Hydnophytum petiolatum Becc.

11. Hydnophytum petiolatum Becc. View in CoL — Fig. 12 View Fig , 13 View Fig ; Map 3 View Map 3

Hydnophytum petiolatum Becc. (1884) 124; (1885) 144, t. 34. — Type: Beccari PP 187 (lectotype selected here FI; iso K), Sorong, West Papua Province , 1872.

Hydnophytum kochii Valeton (1911) 507. — Type: Koch 26 (lectotype selected here L; iso BO), West Papua Province, Fakfak, 23 Nov. 1904, syn. nov.

Hydnophytum ledermannii Valeton (1927) 134. — Type: Ledermann 12925 (B presumed lost), Papua New Guinea, Sepik River, syn. nov.

Hydnophytum nigrescens Merr.& L.M.Perry (1945) 16. — Type: Brass 7171 (lectotype selected here A; iso BM, BRI), Papua New Guinea, Western Province, Palmer River, 2 miles below junction Black River, ridge forests, July 1936, syn. nov.

Hydnophytum contortum Merr. & L.M.Perry (1945) 17. — Type: Brass 5849 (lectotype selected here A;iso BO,BRI,CAL),Papua New Guinea,Western Province, Wuroi, Oriomo River, Mar. 1934, syn. nov.

Tuber globose, to 50 cm across; surface smooth, brown to grey to silvery. Entrance holes of various sizes, 0.1–1 cm across, rounded, lipped. Cavities warted and smooth-walled. Stems numerous, branching, sometimes zigzagged; nodes swollen, especially when fertile. Lamina lanceolate to cordate-ovate; 2 by 1.2 to 11 by 5 cm; apex rounded to acute, base cordate to cuneate; midrib prominent below, or more rarely prominent on both sides; leathery, often drying a reddish brown colour. Petiole 0–2 cm; stipules triangular or blunt, to 0.5 cm, persistent becoming part of inflorescence margin. Inflorescence paired, sunken, cup-like, with a mass of reddish bract hairs, sometimes with numerous papery bract remains; 0.4–1.5 cm across. Flowers heterostylous. Calyx 1–2 mm, entire or with a fringe of brown hairs. Corolla tube 2–6 mm, lobes 2–5 mm, tube with a broad ring of hairs at mouth and base of lobes. Anthers 1–2 mm long, exserted or within mouth of tube. Pollen 36–60 µm, brochi 0.5–2.5 µm across; characteristic of many of the individual varieties are the irregular vesicles, with one often larger than the remaining two. Stigma above or below anthers. Fruit obovoid, 3–6 mm, with prominent calyx remains, orange to red. Pyrenes obovoid, 2.5 by 1.5–4 by 2.5 mm; apex rounded to truncate, sometimes 3-lobed; base tapering, blunt.

Ecology & Habitat — Mangrove forest or coastal trees to forest, open or disturbed areas, including forest on nutrient-poor soils, sea level to 1 800 m. Tubers sometimes inhabited by ants, sometimes not.

Notes — This taxon has not been satisfactorily resolved, however, it seems to us that the lumping of these five species is the most reasonable step to take with our current knowledge. Rather than obscure the variation, seven geographic varieties are recognised, three of which are illustrated. The chorology of leaf and pyrene shapes are presented on Map 3 View Map 3 .All these varieties share the following features: stems contorted, zigzagged at nodes; leaves leathery or fleshy, drying a characteristic reddish brown colour; inflorescences socket-like, and usually filled with dense, reddish brown bract hairs, which become more prominent on dried specimens; calyx with hairs strongly attached to its outer surface, and sometimes to its margin.

Distribution — Indonesia (western New Guinea) and Papua New Guinea. Individual variants are distributed as follows: Variant Distribution

11a. var. petiolatum New Guinea.

11b. var. argentatum Normanby Is. , PNG.

11c. var. auridemens Misima Is , PNG.

11d. var. contortum Western, Central, Morobe, PNG.

11e. var. lacum Wissel lakes, West Papua Province. 11f. var. ledermannii Sepik, PNG.

11g. var. nigrescens Western, PNG.