Bauhinia semibifida
Taxonomy
This is the most widely distributed species of the Malesian Bauhinias and a great many collections have been available to us. It is a highly polymorphous species, composed of numerous isolated populations. There is, however, a continuous variation from small to large leaves with a varying indumentum and varying bud shapes with long to short hypanthium. We have separated some of the more remarkable local 'types' as varieties. Local floras may well in the future distinguish more, and some may even be tempted to treat these as species, as has been the case with, e.g., B. perkinsae and B. stenostachya.
The best character for recognizing Bauhinia semibifida is the distinctly dilated hypanthium.
Bauhinia excurrens Stapf, regarded as a variety by De Wit, is treated as a separate species and B. subglabra Merr. is regarded as belonging to B. aherniana Perkins, which undoubtedly is a closely related species.
Besides the varieties described below some of the variations are worthwhile mentioning. The stigma is usually large and peltate; from Sabah we have measured 8 mm in diameter in a herbarium specimen. Also the anthers are large and 15 mm is the largest measure, again from Sabah. The hypanthium varies quite a lot, it measures usually c. 10 mm, in large-flowered specimens from N Borneo we have measured 15 mm, lengthening to 20 mm after anthesis. We have found a collection from Sumatra with a long hypanthium and a small, almost capitate stigma; while in the Philippines the hypanthium tends to be short, 5-6 mm and only slightly dilated; this is combined with generally smaller flowers. The great majority of all the collections, however, falls within var. semibifida, first of all characterized by the tubular hypanthium dilated at the base. The flowers are white, turning yellowish or yellowish green, and the stigma is large and peltate, oblique.
The best character for recognizing Bauhinia semibifida is the distinctly dilated hypanthium.
Bauhinia excurrens Stapf, regarded as a variety by De Wit, is treated as a separate species and B. subglabra Merr. is regarded as belonging to B. aherniana Perkins, which undoubtedly is a closely related species.
Besides the varieties described below some of the variations are worthwhile mentioning. The stigma is usually large and peltate; from Sabah we have measured 8 mm in diameter in a herbarium specimen. Also the anthers are large and 15 mm is the largest measure, again from Sabah. The hypanthium varies quite a lot, it measures usually c. 10 mm, in large-flowered specimens from N Borneo we have measured 15 mm, lengthening to 20 mm after anthesis. We have found a collection from Sumatra with a long hypanthium and a small, almost capitate stigma; while in the Philippines the hypanthium tends to be short, 5-6 mm and only slightly dilated; this is combined with generally smaller flowers. The great majority of all the collections, however, falls within var. semibifida, first of all characterized by the tubular hypanthium dilated at the base. The flowers are white, turning yellowish or yellowish green, and the stigma is large and peltate, oblique.
Citation
Wall. 1832 – In: Pl. As. Rar.: pl. 253
Ridley 1922 – In: Fl. Malay Penins.: 627
Wight. 1840 – In: Ic. Pl.: pl. 263
Wunderlin, Larsen & Larsen 1987 – In: Biol. Skr. Dan. Vid. Selsk.: 19, 20.
Prain 1897 – In: J. As. Soc. Beng.: 182, 184, 185, 499, 502
Baker 1878 – In: Hook.f., Fl. Brit. India 2: 280
Roxb. 1874 – In: Fl. Ind.: 348
Miq. 1855 – In: Fl. Ind. Bat.: 61
Gagnep. 1913 – In: Fl. Indo-Chine: 130
de Wit 1956 – In: Reinwardtia: 465.