Hydnophytum dauloense Jebb & C.R.Huxley, 2019

29. Hydnophytum dauloense Jebb & C.R.Huxley View in CoL , sp. nov. — Fig. 32 View Fig ; Map 5 View Map 5

Tuber irregulariter globosum.Aperturae duo generum, vel grandes infundibuliformes vel parvae et conicae. Caules numerosi,ex stirpe communi enati, libere ramosi. Lamina lanceolata ,latissima infra medium, 2.2 per 0.9 ad 7 per 3 cm; apex longe accuminatus, ultimo rotundatus; basis abrupte angustata. Petiolus 1–5 mm. Inflorescentia sessilis, binata. Calyx ad 1.5 mm, margine integro. Corolla alba vel flavida apice dilute viridi; tubus ad 5 mm, basi ventricosus, angustatus ad faucem, qua annulo pilorum ornatus est; lobi ad 2.5 mm.Antherae exsertae,<1 mm. Stigma multifidum, pari libra ad altitudinem antherarum. Pyrenae hemisphericae, ad 3 per 1.6 mm, apice acuto, basi rotundata.

— Typus: Jebb 338 (holo LAE; iso A, BRI, CANB, K, L), Papua New Guinea, Chimbu Province, Mt Elimbari , 14 May 1983 .

Etymology. After the Daulo Pass, where the species is common.

Tuber irregularly globose with rounded lobes; to 30 by 25 cm. Entrance holes of two kinds, large and funnel-like or small and conical. Flesh white, firm. Cavity walls unwarted. Stems numerous; to 100 by 0.3–0.6 cm; arising from a common stock; branching freely, ascending to upcurved. Internodes to 10 cm or more when sterile, 0.3–3 cm when fertile, with 2 prominent, rounded ridges running from below stipule. Leaves loosely clustered. Lamina lanceolate, widest below middle; 2.2 by 0.9 to 7 by 3 cm; apex long acuminate, ultimately rounded; base abruptly attenuate; midrib prominent; glossy dark green above pale below, drying grey /purplish /brown; margin recurved, strongly so when dry. Petioles 0.1–0.5 cm; stipules triangular, white, to 0.4 cm. Inflorescence sessile, paired. Flowers [3]?not heterostylous. Calyx to 1.5 mm above level of disc; margin entire. Corolla white or yellowish with a faintly green tip. Corolla tube to 5 mm, ventricose at base, narrowing to mouth, and with a ring of hairs there; lobes to 2.5 mm, uncus <1 mm, fully reflexed in open flower. Anthers exserted, <1 mm, filaments to 1 mm, closely appressed to one another. Pollen 51–60 μm, walls 2.5–3 μm thick, brochi 1 μm, pores 15–18 μm, vesicles small. Stigma multi-fid, at level of anthers. Fruit ovoid to 5 by 3 mm, red. Pyrenes to 3 by 1.6 mm, more or less hemispherical; apex acute; base rounded.

Ecology & Habitat — Low to high-level epiphyte in montane forest, 2 400–2 800 m. Tuber not inhabited by ants, but collecting rainwater and occupied by a range of invertebrates including cockroaches, centipedes, spiders and on Mt Elimbari the arboreal frog Cophixalus riparius .

Distribution — Papua New Guinea (Eastern Highlands and Chimbu Province).

Conservation status — Endangered (EN) under criteria B1ab(iii)+2ab(iii). The five known localities occurring in one of the most densely populated regions of the Papua New Guinea highlands. Whilst the strict EOO covers some 340 km 2, the actual remaining habitat is a fraction of this. Other information: AOO 28 km 2 (2 × 2 (using a cell width of 2 km)), using an auto-value grid size is likely to be erroneous given the restricted habitat area.

Additional specimens examined. Kerenga & Baker LAE 56924 (K,L, LAE ), Eastern Highlands,S5°90'E144°05', NE of Kamus village; Grubb & Edwards 206 (CGE, L, LAE ), S6°00' E145°11', near (W of) Fatima river, Marafunga Sawmill, Goroka subdistrict; Cruttwell s.n. 1980 ( LAE ), S6°00' E145°25', Mt Gahavisuka National Park, c. 10 km NW of Goroka; C.R.Huxley & Worthing UPNG 3457 (UPNG) S6°02' E145°13', Daulo Pass, Goroka side; Philipson 3529 (L), summit of Daulo Pass; Cruttwell in UPNG 5945 (× 3), Daulo Pass; Pullen 457 (A, CANB, L), S6°03' E145°13', Asaro-Mairifutica divide, S of Daulo Camp; Jebb 333 (A, BISH, K, L), Jebb 334 (BRI, CANB), Jebb 335 ( LAE ), Jebb 336 ( LAE ), Jebb 337 (L, SUVA), Jebb 339 (BRI, CANB, K, L, LAE ), Jebb 340 (A, L, LAE ), Chimbu Province, S6°11' E145°09', NE side of Mt Elimbari, 2 km S of pass on road from Nambaiyufa to Chuave.

Note — This species has a characteristic ovate leaf that is broadest below the middle and tapers to a slender, ultimately rounded, acuminate apex. The leaves approach those of H. terrestris [35], which is distinguished by its large bracts and distinct tuber anatomy.