Decalobanthus pulcher (Ooststr.) A.R.Simões & Staples

17. Decalobanthus pulcher (Ooststr.) A.R.Simões & Staples — Map 12

Decalobanthus pulcher (Ooststr.) A.R. Simões & Staples (2017) 571. — Merremia pulchra Ooststr. (1939b) View in CoL 348. — Type: G.K. Gns 14 (holo SING [ SING0052313 About SING ]), ( Brunei, Muara district ,) Brunei Bay.

Stems and branches glabrous, lenticellate. Leaves basally attached, ovate, 7–11 by 5–6.5 cm, rugose, drying bicoloured: blackish adaxially, reddish brown abaxially, bases cordate; secondary veins 6–7 on either side of the midvein. Inflorescences fundamentally cymose, or aggregated in raceme-like clusters, or flowers solitary; peduncles c. 3–6 cm, terete. Flower buds ellipsoid, obtuse; sepals oblong to elliptic-oblong, 2.5–3 cm long, apices obtuse; corollas broadly funnelform, c. 6 cm long, bright yellow, glabrous. Fruiting calyxes accrescent, spreading from fruit. Fruits indehiscent, berry-like, depressed globose, 1.8– 2 cm diam, ridged, brown-black, apex with indurate style base. Seeds up to 11, carinate, 6–7 mm long, brownish, glabrous.

Previously published illustration — Van Ooststroom (1939b: 349, f. 3a–c).

Distribution — Endemic to Borneo: Brunei, Malaysia ( Sarawak, Labuan Island). Not found, so far, in Sabah; an unlocal- ized report from the southern Philippines (mentioned by Van Ooststroom & Hoogland 1953: 451) remains unconfirmed.

Habitat & Ecology — In belukar (secondary forest regrowth), along roadsides, trailing on bare soil and in grass vegetation, in hill dipterocarp forest along logging road, in mossy high forest, primary lowland forest; soils include heavy clay, ultisol, igneous derived soil, dacite spur; elevation: 20–850(–1100) m.

Vernacular names — Brunei: Akau belaan (Dusun; Voeks RV­552), akar melabok (Iban; Nangkat NN­148).

Uses — The mature fruits said to have an oily exudate or sap used in the past for shampooing hair ( Nangkat NN­148); flower bud extract (used) as hair oil ( Voeks RV­552).

Note — One of the most spectacular species, with large, bright golden yellow blossoms. Collectors report the vines at- tain 100–120 feet in length ( Anderson & Paie S.28489, Ashton S.19005). The indehiscent fruit with many seeds is an anomaly in the family. Perhaps the collection in which it was observed is abnormal in terms of fruit development; it was one of the only fruiting specimens studied.