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

6. Decalobanthus clemensianus (Ooststr.) A.R.Simões & Chatrou — Fig. 4 View Fig ; Map 4

Decalobanthus clemensianus (Ooststr.) A.R.Simões & Chatrou in Simões et al. (2020) 55: 5. — Merremia clemensiana Ooststr. (1939b) 350. — Type: J. & M.S. Clemens 21133 (holo BO [BO 177795]; iso A [00054674], B†, BISH [BISH1001147],K [K000830845],L [L0004223,L 0640533],MO [MO-989044], NY [NY 336580, NY 336581], P [P00622203], SAR), Malaysia, Sarawak, ‘upper Rejang River, Kapit’.

Decalobanthus gracilis (E.J.F.Campb. & Argent) A.R.Simões & Chatrou in Simões et al. (2020: 55) 6. — Merremia gracilis E.J.F.Campb. & Argent (1988) 345. — Type: Argent & Campbell 411854 (holo SAN; iso A [00054677], BM [ BM000797174 ], E [ E00273914 ],K n.v., L n.v.), Malaysia, Sabah, Lahad Datu distr., Ulu Segama, Danum Valley Field Centre .

Stems and branches angled-striate, bark cracking, glabrous, not lenticellate. Leaves basally attached, ovate to broadly ovate, 5–14 by 3–10 cm, bases rounded to truncate or emarginatesubcordate; secondary veins 5–7 on either side of the midvein. Inflorescences many-flowered, corymbose, ± secund; lowermost bracts often foliaceous, 3–5 cm long, petiolulate, upper bracts and bracteoles caducous. Flower buds ovoid, bases conspicuously angulate, apices acute to obtuse; sepals convex, unequal, outer 2 oblong, 0.6–0.7 cm, bases abaxially with 2 swollen glands, inner 3 longer; corolla campanulate to broadly funnelform, 1.5–2 cm long, yellow, limb crenulate; stamens included, subequal, anthers belatedly spiralling; pistil included, exceeding stamens. Fruiting calyx persistent, slightly accrescent, closely cupping fruit; sepals 0.8–1.1 cm long, blackish brown outside. Capsules globose-ovoid, c. 12–13 mm, 4- or more-valved, septum persistent, papery, valve apices with a sharp, incurved tooth. Seeds 5–6 mm long, black, densely woolly with long brownish or greyish hairs.

Previously published illustration — Campbell & Argent (1988: 346, f. 1, as M. gracilis ).

Distribution — Endemic to Borneo: Malaysia ( Sabah, Sarawak), Indonesia ( Kalimantan Timur, K. Tengah). Not so far reported from Brunei but likely to occur there.

Habitat & Ecology — Scandent and climbing in open situ- ations in thickets, forest margins, and in secondary disturbed vegetation and creeping in cleared areas; elevation 20– 300 m. This species seems to thrive on forest disturbance and has often been collected along logging roads, tractor trails, roadsides, and at the edges of cleared forest. One gets the impression that it is more abundant now than it was when Van Ooststroom (1939b) first described it. A heavy, banana-like fragrance was reported for the flowers ( Argent & Campbell 411854). Personally, I detected no fragrance at all. The seeds often persist in the opened capsules well into the next flowering cycle.

Vernacular names — Malaysia: Bilaran (Dusun-Kinabatan- gan, G.H.S. Wood A 4250).

Note — It is curious that Van Ooststroom (1939b), usually a keen and careful observer, did not mention the prominent sepal glands when he named this species: the glands give the flower buds a distinctive angled or ‘hipped’ appearance. These glands are well illustrated by Campbell & Argent (1988: f. 1, though the captions are reversed for parts C and D). Van Ooststroom cited two duplicates of the type gathering: one in BO and one (now destroyed) in B. Other duplicates of Clemens 21133 that I have studied (not annotated by Van Ooststroom) show the sepal glands. The angled, ‘hipped’ appearance of the calyx is most noticeable on fully mature flower buds; in smaller, less developed buds and in opened flowers (when the sepals are spread outward by corolla anthesis) the basal glands are less noticeable. The sepal glands are very prominent on the type gathering for M. gracilis and there is no doubt that both type gatherings fit on a spectrum of variation.