Hydnophytum petiolatum var. nigrescens, 2019

g. var. nigrescens (Merr. & L.M.Perry) Jebb & C.R.Huxley View in CoL , stat. nov. — Map 3 View Map 3

Basionym: Hydnophytum nigrescens Merr. & L.M.Perry, J. Arnold Arbor. 26 (1945) 16. — Type: Brass 7171 (lectotype selected here A; iso BM, BRI), Western Province, Papua New Guinea, Palmer River, 2 miles below junction Black River, ridge forests, July 1936.

Tuber globose. Stems numerous, branching, internodes 1.5–5 by 0.3 cm, nodes swollen; drying black. Leaves strikingly variable in size. Lamina elliptic-obovate, 3.5 by 2 to 8.5 by 4.5 cm, but mostly 4.5 by 2 to 5 by 2.5 cm; apex abruptly acute; base cuneate to attenuate; midrib prominent on both sides; veins 8 or 9. Petiole 0.4–0.7 cm. Inflorescence sunken, with a mass of brown bract hairs; 0.8–1.2 cm across. Flowers [1]?heterostylous. Calyx 1.5 mm, margin irregular, thin, surface furfuraceous. Corolla tube 5 mm; lobes 2 mm; with a ring of hairs at mouth and base of lobes.Anthers 1.3 mm, within mouth of tube; pollen 3-colpate, 54 (51–62) µm, brochi 1 µm; stigma exserted. Fruit unknown. Pyrenes obovoid-oblong, 2.5 by 2 mm; apex truncate, with prominent lateral lobes like short horns, base rounded.

Ecology & Habitat — Canopy epiphyte of ridge forest, 100 m. Tuber not inhabited by ants.

Distribution — Papua New Guinea (Western Province).

Conservation status — Vulnerable (VU) under criteria D2 with only the type specimen known.

Note — This variety is similar to the description of var. ledermannii , differing in its longer petiole and the slightly ‘horned’ pyrenes.