii var. velutina