Hydnophytum cordifolium Valeton

40. Hydnophytum cordifolium Valeton View in CoL — Fig. 43 View Fig

Hydnophytum cordifolium Valeton (1927) 129. — Type: Schlechter 19636 (lectotype selected here K; iso G), Papua New Guinea, Morobe Province, Dischore , 30 May 1909 .

Tuber not known. Stems numerous, to 40 cm, branching, angular, with 4 ridges, grey. Internodes to 4 by 0.3 cm. Lamina ovate to round-cordate, 2 by 1.8 to 6.5 by 4.2; apex blunt to abruptly acuminate; base cordate; leathery to slightly fleshy when fresh, dull dark green above. Midrib impressed above, prominent below, lateral veins 4 or 5. Petiole 0.3–1 cm; stipules triangular, to 0.25 cm, with a central ridge, falling before the leaves. Inflorescence solitary or paired, unbranched, to 0.7 cm long. Bracts minute. Flowers [2]. Calyx truncate. Corolla 4–5.5 mm, lobes 2 mm, ring of hairs either at tube apex, around anthers or midway up tube below anthers. Anthers 1 mm. Pollen 36–42 μm, 3-colporate. Stigma just above anthers, bifid. Fruit not known. Pyrenes ovate to elliptic, rounded on inner adaxial face, strongly ridged on abaxial side, 3–5 by 2.5 mm; apex long or short acuminate; base rounded.

Ecology & Habitat — Forest, sea level to 300 m.

Distribution — Papua New Guinea (Morobe Province).

Conservation status — Endangered (EN) under criteria B1ab (iii)+2ab(iii). The three locations have a geographic spread of 80 km. Other information: EOO 249 km 2, AOO 175 km 2 (using an auto-value cell width of 8 km).

Note — Resembles H. heterophyllum [43], but the leaves are always cordate, less than 6 cm long and the pyrenes lack the characteristic shouldered apex of this latter species. Hydnophytum orichalcum [46] can be distinguished by its longer, sessile leaves, longer flowers and blunt pyrenes. The two specimens differ somewhat in inflorescence number, flower structure and pyrene shape.