Hydnophytum moseleyanum Becc.

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 : 47-49

14. Hydnophytum moseleyanum Becc. — Fig. 17

Hydnophytum moseleyanum Becc. (1884) 125; (1885) 150, t. 35: 10–14; K.Schum.& Lauterb. (1901) 587; (1905) 401; Valeton (1927) 138. — Type: Moseley s.n. (K), Papua New Guinea, Manus Island, Mar. 1875.

Hydnophytum loranthifolium (Benth.) Becc. (1884) 124; (1885) 146, t. 33: 8–13. — Lasiostoma loranthifolium Benth. (1843) 224. — Type: Hinds s.n. (K), Papua New Guinea, 1841, syn. nov.

Hydnophytum oblongum (Benth.) Becc.(1884) 124;(1885) 140,t. 33:1–7. — Lasiostoma oblongum Benth. (1843) 225; Valeton (1927) 139. — Type: Barclay s.n. (K), Papua New Guinea, New Ireland, syn. nov.

Hydnophytum papuanum Becc. (1884) 124;(1885) 147,t. 36. — Type: Beccari PP 186 (lectotype selected here FI; iso K), New Guinea, West Papua Province, Sorong, 20 May 1872, syn. nov.

Hydnophytum crassifolium Becc.(1884) 124;(1885) 148,t. 37:6–12. — Type: Beccari s.n. (lectotype selected here FI; iso K), New Guinea, Maluku Province, Aru Island, Giabu-lengan, syn. nov.

Hydnophytum philippinense Becc. (1884) 125; (1885) 149, t. 33: 14–19. — Type: Moseley s.n. (K), Philippines, Zamboanga, Malanipa Island, Jan.- Feb. 1875, syn. nov.

Hydnophytum moseleyanum var. teysmannii Becc.(1885) 151, t. 35:15–20. — Hydnophytum montanum auct. non Blume: Scheff. (1876) 31 p.p. — Type: Teysmann 7510 (lectotype selected here BO; iso K not seen), New Guinea, Papua Province, Humboldt Bay, syn. nov.

Hydnophytum longistylum Becc.(1885) 152,t.38:1–10;K.Schum.& Lauterb. (1901) 587; Valeton (1927) 136. — Type: Guppy 183 (lectotype selected here K; iso FI), Solomon Islands, Faro Island, syn. nov.

Hydnophytum macrophyllum Warb.(1891) 441. — Type: Warburg 21449 (B presumed lost), Papua New Guinea, syn. nov.

Hydnophytum forbesii Hook.f. (1892) t. 7218; Merr. & L.M.Perry (1945) 15. — Type: Forbes s.n. (K), New Guinea, syn. nov.

Hydnophytum laurifolium Warb. (1894) 209. — Type: Naumann s.n. (B presumed lost), New Guinea, 17 June 1875, syn. nov.

Hydnophytum mindanaense Elmer (1911) 1039,as ‘ mindanaensis’. — Type: Elmer 10974, published as 10874 (lectotype selected here L; iso E, Fl), Philippines, syn. nov.

Hydnophytum agatifolium Valeton (1912b) 774; Merr. & L.M.Perry (1945) 15. — Type: Gjellerup 137 (BO, L), New Guinea, Papua Province, syn. nov.

Hydnophytum robustum Rech. (1912) 186. — Type: Rechinger 3751 (holo W), Papua New Guinea, syn. nov.

Hydnophytum brachycladum Merr. (1915) 142. — Type: Mangubat BS 924 (K, PNH), Philippines, June 1906, syn. nov.

Hydnophytum brassii S.Moore (1927) 271. — Type: Brass 1200 (holo BM not seen; iso A, BRI, K), Papua New Guinea, Gulf Province, Keuru, 23 Mar. 1926, syn. nov.

Hydnophytum camporum S.Moore (1927) 271. — Type: Brass 605 (holo BM not seen; iso A, BRI), Papua New Guinea, Gulf Province, Biriatabu, 11 Nov. 1925, syn. nov.

Hydnophytum capitatum Valeton (1927) 129. — Type: Schlechter 16489 (B presumed lost), Papua New Guinea, syn. nov.

Hydnophytum cuneatum Valeton (1927) 133. — Type: Ledermann 6556 (holo L), Papua New Guinea, Ambunti, syn. nov.

Hydnophytum subfalcifolium Valeton (1927) 141. — Type: Schlechter 14202 (B presumed lost), Papua New Guinea, between Ramu and coast, Feb 1902, syn. nov.

Hydnophytum subrotundum Valeton (1927) 142. — Type: Schlechter 14177 (holo WRSL), Papua New Guinea, between Ramu and coast, Feb 1902, syn. nov.

Hydnophytum stewartii Fosberg (1940) 123; Merr. & L.M.Perry (1945) 18. — Type: Stewart s.n. (A), Solomon Islands, syn. nov.

Tuber globose to bell-shaped, 6 by 5 to 30 by 45 cm; green to silvery-grey in colour, the surface smooth or areolate, occasionally with tubercle-like spines to 0.5 cm in length and 0.2–0.3 cm broad at their base. Entrance holes scattered, of two types: the majority small, lipped or unlipped holes 0.2–0.6 cm across; the remainder larger, funnel-like, 1–3 cm across. Cavities larger and more globose towards centre of tuber, finer, planar and more branched near the surface of the tuber. Cavity walls warted and smooth-walled. Stems numerous, branching, spreading to pendulous; to 1 m in length, 0.5–1.5 cm diam, internodes to 10 cm when sterile, 0.5–4 cm when fertile. Lamina variable in shape, most commonly subrotund-lanceolate, 3.5 by 1.5 to 13 by 7.5 (20 by 6.5) cm, also ranging from narrowly lanceolate (6.5 by 0.5 to 12 by 1.5 cm in H. agatifolium ) to circular (6 by 5 cm in H. brassii ); apex acute to rounded; base blunt; venation obscure; fleshy and leathery. Petiole 0.2–0.3 cm, rarely to 1 cm, pale green to white in colour, and this colouration characteristically extending as a slender triangle to a third or more of the length of the lamina; stipules triangular, papery, to 0.4 cm, caducous. Inflorescence paired, rarely 4 or 6, tubercle-like peduncles, extending with age and bearing flowers at their apex only; to 3 cm long, and 0.4–0.6 cm diam; bracts minute. Flowers [7] heterostylous. Calyx obovoid-cupuliform, somewhat narrowed at margin, to 1.5 mm. Corolla tube 4–7.5 mm, lobes 2.5–4.5 mm, with a broad ring of hairs within the mouth, and usually over lower half of lobes. Short-styled flowers with anthers to 2 mm, exserted; stigma 2-fid, below anthers, within mouth of corolla tube. Long-styled flowers with anthers to 1.5 mm, scarcely within mouth of tube; stigma exserted. Pollen 3-porate, 47 (43–55) μm diam. Fruit globose, to 6 by 5 mm, with prominent calyx remains. Pyrenes oblong-obovoid, 4.5 by 2.5 mm, abaxial surface with a central groove; apex truncate to notched, and with a flattened, filiform or more rarely inflated, central appendage to 2 mm long; base rounded.

Ecology & Habitat — Common in mangrove swamps and other coastal forests, rarely to 400 m. Tuber nearly always inhabited by ants.

Distribution — Philippines, Indonesia (North Maluku, western New Guinea), Papua New Guinea and the Solomon Islands.

Conservation status — Least Concern (LC). Whilst probably Vulnerable in some parts of its range, this taxon is spread across over 5 000 km with herbarium collections indicating over 50 locations (subpopulations). Other information: georeferenced collections 66, EOO c. 4 million km 2.

Notes — This widespread species has characteristically, fleshy, yellowish green leaves, with a short petiole. On drying they remain thick and leathery. The midrib often dries in a characteristic manner, forming a paler or, more rarely, darkercoloured triangular pattern on the upper surface of the leaf. The notched pyrene with an apical appendage is a characteristic but variable feature of this and the closely related species H. grandifolium [13].

The great variation in leaf shape, from the narrowly lozenge-shaped leaves of H. agatifolium to the almost perfectly orbicular leaves of H. brassii has lead to an unnecessary proliferation of names. Valeton (MS at L) intended describing a large number of varieties that were never published.

Some of the foregoing names could be retained as varietal names, however, for the most part it forms a more unified grouping than that of H. petiolatum , and is restricted to coastal forests throughout its range. We had considered retaining a single variety based on H. agatifolium and H. subfalcifolium since these collections do show a correlation of lozenge-shaped leaves, which are frequently falcate also, and a tuber surface with regular short fleshy tubercles. In the end we have decided that such a solitary and somewhat isolated variety provides no benefit to understanding the species as here defined. According to his notes (MS Leiden), Valeton had planned to name the species ‘ H. agathifolium ’ in reference to the leaves resembling those of Agathis spp. ( Araucariaceae ) in shape. The altered spelling in the final publication obscures the intended etymology.

Figures

Fig. 17 Hydnophytum moseleyanum Becc. a. Whole plant; b. flower; c. adaxial; d. lateral; e. abaxial faces of pyrene. f– g. Hydnophytum agatifolium. f. shoot tip; g. pyrene (c–e: Brass 8851 (L), Papua Province, Jautefa Bay; f: Huxley in UPNG 5902; g: Gjellerup 137 (L), Papua Province, Jayapura). — Scale bars: a = 7.5 cm; b = 10 mm; c–e = 5 mm; f = 5 cm; g = 10 mm. — Drawn by: a, b: Eleanor Catherine; c–g: Rosemary Wise.