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

12. Decalobanthus korthalsianus (Ooststr.) A.R.Simões & Staples View in CoL — Map 5 View Map 5

Decalobanthus korthalsianus (Ooststr.) A.R. Simões & Staples (2017) View in CoL 571. — Merremia korthalsiana Ooststr. (1938) View in CoL 175. — Type: Korthals 237 (holo on 2 sheets L [L.0004236, L.0004237]), ( Indonesia, Kalimantan Selatan, Dusun,) ‘ Dutch S.E. Borneo , Doesoen’ .

Stems and branches drying angular substriate, not lenticellate; young parts puberulent, later glabrate. Leaves basally attached, broadly ovate or orbicular, 6–15 by 4–14 cm, bases broadly and shallowly cordate or truncate; secondary veins 7–10 on either side of the midvein. Inflorescences corymbose, many-flowered, crowded, appearing ± flat-topped; peduncles 12–20 cm long; lower bracts foliaceous, 1.5–4 cm long, upper bracts linear-subulate, 2.5–4 mm long, pubescent. Flower buds ovoid, acutish; sepals equal or outer slightly shorter, broadly elliptic or orbicular, 0.9–1 cm long, black when dry, shining, apex broadly rounded; corollas broadly funnelform or campanulate, 2–2.5 cm long, yellow, limb shallowly lobed, glabrous outside; stamens included; pistil included. Fruits and seeds not seen.

Distribution — Endemic to Borneo: Malaysia ( Sarawak), Indonesia ( Kalimantan Barat, K. Selatan).

Habitat & Ecology — Mostly in secondary forests; elevation between 150–300 m.

Vernacular name — Malaysia: akar solop ( Sarawak; Richards 2219).

Note — It has been suggested (A.R. Simões, pers. comm.) that this taxon may be conspecific with D. clemensianus . However, after careful examination of the few older collections (just four) that are available, I am maintaining this taxon. In my expe- rience Van Ooststroom had an exceptional ‘eye’ for recognizing and delimiting species on morphological criteria and I trust his judgement. But in a parallel situation with D. crassinervius , there are just a few older collections that can confidently be assigned to D. korthalsianus and there are no recent collections that correspond with them. Why is that? When new collections and molecular samples can be made there will be new insights into species delimitation in Decalobanthus .