Hydnophytum heterophyllum Merr. & L.M.Perry

Jebb, M. H. P. & Huxley, C. R., 2019, The tuberous epiphytes of the Rubiaceae 7: a revision of the genus Hydnophytum, Blumea 64, pp. 23-91 : 73-74

43. Hydnophytum heterophyllum Merr. & L.M.Perry — Fig. 46

Hydnophytum heterophyllum Merr. & L.M.Perry (1945) 15. — Type: Brass 12857 (A), New Guinea, Papua Province, 6 km southwest of Bernhard Camp, Idenburg River, Feb. 1939.

Tuber small. Spines few, slender, not sharp ± 1 cm. Stems solitary, pendulous to 1 m long, branched towards apex. Internodes terete, 1–4 cm. Leaves strikingly varied in size; larger, ovate and cordate based on the lower stem, smaller and elliptic towards the apex. Lamina 2 by 1.3 to 13 by 7.6 cm; midrib distinct above and below, thick towards base; lateral veins 5 or 6, inconspicuous. Petiole (0.5–)0.7–1 cm; stipules minute, caducous. Inflorescence solitary or paired, shortly pedunculate. Bracts minute. Flowers [1 – bud only]. Calyx membraneous, truncate. Corolla tube with a ring of sparse hairs from midway to mouth of tube; lobes 1.5 mm long. Anthers just within tube, c. 1 mm long. Stigma not known. Fruit to 6 mm, orange. Pyrenes ovate, 4 by 2 mm; apex abruptly shouldered with a prominent apiculum forming a fine point 0.5–1 mm in length, which is contiguous with a prominent abaxial ridge that runs to base of pyrene; base rounded.

Ecology & Habitat — High epiphyte in forest, at 1 200 m.

Distribution — Indonesia (Papua Province).

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

Note — The variable size and shape of the leaves are a striking feature of this specimen. For differences from H. cordifolium [40] see notes for that species.

Figures

Fig.46 Hydnophytum heterophyllum Merr.& L.M.Perry. a. Shoot;b. flower; c. pyrene abaxial face (Brass 12857 (A)). — Scale bars: a = 5 cm; b, c = 5 mm. — Drawn by Rosemary Wise.