Hydnophytum petiolatum var. auridemens, 2019

c. var. auridemens Jebb & C.R.Huxley View in CoL , var. nov. — Fig. 12 View Fig ; Map 3

a Hydnophytum petiolatum sed tuber cum aperturae numerosae, labrosae, 0.3 ad 0.9 cm in diametro. Lamina obovata usque ovata, 6 per 3 ad 7.5 per 4 cm, apice obtusa acuta, basi sensim attenuata, nervi 6 vel 7. Petiolus ad 0.7 cm. Pyrenae obovoideae, 4 per 2 mm, apice rotundato, basi cuneata. —

View Map 3

Typus: Jebb 397 (holo K; iso L, LAE), Papua New Guinea, Milne Bay Province, Misima Island , Mt Sisa , 11 June 1983 .

Etymology. Latin for gold-madness,for the human obsession with seeking gold.

Tuber globose, flattened, to 30 by 20 cm, light brown. Entrance holes numerous, lipped, from 0.3–0.9 cm across (internal); arranged in linear to curved arrays. Stems numerous, branching, to 60 cm long; internodes 1.5–8 by 0.2–0.8 cm, rounded, with 4 fine ridges; young stems ferruginous. Leaves spreading. Lamina obovate to ovate; 6 by 3 to 7.5 by 4 cm; apex blunt-acute, base tapering; leathery, brittle, dark glossy green above, pale below; midrib prominent above and below, and distinct to very apex, veins 6 or 7. Petiole 0.7 cm; stipules 0.2–0.3 cm, triangular, papery, caducous. Inflorescence sunken, with a dense cushion of bract hairs 0.3–0.5 cm in length, forming a mass 1–1.5 cm across. Flowers [4] heterostylous. Calyx 1.5 mm, densely clothed with bract hairs, and with a margin of hairs persistent in fruit. Corolla tube to 5 mm; lobes rounded-triangular, to 3 mm; with a ring of hairs within and exserted from mouth of tube. Short-styled flowers with anthers to 2 mm, exserted; pollen 44 µm diam; stigma below anthers. Long-styled flowers with anthers 1.5 mm, within tube; pollen 37 µm diam; stigma exserted. Fruit 6 mm, ovoid, orange-red. Pyrenes obovoid, 4 by 2 mm; apex rounded; base tapered, notched.

Ecology & Habitat — High to middle-level epiphyte in open forest, 300–400 m. Tuber inhabited by ants.

Distribution — Papua New Guinea (Misima Island).

Conservation status — Vulnerable (VU) under criteria D2 with a single population known from Misima island, the site of a major gold lode and potential mine site. The entire island is under 200 km 2 in extent and less than 50 % of that area remains forested.

Additional specimens examined.Brass 27390 (A, L), S slopes of Mt Sisa, 1956; Jebb 395 (BRI), Jebb 396 (CANB, LAE ), Jebb 398 (A, LAE ), Louisiade Archipelago,Misima Island,S10°39'E152°48',NE slopes of Mt Sisa,11 June 1983.

Note — The pulvinate cushions of bract hairs and the thinner leaves are characteristic of this variety. It is named for the gold rush currently taking place on the island, which has removed almost the entire forest cover from Mount Sisa, and which will probably exterminate much of the endemic flora.