Bauhinia semibifida

Author: Roxb.

General note
This is the most widely distributed species of the Malesian Bauhinia 's 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. Larsen & Larsen (1996: 490) have separated out 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 this species 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 Bauhinia aherniana Perkins, which is undoubtedly a closely related species.
Besides the varieties described below some of the variations are worth while mentioning. The stigma is usually large and peltate, from Sabah Larsen & Larsen (1996) have measured 8 mm across 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 Larsen & Larsen (1996) have measured 15 mm, lengthening to 20 mm after anthesis. Larsen & Larsen (1996) have found a collection from Sumatra with a long hypanthium and a small, almost capitate stigma; while on 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 which is first of all characterized by the tubular hypanthium dilated at base. The flowers are white turning yellowish or yellowish-green and the stigma is large and peltate, oblique.

KEY TO THE VARIETIES (semibifida Bauh lv+buds FM11 )
1a.   Hypanthium 5-10(-15) mm long, tubular, dilated at base; leaves with tip of lobes obtuse to acuminate; indumentum varying    2
1b.   Hypanthium shorter, 5 by 4 mm, ± urceolate; leaves finely reddish brown pubescent below, tip of lobes obtuse Bauhinia semibifida bruneiana    
2a.   Bracts large, 2-30 mm; young branches patently hairy; leaves reddish villous beneath    Bauhinia semibifida longebracteata
2b.   Not this combination    3
3a.   Leaves on flowering shoots 4-11 cm across, rarely more    4
3b.   Leaves on flowering shoots larger, 11-18 cm across    5
4a.   Leaves glabrous to glabrescent below; divided 1/4-1/2, tip of lobes obtuse to subacute, rarely acute    Bauhinia semibifida semibifida
4b.   Leaves densely dark brown appressed hairy below, deeply divided, 2/3-3/4, lobes narrowly triangular, tip acuminate Bauhinia semibifida acuminata    
5a.   Inflorescence racemes 20-30 cm long Bauhinia semibifida stenostachya
5b.   Inflorescence corymbose to racemose, up to 20 cm long   
Bauhinia semibifida perkinsae

a. Bauhinia semibifida Roxb. var. semibifida (Bauhinia semibifida semibifida )

Morphological description (see also description of Genus Bauhinia ; Subgenus Phanera and Section Phanera )
Tendrilled climber , young branches brownish pubescent, later glabrous (semibifida Bauh ylf JRN 5-7).

Leaves: stipules (semibifida Bauh stipules 139510) auriculate to orbicular, c. 5 by 2 mm, glabrous or nearly so; petiole 2-6 cm, pubescent to glabrous, lamina obovate-orbicular, 4-11 cm diam; (9-)11-13-nerved; bifid 1/4 - 2/5, tips of lobes obtuse (to acute), base cordate; upper surface glabrous, lower glabrous to glabrescent (semibifida Bauhinia lvs 139510).

Inflorescence terminal or lateral, short or long racemes with pubescent axis; pedicels pubescent, 3-6 cm; bracts lanceolate, silky puberulous, 5-8 mm, very early caducous; bracteoles linear-acute, c. 8 mm (semibifida Bauh infl&pod 139511).

Flowers: Buds (semibifida sem Bauh buds FM11 ) ellipsoidal, clavate, mostly pubescent, 10-24 mm long. Hypanthium tubular, 5-10(-15) mm long, with dilated base. Calyx early splitting into 5 reflexed, strap-shaped sepals, 1-2.5 cm long. Petals white turning yellow, unequal, elliptic to oblong, glabrous except for the pubescent claw, and sometimes sparsely hirsute externally along the median line, 2-3(-3.5) cm long, claw 2-5 mm. Stamens 3 fertile; filaments 2.5-3 cm, glabrous, stout; anthers oblong, 1 cm, opening by a longitudinal slit; staminodes 2-3, small, filiform. Stipe of ovary c. 3 mm, ovary c. 10 mm, style stout, c. 5 mm, all entirely densely brown silky tomentose; style increasing towards the very large oblique, peltate stigma, up to 5 mm across, much lengthening after anthesis.

Pods strap-shaped, flat, smooth, oblong, glabrous, 10-20 by 3-4 cm, beak 5-10 mm (semibifida Bauh infl&pod 139511).

Seeds c. 6, flat, varying in size.

Malesia : Sumatra, Malay Peninsula, Borneo, Philippines, Celebes. One of the most widespread species in the genus.

In margin of forests, 200-2000 m altitude.

Vernacular names
Kupu (W Borneo, Pontianak); Takui lebang (Sungei); Akar kati katwi (Sumatra, Mt Ophir), Andor sibola ringring (Asahan), Bulun siduaja (Simalur), Akar pulalang (Jambi), Ganggang katup (Lingga).

Powder of roots used for medicinal purposes.

b. Bauhinia semibifida Roxb. var. acuminata K. & S. S. Larsen (Bauhinia semibifida acuminata ; semibifida ac Bauh lf FM11 )

The deeply divided leaves , 2/3 to 3/4 with broad sinus and narrowly triangular lobes with acuminate tips are the easily distinguishing characters of this variety. Lamina 4.5-10 by 4-7 cm, the undersides are densely dark brown appressed hairy. The buds are clavate, 13-14 mm, hypanthium 5-7 mm. Petals are narrow lanceolate, 15-20 mm including the thin, 4-5 mm long claw.

Malesia : N Borneo. Type from Sabah (Sepulut), another collection from NE Borneo (Berau, Mt Njapa).

No data available.

On the holotype the petals are described as 'reddish/yellow'; this should be studied in nature as all other varieties have white petals turning yellowish.

c. Bauhinia semibifida Roxb. var. bruneiana K. & S.S. Larsen (Bauhinia semibifida bruneiana ; semibifida brun Bauh bud FM11 )

All young parts are covered with short, ferrugineous hairs. The leaves on sterile shoots are divided 1/2, tip of lobes obtuse, 7-nerved, 7.5-12 by 7-11.5 cm; on flowering shoots smaller, 1/3 - 1/2 divided, 3-4.5 by 3-5 cm, finely reddish pubescent beneath. Inflorescence ferrugineous velvety; bracts narrow linear-lanceolate to acuminate, 10-12 mm; bracteoles much narrower; pedicels 6-7 cm; hypanthium ± urceolate, 5 by 4 mm; buds club-shaped, 2-3 cm, with short, free tips of the sepals. Petals ferrugineous silky hairy outside along the midline.

Malesia : Borneo (Brunei, Sabah and Sarawak).

Lowland evergreen forest.

The type is from Brunei; one collection from Sabah has a similar indumentum, but petals less hairy and the larger leaves have more acute lobes; this is also the case with a collection from near Kuching.

d. Bauhinia semibifida Roxb. var. longebracteata K. & S.S. Larsen (Bauhinia semibifida longebracteata ; semibifida long Bauh bud FM11 )

This variety is recognizable by its young branches being shaggy, patently ferrugineous hairy. The bracts are narrowly lanceolate to linear, 2-3 cm, tardily caducous. Leaves are rather thin reddish villous beneath. The petals are narrowly lanceolate, silky hairy on the outer side. The stigma is smaller than in the other varieties.

Malesia : Borneo. The type is from W Borneo (Melaku) and there is one more collection from Central Borneo (Bukit Raja).

Disturbed dipterocarp forest at low altitude.

e. Bauhinia semibifida Roxb. var. perkinsae (Merr.) K. & S.S. Larsen (Bauhinia semibifida perkinsae )

Resembles var. stenostachya but has shorter, corymbose to racemose inflorescence , smaller flowers and a shorter hypanthium. The leaves are densely reddish-brown hairy, particularly when young.

Malesia : Philippines, endemic to Palawan where a dozen collections have been made.

At low altitudes on sandy soil.

f. Bauhinia semibifida Roxb. var. stenostachya (Baker) K. & S.S. Larsen (Bauhinia semibifida stenostachya )

Morphological descritpion
Leaves large, 1/4 to 1/3 bifid, 13-17-nerved, up to 18 cm across; base deeply cordate; upper surface glossy, lower dark brown woolly pubescent, sometimes only on the nerves.

Inflorescence long, narrow, many-flowered racemes, 20-35 cm; pedicel sturdy, up to 4 cm, hairy; bracts narrowly lanceolate, c. 10 mm; bracteoles narrower and smaller.

Flowers: Buds clavate, apiculate, up to 2 cm. Hypanthium 10-13 mm, grooved, silky brown pubescent.

Malesia : Borneo (Sabah, Sarawak).

Primary forests at low altitudes, river banks.

The type is from Sabah; two collections of Clemens from Sarawak are referred to this variety even if they are more glabrous.