Decalobanthus crassinervius (Ooststr.) A.R.Simões & Chatrou

7. Decalobanthus crassinervius (Ooststr.) A.R.Simões & Chatrou — Map 5 View Map 5

Decalobanthus crassinervius (Ooststr.) A.R.Simões & Chatrou in Simões et al. (2020: 55) 5. — Merremia crassinervia Ooststr. (1939b) 350. — Type: Haviland & Hose 3523E (holo L [ L 0004224 ];iso K [ K000830846 ] as 3523K, SAR as 3523A), ( Malaysia, Sarawak, Betong ,) ‘ Saribas, Paku’.

Stems and branches pale lenticellate. Leaves basally attached, ovate to broadly ovate, 7–13 by 3.5–9 cm, bases cordate; secondary veins 8–10 on either side of the midvein. Inflorescences many-flowered, corymbose; peduncle 7–11(–17) cm long, terete; lower bracts sometimes foliose, upper bracts minute. Flower buds conical, tapering to an acute apex; sepals subequal, 1.1–1.2 cm long, outer 2 elliptic, convex, apices rounded and mucronulate, subcoriaceous; inner 3 broadly elliptic to orbicular, apices rounded and mucronulate, margins thinner; corolla funnelform, yellow, c. 2–2.5 cm long, glabrous, limb shallowly lobed; stamens and pistil included. Fruits and seeds unknown.

Previously published illustration — Van Ooststroom (1939b: 296, f. 1a).

Distribution — Endemic to Borneo: Malaysia ( Sarawak).

Habitat & Ecology — Along a stream in shady, logged over forest; in secondary forest near a riverbank; along a logging road; on yellow clay soil. Elevation 70 m.

Note — Superficially, D. crassinervius resembles D. bimbim in terms of the narrow, tapering acute flower buds and leaf venation, but the leaf shape and texture are different and the inflorescence architecture even more so. Still known from only five collections (one unconfirmed), all from remote parts of Sarawak, D. crassinervius remains an enigmatic species.