Hydnophytum davisii Jebb & C.R.Huxley, 2019

19. Hydnophytum davisii Jebb & C.R.Huxley View in CoL , sp. nov. — Fig. 22 View Fig

Tuber oblatum,ad 30 per 20 cm;superficies laevis, cum plurumque aperturis 1 ad 1.3 cm latis et 1 ad 1.5 cm altis, cum mura tenuis. Caules numerosi, ramosi, ex stirpe communi enati, ad 1 m longi; internodia terete. Lamina obovata ,2 per 1 ad 4.5 per 1.9 cm, apice rotundato basim sensim attenuata; nervi obscuram; petiolus 0.1 ad 0.2 cm; stipula ad 0.1 cm, caduca. Inflorescentia binata, sessilis, obtecta pulvino pilorum bractealium ad 1 cm in diametro,pili bracteales ad 0.5 cm. Corollae tubus ad 3.5 mm,annulo pilorum ad faucem instructus, lobi 2.8 mm longis.Antherae 1.3 mm, ad faucem exsertae. Stigma bifidum, 2.5 mm. Fructus et pyrenae ignota.

— Typus: Davis & Mayar 800 (holo K; iso BO, L, MAN), New Guinea, West Papua Province, Kebar valley , 7 May 1995 .

Etymology. Named in honour of Aaron Davis of Kew, collector of the type specimen and Rubiaceae expert.

Tuber globose, to 30 by 20 cm across; surface smooth, dark brown. Entrance holes throughout, conspicuous, abrupt cylinders 1–1.3 cm across and 1–1.5 cm tall, with thin walls 0.1–0.3 cm thick. Cavities globose, 0.8–4 cm across, all smooth-walled. Stems several, to 1 m long, branched; internodes 1.7–7 by 0.2–0.6 cm, rounded, ultimate internodes furfuraceous. Lamina obovate; 2 by 1 to 4.5 by 1.9 cm; apex rounded, base tapering, ultimately attenuate; midrib prominent below; veins obscured; lathery; pale brown when dry; margin recurved. Petiole 0.1–0.2 cm; stipules triangular, 0.1 cm, caducous. Inflorescence paired, sessile, covered by cushions of bract hairs to 1 cm across. Bract hairs pale brown, to 0.5 cm long. Flowers [1]?heterostylous, iridescent white. Calyx 0.5 mm entire, with adherent bract hairs. Corolla tube 3.5 mm, with a broad ring of hairs at mouth of tube, and exserted to 1 mm long; lobes 2.8 by 1.5, without an uncus, with many raphides. Stamens exserted, filaments 1 mm, anthers 1.3 mm. Style 2.5 mm long; stigma 2-lobed, lobes c. 0.7 mm, immediately below anthers. Fruit and pyrenes unknown.

Ecology & Habitat — Stunted ridge top Nothofagus forest, at 1 740 m. Tuber not inhabited by ants.

Distribution — Indonesia (West Papua Province).

Conservation status — Vulnerable (VU) under criteria D2 with only the type specimen known.

Note — The tuber is remarkable for the many cylindrical entrance holes. These are taller and thinner-walled than those of H. reevii [34], and are far more numerous and disposed on a quite dissimilar shaped tuber than H. caminiferum [17]. The collector noted an iridescent quality to the flowers, the corolla of which is rich in raphides.