Hydnophytum dentrecastense Jebb & C.R.Huxley, 2019

41. Hydnophytum dentrecastense Jebb & C.R.Huxley View in CoL , sp. nov. — Fig. 44 View Fig

" Tuber parvum . Caules quadrati. Lamina lanceolata ,4 per 1.2 cm ad 6.5 per 2.8 cm, apice acuminato, basi cuneata. Petiolus ad 0.4 cm. Inflorescentia binata,sessilis usque pedunculata,ad 1 cm longa.Calyx ad 1 mm.Corolla ad 3 mm, annulo pilorum ad faucem instructa.Antherae 1 mm longae. Pyrenae ovoideae, 4.5 per 2.5 mm, complanatae.

— Typus: Jebb 387 (holo LAE; iso A, BRI, CANB, K, L), Papua New Guinea, Milne Bay Province, Normanby Island , Mount Bwebwesu , 600 m, 6 June 1983 .

Etymology. For the d’Entrecasteaux islands from where the species was first recognised.

Terrestrial to epiphytic. Tuber relatively small, 15 by 15 cm, irregularly globose. Entrance holes conical, to 1 cm, scattered and prominent. Stems 1 to several, branching, square in section; upright to subpendent, to 60 by 0.15–0.7 cm. Internodes 1–7 cm. Lamina lanceolate, widest at or slightly below middle; 4 by 1.2 to 6.5 by 2.8 cm; apex acuminate to acute; base cuneate; leathery; margins strongly recurved; glaucous-green, and drying darker below. Midrib prominent below, occasionally caniculate above. Veins 7–9. Petiole to 0.4 cm; stipules to 0.25 cm, triangular, caducous. Inflorescence paired, sessile to pedunculate, to 1 cm. Bracts minute, papery. Flowers [2] heterostylous. Calyx to 1 mm, margin entire. Corolla tube to 3 mm; lobes 1.5 mm; a ring of hairs at mouth of tube. Short-styled flowers with anthers to 1 mm long, exserted; pollen 3-colpate, 45 μm, brochi 1 μm; stigma 2-lobed, within mouth of tube. Long-styled flowers with anthers to 0.5 mm; within mouth of tube; pollen 54 μm; stigma exserted. Fruit to 6 mm, conical-ovoid, red. Pyrenes ovoid, 4.5 by 2.5 mm; flattened; apex blunt-acute, base rounded.

Ecology & Habitat — This species is found terrestrially on the upper slopes of Mts Pabinama and Bwebwesu of Normanby Island, at c. 600–800 m altitude. This is an area of ultrabasic soils with sparse, stunted forest cover.The tuber is not inhabited by ants and nor does it collect rainwater.

Distribution — Papua New Guinea (Milne Bay and Northern Province).

Conservation status — Vulnerable (VU) under criteria D2. The habitat on Normanby Island is an area of ultramafic soils identified as a source of future nickel and gold mining. The entire area covers less than 20 km 2, but it is not known whether this epiphyte is found further afield on that island. Two other localities are on islands and one in Northern Province, a range of over 700 km. Other information:AOO 20 km 2 (using a cell width of 2 km), EOO c. 32 900 km 2.

Additional specimens examined. Woods 350 (E), Northern Province, ridge above Doma; Brass 25682 (A, L), Brass 25698 (A, L), Brass 25786 (A, L), Brass 25789 (A, L), Milne Bay Province; Croft NGF 71018 ( LAE , L), Fergusson Island,E slopes of Mt Kilkerran, Normanby Island,Mt Pabinama; Jebb 380 ( LAE ), Jebb 388 (BRI), Jebb 389 ( LAE ), Jebb 390 ( LAE ), Normanby Island, west slopes of Mt Bwebwesu; Brass 28403 (A, BO, K, L), Rossel Island, South slopes of Mt Rossel.

Note — The fresh leaves of this species have a glaucous-green look, and dry to a grey-green colour, darker below.