a. var. petiolatum

Hydnophytum petiolatum Becc.

Hydnophytum kochii Valeton.

Tuber globose. Stems numerous, branching, nodes swollen. Lamina elliptic, 6 by 2.5 to 11 by 4 cm; apex rounded-acute; base rounded, abruptly attenuate. Petiole 0.5–2 cm; stipules triangular, to 0.2 cm, caducous. Inflorescence socket-like to somewhat pulvinate cushions of bract hairs, to 1.2 cm across. Flowers [4] heterostylous. Calyx 1.5 mm, entire. Corolla tube to 4 mm; lobes 2 mm; tube with a broad ring of hairs within mouth of tube. Short-styled flowers with anthers to 2 mm, exserted on 1 mm filaments; stigma within mouth of tube. Long-styled flowers with anthers to 1.5 mm, at mouth of tube; stigma exserted. Pollen 3-porate, 57 (54–59) µm, pores and vesicules large, brochi 2–3 µm. Fruit ellipsoid to obovoid, 5 by 4 mm. Pyrenes obovoid, 3.5 by 3 mm; apex and base rounded.

Ecology & Habitat — Mangrove swamp to lowland forest, to 100 m. Tuber inhabited by ants.

Distribution — Indonesia (western New Guinea), Papua New Guinea (Sepik Province).

Conservation status — Least Concern (LC). Known from just five locations but with a geographical spread of 1 300 km this taxon is enigmatic. The figures for AOO and EOO are probably uninformative in view of the sparse numbers. Other information: AOO 10 000 km 2 (using an auto-value cell width of 50 km) and EOO of 135 000 km 2.

Note — The type of H. kochii has somewhat oblong leaves compared to those of H. petiolatum, but in other characters the collections are a close match.