Hydnophytum petiolatum var. contortum, 2019

d. var. contortum (Merr. & L.M.Perry) Jebb & C.R.Huxley View in CoL , stat. nov. — Fig. 13 View Fig ; Map 3 View Map 3

Basionym: Hydnophytum contortum Merr. & L.M.Perry, J. Arnold Arbor. 26 (1945) 17. — Type: Brass 5849 (lectotype selected here A; iso BO, BRI, CAL), Papua New Guinea, Western Province, Wuroi, Oriomo River, Mar. 1934.

Tuber globose, to 30 cm across, surface smooth, grey to brown. Entrance holes of various sizes, 0.1–1 cm across, rounded, large holes lipped. Stems numerous, to 20(–30) by 0.5 cm, branching; internodes angular to rounded, 1–4 by 0.5 cm, nodes to 1.2 cm across, contorted. Leaves subsessile. Lamina elliptic to broad-obovate; 3 by 1.5 to 6 by 4 cm; apex rounded; base tapering, rounded and abruptly attenuate; midrib prominent below, veins 4–6; leathery, brittle; drying brownish red. Petiole 0–0.3 cm; stipules to 0.2 cm, caducous. Inflorescence sessile to sunken, usually with a dense cushion of bract hairs to 1 cm across. Flowers [4] heterostylous. Calyx 1 mm, entire, with attached bract hairs to 1.5 mm long. Corolla tube 8 mm; lobes 3 mm; tube with a broad ring of hairs at mouth. Short-styled flowers with anthers to 1 mm, exserted on 1 mm filaments; pollen 3-porate, 57 (48–60) µm, brochi 2 µm; stigma within mouth of tube. Long-styled flowers with anthers within mouth of tube; pollen 3-porate, 64 (59–66) µm, brochi> 2 µm; stigma immediately above anthers. Fruit ellipsoid, to 8 by 4.5 cm, with prominent hairy calyx remains. Pyrenes obovoid-obtriangular, to 4.5 by 3 cm; apex rounded; base tapering.

Ecology & Habitat — Mangrove forest to lowland forest, sea level to 200 m. Tuber usually inhabited by ants, and then by a range of ant species.

Distribution — Papua New Guinea (Western, Central and Morobe Provinces).

Conservation status — Least Concern (LC). Whilst probably Vulnerable in some parts of its range, this taxon is widespread across much of Papua New Guinea with herbarium collections indicating at least six locations (subpopulations). Other information: georeferenced collections 12, EOO c. 160 000 km 2.

Note — The almost sessile, rounded leaves, short contorted internodes and hairy calyx distinguish this variant. It has a wide distribution in Papua New Guinea.