Hydnophytum mamberamoense Jebb & C.R.Huxley, 2019

45. Hydnophytum mamberamoense Jebb & C.R.Huxley View in CoL , sp. nov. — Fig. 48 View Fig

Myrmecodia species 1 ‘ mamberamoensis ’ C.R.Huxley & Jebb (1993) 332.

Tuber oblongum , laeve. Aperturae 0.2–0.6 cm, labrosae, arcuatim vel seriatim dispositae. Caules complures; internodia fertilia 2–9 cm. Stipulae triangulares, ad 1.6 per 0.6 cm, papyraceae, mox caducae. Lamina ovatoelliptica, 19 per 9 ad 40 per 14 cm, apice acuto, basi cuneato-attenuata, nervis 12–19,coreacea textura.Petiolus 9 cm. Inflorescentia binata,sessilis, obtecta pulvino pilorum bractealium et plurimorum fructuum ineffectorum, omnio ad 3.5 cm in diametro, plus minus contigua, ad instar densae spirae caulem ascenditis; pili bracteales ad 1.3 cm, badii. Calyx 1.5 mm, integer, supra altitudinem disci. Corollae tubus 8 mm, annulo pilorum infra faucem instructus;lobi anguste triangulares,ad 5 mm, unci ad 2.5 mm.Antherae 1.5 mm, ad faucem tubi. Stigma bifidum, supra antheras.Fructus et pyrenae ignota.

— Typus: Docters van Leeuwen 9540 (holo L; iso A, BO, K, SING), New Guinea, Papua Province, Mamberamo river opposite Albatros biv ,July 1926 .

Etymology. For the type locality.

Tuber oblong, 18 by 11 cm; smooth-surfaced. Entrance holes 0.2–0.6 cm, rimmed; often in arcs or lines. Stems several, unbranched? to 50+ by 1.5 cm; internodes 2–9 cm when fertile. Lamina ovate-elliptic; 19 by 9 to 40 by 14 cm; apex acute; base cuneate, ultimately attenuate; veins 12–19; leathery in texture. Petiole 9 cm; stipule intrapetiolar, triangular, to 1.6 by 0.6 cm, papery, soon falling. Inflorescence paired, sessile, covered by a mass of bract hairs, to 3.5 cm across; more or less contiguous, appearing as a thick spiral up stem. Bract hairs to 1.3 cm, reddish brown, with numerous undeveloped fruits. Flowers [1]?heterostylous. Calyx 1.5 mm, entire, above level of disc. Corolla tube 8 mm; with a ring of hairs below level of mouth; lobes narrow-triangular to 5 mm, unci to 2.5 mm. Anthers 1.5 mm, at mouth of tube. Pollen 3- (or 4-)colpate; 100–120 μm; colpi with large swollen borders to 20 μm across; brochi 1–2 μm. Stigma bifid, above anthers. Fruit undeveloped and pyrenes unknown.

Ecology & Habitat — In forest on trees or rockwalls, 100– 175 m. Apparently not inhabited by ants.

Distribution — Indonesia (Papua Province).

Conservation status — Vulnerable (VU) under criteria D2 with only three locations known. These locations are widespread (350 km) along the northern coastal plains of Papua Province.

Additional specimens examined. Kanehira & Hatusima 12293 (FU), Dalman, 45 km Inland from Nabire; Docters van Leeuwen 10134 (A, K, L), S3°00' E138°00', Rouffaer (Tariku) river.

Note — This species has been difficult to place to a genus, chiefly because of its large intrapetiolar stipules, a character otherwise not known in Hydnophytum . The large inflorescences, pollen grains with thick bordered pores, a coarse reticulation, and large petiolate leaves are more like Myrmecodia (as suggested in Huxley & Jebb 1993), however, the tuber lacks the characteristic Myrmecodia -type cavity arrangement (Jebb 1985, 1991a), and the species is placed in Hydnophytum more by default than by diagnosis.