Trigonostemon viridissimus (Kurz) Airy Shaw

Yu, R. - Y. & Welzen, P. C. van, 2018, A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia, Blumea 62 (3), pp. 179-229 : 221

32. Trigonostemon viridissimus (Kurz) Airy Shaw — Map 14

Trigonostemon viridissimus (Kurz) Airy Shaw (1971) 545; Whitmore (1973) 135; Airy Shaw (1975) 205; (1981) 358; (1982) 36; (1983b) 48; R.I. Milne (1995a) 28,in key, 29,in key. — Sabia viridissima Kurz (1872) 304; Hook.f. (1876) 3; Kurz (1877a) 301. — Blachia viridissima (Kurz) King (1896) 455, in obs. — Kurziodendron viridissimum (Kurz) N.P.Balakr. (1966) 68, pl. 1, f. 1-7. — Type: Kurz s. n. (K, barcodes K000246871, K000246872), India, Andamans.

Trigonostemon ovatifolius J.J.Sm. (1910) 583; Backer & Bakh. f. (1963) 495. — Type: Koorders s. n. (BO?, not seen), Java.

Trigonostemon membranaceus Pax & K.Hoffm.(1911) 91. — Type: Koorders 32989 (BO), Java: Djapara .

Trigonostemon sumatranus Pax & K.Hoffm. (1911) 90; S. Moore (1925) 100 (as synonym of T. forbesii Pax = Wetria insignis (Steud.) Airy Shaw ); Merr. (1935) 101; Jabl. (1963) 163 (see note under T. philippinensis ); W.L. Stern (1967) 671; Whitmore (1973) 135. — Type: Forbes 2647 (BM, K, L), Sumatra.

Trigonostemon macgregorii Merr. (1920) 566; (1923) 452. — Type: BS ( McGregor ) 32424 (holo PNH †; iso K, P, US), Philippines, Panay, Antique Province, Culasi .

Neotrigonostemon diversifolius Pax & K.Hoffm. (1928) 385; (1931) 169. — Type: Parker 2593 ( K), Burma, Mergui , Ngawun Reserve .

Shrubs or small trees, up to 9 m tall, stem up to 10 cm diam; flowering branches 1.5–3 mm diam, sometimes hollow. Bark c. 0.3 mm thick, young parts pale and pubescent, sometimes with numerous oil-like spots, mature parts dark, brownish to greyish, glabrescent; wood pale yellowish. Stipules subulate to nipple-like, c. 0.5 mm long, caducous, often pubescent. Leaves: petiole terete but grooved above, 0.5–1.5(–5.5) cm long, wrinkled, pubescent; blade ovate to elliptic to oblong, sometimes lanceolate, 8–24 by 2.5–9 cm, membranous or chartaceous, often with numerous oil-like spots when young,

Map 14 Distribution of Trigonostemon viridissimus (Kurz) Airy Shaw var. viridissimus (●) and T. viridissimus var. elegantissimus (Airy Shaw) Airy Shaw (★).

base acute or obtuse, often with 1 or 2 pairs of adaxial glands, margin entire or slightly distantly serrate, apex acuminate to caudate, upper side glabrescent to glabrous, dark green, lower side often sparsely pubescent, paler and dull green; venations triplinerved, midrib and 2 basal nerves slightly raised above and well elevated beneath, often pubescent, especially near base, other nerves 6 –10 pairs, bow-shaped and connected along margin, veins scalariform, veinlets reticulate. Inflorescences bisexual (but mostly unisexual), often axillary, loose paniculate, often with oil-like spots on young parts; main rachis terete, up to 25 cm long, c. 2 mm diam, slightly pubescent; branches slender and glabrescent; bracts lanceolate, up to 2 mm long, pubescent. Staminate flowers 5–9 mm diam; pedicel up to 9 mm long, c. 0.2 mm diam, glabrescent or slightly pubescent, often with numerous oil-like spots; sepals elliptic or orbicular, 1–1.5 by 0.6–1.2 mm, imbricate, margin somewhat undulate, apex rounded or truncate, often with a short notch, outer surface pubescent, often with numerous oil-like spots and a gland in the middle; petals obovate, 4–6.5(–10) by 3.5–4.5(–7) mm, contort, membranous, with several distinct parallel veins, base cuneate or somewhat claw-like, apex rounded, glabrous; disc annular, margin undulate, reflexed, sometimes with 5 notches; stamens 3, androphore 0.7–1.5 mm long, filaments 0.3–0.4(–0.6) mm long, anthers free, ellipsoid, 0.4–0.5 mm long. Pistillate flowers 5–9 mm diam, pedicel slightly thickened towards apex, 1–1.4 cm long, apically c. 0.5 mm diam when flowering, elongating up to 3 cm long and c. 1.4 mm diam in fruit, glabrescent, often with oil-like spots; sepals, petals and disc as staminate flowers, except petals caducous when fruiting; ovary 0.8–1 mm diam, glabrous, with numerous oil-like spots on surface, styles 0.2–0.6 mm long, stigmas 0.6–1.5 mm long, bent, slightly thickened and slightly bifid at apex. Fruits c. 1.5 cm diam, greenish, glabrous and with numerous oil-like spots, sepals persistent but not accrescent; wall c. 0.5 mm thick, exocarp detaching; columella c. 5 mm long. Seeds 7–8 mm diam, with numerous oil-like spots on surface; hilum rhombic, c. 1.5 by 1.2 mm.

Distribution — China, India, Thailand, Laos, Vietnam, Malay Peninsula, Sumatra, Java, Borneo, Philippines, Lesser Sunda Islands.

Habitat & Ecology — Primary to secondary forests, along coasts to hillsides, sometimes along rivers.

Note — In addition to the Malesian region, this species is also found in China, India, Thailand, Laos and Vietnam under different names, all synonyms except viridissimus , which is the oldest and accepted epithet for this species.

Key to the varieties

1. Petioles often shorter than 1.5 cm, pubescent. Inflorescences axillary, pendulous, often pubescent.. a. var. viridissimus