Hydnophytum orichalcum Jebb & C.R.Huxley, 2019

46. Hydnophytum orichalcum Jebb & C.R.Huxley View in CoL , sp. nov. — Fig. 49 View Fig

Tuber amplum.Caules numerosi,ramosi, quadrati in sectione.Folia sessilia. Lamina lanceolato-cordata, 3.5 per 1.3 ad 5 per 2 (8.5 per 3.5) cm, apice acuto, basi cordata usque obtusa, nervo medio supra et subtus prominente, badia in statu sicco. Inflorescentia binata,pedunculis haud ramosis,ad 2 mm longis. Flores heterostyli. Calyx 1.5 mm, integer. Corollae tubus ad 6 mm, lato annulo pilorum intra faucem instructus; lobi 3 mm. Pyrenae ovoideae, 4 per 2.5 mm,basi rotundata, apice obtuso-acuto, ventraliter complanatae. —

Typus: Brass 28005 (holo A; iso BO, K, L), Papua New Guinea, Milne Bay Province, Sudest Island , Mt Riu , west slopes, 4 Sept. 1956 .

Etymology. From the Greek for brass,derived from oros = mountain and chalkos = copper.

Tuber large. Stems numerous, to 80 by 0.5 cm, branching; erect to subpendent. Internodes 1–5 cm, ± square in section. Leaves scattered, sessile. Lamina lanceolate-cordate, 3.5 by 1.3 to 5 by 2 (8.5 by 3.5) cm; apex acute; base cordate to blunt; midrib prominent above and below, veins 5 or 6; margin recurved when dry; reddish brown in colour when dry. Stipules to 0.2 cm, triangular, papery, caducous. Inflorescence paired, peduncles unbranched, to 0.2 cm long. Bracts minute, <0.1 cm, papery, persistent. Flowers [3], heterostylous. Calyx 1.5 mm, entire. Corolla tube to 6 mm, lobes to 3 mm, a broad ring of hairs within mouth of tube, and partly exserted. Short-styled flowers with anthers 1.3 mm, exserted; pollen 3-colpate, to 58 μm; stigma 2-fid, immediately below anthers. Long-styled flowers with anthers to 1.5 mm; within mouth of tube; pollen 41–45 μm; stigma exserted. Fruit to 6 by 3.5 mm, orange. Pyrenes ovoid, 4 by 2.5 mm; apex blunt-acute; base rounded.

Ecology & Habitat — Low to mid-level epiphyte in forest, 100–500 m. Tuber with or without ants.

Distribution — Papua New Guinea (Milne Bay Province).

Conservation status — Vulnerable (VU) under criteria D2 with only the two island locations known.

Additional specimens examined. Brass 27955 (A, K, L), Louisiade Archipelago, Sudest Island, Mt Riu, W slopes; Brass 28248 (A, L), Rossel Island, Abaleti.

Note — This species has distinctive, apetiolate long-cordate leaves. It differs from H. cordifolium [40] in its sessile or shortly pedunculate (<0.2 cm) inflorescence. Leonard Brass (1900– 1971) was one of the most prolific ant-plant collectors, and it is fitting that we name this species, only ever collected by him, it being unfortunate that the species named in his honour has been reduced to a synonym of H. moseleyanum in this revision.