Hydnophytum hailans Jebb & C.R.Huxley, 2019

31. Hydnophytum hailans Jebb & C.R.Huxley View in CoL , sp. nov. — Fig. 34 View Fig ; Map 5 View Map 5

Tuber irregulariter globosum, superficie laevi. Aperturae dispersae, duo generum, pleraeque labrosae, ad 0.5 cm in diametro, pauciores infundibuliformes, ad 2 cm in diametro. Caules pauci, parce ramosi, quadrangulares. Lamina ovata , 2.1 per 1.6 (1.5 per 1) ad 4 per 3 cm, apice obtuso usque acuto, basi rotundata usque cordata. Petiolus 0–0.2 cm. Inflorescentia sessilis; bracteis obtecta, quae bracteae papyraceae, ad 0.8 cm, triangulares. Calyx 2 mm,margine 4 vel 5 dentato. Corollae tubus 2.5 mm, annulo pilorum ad faucem instructus. Lobi 1.5 mm. Antherae exsertae, ad 1.3 mm. Stigma 2-lobatum, pari libra ad altitudinem antherarum. Pyrenae obovoideae, 3.5 per 2.5 mm,apice rotundato-acuto,basi sensim attenuata.

— Typus: Huxley & Turton in UPNG 5919c (holo LAE; GoogleMaps iso A, GoogleMaps BRI, GoogleMaps CANB, GoogleMaps K, GoogleMaps L, GoogleMaps UPNG), Papua New Guinea, S5°57' E143°51', Southern Highlands Province, foothills of Mt Giluwe on Mendi-Hagen Road GoogleMaps .

Etymology The lingua franca of the Papua New Guinea highlands region is Melanesian Pidgin, and ‘Hailans’ is the pidgin name for that region.

Tuber irregularly globose, to 20 cm diam, surface smooth, brown; roots numerous, short, throughout surface. Entrance holes of two kinds: some prominently rimmed, 0.2–0.5 cm internally; others funnel-like, to 2 cm daim, scattered throughout surface. Cavities 1–7 cm across, largest towards centre of tuber. Tuber tissue buff in colour. Stems few, upcurving, spreading, occasionally branching to 60+ cm; internodes 0.5–4 by 0.2–0.4 cm, 4-angled; nodes swollen. Leaves spreading. Lamina ovate; (1.5 by 1) 2.1 by 1.6 to 4 by 3 cm; apex blunt to acute, base rounded to cordate; mid-green above, pale below; leathery; midrib prominent above and below; veins 5–7. Petiole 0–0.2 cm; stipules to 0.6 cm, rounded to triangular, with a prominent central appendage, persistent. Inflorescence paired, sessile, bract-covered, bracts triangular, to 0.8 cm, papery. Flowers [2]?not heterostylous. Calyx 2 mm, margin 4 or 5 dentate. Corolla tube 2.5 mm, with a ring of hairs at mouth; lobes with a minute crest at tip,1.5 mm.Anthers exserted, 1.3 mm. Pollen 55 (53–57) µm,colporate,brochi <1 µm across.Stigma 2-lobed,at same level as anthers. Fruit ovoid, to 5 mm, with prominent calyx remains; orange-red. Pyrenes obovoid, 3.5 by 2.5 mm; apex rounded-acute; base tapering.

Ecology & Habitat — Forest, 2 000–2 700 m. Tuber not inhabited by ants.

Distribution — Papua New Guinea (Southern Highlands to Morobe).

Conservation status — Vulnerable (VU) under criteria B1ab (iii)+2ab(iii). Two main populations exist, one in the central highlands and one in Morobe Province with a geographical spread of 470 km. Whilst the strict EOO covers some 18 000 km 2, the actual habitat is a fraction of this. Other information: AOO 40 km 2 (2 × 2 km squares) or 14 400 km 2 (using an auto-value cell width of 42 km).

Additional specimens examined. Jebb 597 & 598 ( LAE ), Western Highlands Province, S5°30' E144°12', Jimmi divide,on road from Baiyer River to the Jimmi Valley; Ash in UPNG 3469 (UPNG), Southern Highlands Province, S6°10'E143°57',Onin,SE of MtGiluwe, Ialibu subprovince; Jebb 287, 291 & 292 ( LAE ), SE of Mt Giluwe, on logging track above Onin; Jebb 591 ( LAE ), S6°11' E143°54’, Beechwoods logging track c. 8 km after Onin, S of Mt Giluwe, off Mt Hagen to Mendi road; Jebb 571, 572, 573, 574, 575, 576, 577, 578 & 579 ( LAE ), Morobe Province, Aseki divide, beside road from Bulolo to Aseki; Huxley in UPNG 3453 (UPNG), Wau, near Eddie Creek turning, Mt Kaindi summit road; Jebb 26 ( LAE ), Wau, Mt Kaindi summit road; HÖft 3612 (L, LAE ), Mt Kolorong Wildlife Conservation Area, Kuper Range.

Note — A somewhat nondescript species that can be distinguished by its rounded leaves with prominent midrib above and below that often dries to a pinkish tinge. The tuber is irregular, and the stems are often distorted.