Hydnophytum mayuense Jebb & C.R.Huxley, 2019

32. Hydnophytum mayuense Jebb & C.R.Huxley View in CoL , sp. nov. — Fig. 35 View Fig ; Map 5 View Map 5

Tuber complanatum;superficies laevis,aperturis elevatis.Caules complures, rotundati. Lamina ovata ,3.6 per 2.1 ad 6 per 3.9 cm, apice acuto,basi sensim attenuata. Petiolus 0.7 cm. Inflorescentia sessilis, bracteis obtecta; quae bracteae densae, triangulares, papyraceae, ad 0.8 cm, siccando brunneae, caulem ad nodos fertiles obtegentes. Calyx integer,ad 1 mm. Corollae tubus ad 5.5 mm, lobis 2.5 mm, annulo pilorum ad faucem instructus. Antherae exsertae, 1 mm, filamenta ad 1 mm. Pyrenae obovoideae, 3.5 per 2 mm, apice rotundato, basi angulari cuneatae, tum abrupte truncatus.

— Typus: Stevens in LAE 55653 (holo L; iso A, BRI, CANB, K, LAE), Papua New Guinea, Milne Bay Province, Scarp of Tantam Plateau overlooking Mayu River , 18 July 1972 .

Etymology. For the type locality.

Tuber flattened, to 20 cm across, surface smooth with slightly raised entrance holes. Stems several, spreading, to 40 by 0.5 cm; internodes 1–5 cm. Lamina ovate; 3.6 by 2.1 to 6 by 3.9 cm; apex acute, base tapering; midrib prominent below, less so above; veins 5 or 6; dark shiny green above, pale below. Petiole 0.7 cm; stipules to 0.2 cm, triangular to rounded, caducous. Inflorescence sessile, bract-covered, these dense, triangular, papery to 0.8 cm, drying brown, obscuring stem at fertile nodes. Flowers [1]?heterostylous. Calyx entire, to 1 mm. Corolla tube to 5.5 mm, lobes 2.5 mm; with a ring of hairs at mouth of tube. Anthers to 1 mm; exserted, filament to 1 mm. Stigma missing, but apparently below corolla mouth. Fruit spherical, red, to 5 mm, with prominent calyx remains. Pyrenes obovoid, 3.5 by 2 mm; apex rounded; base angular, cuneate then abruptly truncate.

Ecology & Habitat — Forest, 2 010 m. Occasionally ant-occupied (P. Stevens notes).

Distribution — Papua New Guinea (Morobe, Milne Bay and Northern Provinces).

Conservation status — Vulnerable (VU) under criteria D2 with only two locations known almost 400 km apart.

Additional specimens examined. HÖft 2822 (L) Morobe Province, Mt Kolorong Wildlife Conservation Area, Kuper Range.

Note — Resembles S. vanuatuensis [55], but has petiolate leaves, and more robust bracts.