Hydnophytum kebarense Jebb & C.R.Huxley, 2019

21. Hydnophytum kebarense Jebb & C.R.Huxley View in CoL , sp. nov. — Fig. 24 View Fig

Tuber complanatum,ad 15 cm in diametro;superficies laevis, aliquot obtusis spinis ad 0.3 cm longis armata. Caules ex compluribus locis in tubere enati, ad 40 cm longi; internodia alata. Lamina obovata , 3 per 1.4 ad 6 per 2.5 cm, apice rotundato usque acuto-acuminato, basi sensim attenuata; nervi c. 4 vel 6 utrinque; petiolus 0.3 ad 0.8 cm; stipula ad 0.1 cm, processu centrali instructa, caduca. Inflorescentia binata, in caule impressa. Corollae tubus ad 2.5 mm, glaber, lobis ad 1.5 mm longis.

— Typus: Van Royen 5012 (holo L), New Guinea, West Papua Province, Manokwari , Kebar valley , range of hills south of Anjai airstrip , 11 Nov. 1954 .

Etymology. After the type locality.

Tuber flattened, to 15 cm across; with transverse lobing surface smooth, grey to dark-grey. Spines few, obtuse, to 0.3 cm long. Entrance holes scattered, largest on lower surface, ± hidden between adjacent lobes of tuber, darker in colour than surrounding tuber surface, neither lipped nor funnel-like. Cavities large and planar with both smooth-walled and warted surfaces. Stems arising from several places on tuber, to 40 cm long; sparsely branched; internodes strongly winged towards apex, to 2.5 by 0.6 cm. Lamina obovate; 3 by 1.4 to 6 by 2.5 cm; apex rounded to acute-acuminate, base tapering; midrib prominent below; veins 4–6 on each side; papery in texture; bright green in colour. Petiole 0.3–0.8 cm; stipules blunt, to 0.1 cm, with a central process, caducous. Inflorescence paired, shallow alveoli somewhat paler than surrounding stem, to 0.5 cm across on herbarium specimen (expanding on drying?). Flowers [1]?heterostylous, borne in small cluster at centre of alveolus. Calyx to 1 mm, entire. Corolla tube to 2.5 mm, glabrous within; lobes to 1.5 mm, with a hooked uncus to 0.5 mm. Anthers exserted from tube, to 1.2 mm; pollen 45 µm, pores prominently lipped, brochi 1–1.5 µm. Stigma 2-fid, within mouth of tube. Fruit to 6 by 3 mm, with prominent calyx remains. Pyrenes ovoid, 2.8 by 1.2 mm; apex acute; base rounded.

Ecology & Habitat — Waterlogged riverine forest, Quercus - Castanopsis forest, 550–840 m. Ants not mentioned in collecting notes, but frass in tuber suggests it is ant-inhabited.

Distribution — Indonesia (West Papua Province).

Conservation status — Endangered (EN) under criteria B1ab(iii)+2ab(iii). The two locations are c. 120 km apart. Other information: AOO 385 km 2 (using an auto-value cell width of 12 km), EOO 800 km 2.

Additional specimens examined.Van Royen 6764 (L), Manokwari,Kebar valley, Nettoti, opposite Anjai, 7 Oct. 1961; Ridsdale 2440 (BO, L) S1.14° E132.12°, surroundings of Ayawasi, 2 Apr. 1996.

Notes — The tuber is lobed and reminiscent of the tubers of both H. acuminicalyx [28] and H. multituberosum [23]. Unlike the foregoing, however, it appears to be composed of transverse lobes, which are interconnected by a central element. The surface appearance suggests that the tubers may be partially buried beneath mosses in life, with roots or short spine-like protuberances on the surface. The cavities form a series of transverse chambers, suggesting that the tuber is composed of repeated cavity units. The prominently winged stem and sunken inflorescences are also characteristic to this species and scarcely matched by other species. Hydnophytum tetrapterum [47] was collected at low altitude, and although it possesses similar wings on its stem, the leaves are different. Hydnophytum davisii [19] also from the Kebar valley has a quite distinct tuber, thicker leaves with obscure venation which dry brown, and the corolla has a ring of hairs, and the corolla lobes lack an uncus.