Hydnophytum petiolatum var. lacum, 2019

e. var. lacum Jebb & C.R.Huxley View in CoL , var. nov. — Map 3

a Hydnophytum petiolatum sed lamina ovata usque obovata, 1.6 per 1 ad 3.8 per 1.9 cm, apice acuto usque brevissime acuminato, basi rotundato usque cuneato, nervi obscurato 4 vel 5. Petiolus ad 1 cm. Stipulae ad 0.3 cm, triangulares, persistentes. Pyrenae obovoideae, 3.2 per 1.7 mm, apice rotundato.

View Map 3

— Typus: Eyma 4851 (holo BO), New Guinea, Papua Province, Enarro valley ,Apr. 1939 .

Etymology. For the characteristic lakes of the type locality.

Tuber irregularly globose; 19 by 15 cm to much larger; often pendulous; surface brown, smooth. Entrance holes of two types: lipped and 1–1.5 cm overall; funnel-like to 4 cm across. Stems several, spreading to erect, to 60 by 0.3–0.7 cm; regularly branched, angular in section, internodes 0.5–6 cm, nodes slightly swollen, grey-brown in colour. Lamina ovate to obovate; 1.6 by 1 to 3.8 by 1.9 cm; apex acute to minutely acuminate; base rounded to cuneate; midrib prominent above and below, veins obscure 4 or 5. Petiole 1 cm; stipules triangular, to 0.3 cm, papery, somewhat persistent. Inflorescence sessile, bract-covered, the bracts leathery to 0.5 cm, with dense reddish brown hairs within. Flowers [2] heterostylous. Calyx to 1 mm, with a margin of septate hairs to 1 mm. Corolla tube to 2.5 mm; lobes 1.5 mm; with a ring of hairs at mouth of tube. Short-styled flowers with anthers to 1.5 mm, exserted from tube; pollen 3-colpate, 49 (48–51) µm, brochi 2–2.5 µm; stigma at level of anthers. Long-styled flowers with anthers within mouth of tube; pollen 3-colpate, 37–42 µm, brochi 1–2 µm; stigma above level of anthers. Fruit ovoid, 6 mm, orange. Pyrenes obovoid, 3.2 by 1.7 mm; apex rounded; base tapering.

Ecology & Habitat — A low-level epiphyte of shady, mossy forest, 400–1770 m. Tuber not inhabited by ants.

Distribution — Indonesia (Papua Province).

Conservation status — Endangered (EN) under criteria B1ab(iii)+2ab(iii). The four locations occur to the north and south of the Weyland Mountain range suggesting it is likely to have a greater distribution. Other information: EOO of 770 km 2 and AOO of 377 km 2 (using an auto-value cell width of 10 km).

Additional specimens examined. Kanehira & Hatusima 12265 (A, BO, FU 2 sheets), Wissel, Dalman, 25 km inland from Nabire; Eyma 4851 (BO), Wissel Lakes,Upper Ennaro Valley and Poeraida ridge, near Enarotali; Eyma 4812 (BO), Eyma 5069 (BO) Wissel Lakes, Cape Weremoeka.

Note — The minute leaves make these collections similar to several high altitude species found in western New Guinea (group 5); however, the swollen nodes with alveoli densely filled with bract hairs, and the rounded leaves which dry glossy yellow below indicate its affinity with the H. petiolatum complex. Named for the Wissel (Paniai) lake region from where it has been collected.