Flora of Thailand
Euphorbiaceae
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Miq., Fl. Ned. Ind., Suppl.: 444. 1861; Steenis, Blumea 12: 362. 1964; Airy Shaw, Kew Bull. 25: 506. 1971; Kew Bull. 29: 303. 1974; Kew Bull. 35: 597. 1980; G.L.Webster, Ann. Miss. Bot. Gard. 81: 57. 1994; Radcl.-Sm., Gen. Euphorbiacearum: 90. 2001; S.S.Larsen in Chayam. & Welzen, Fl. Thailand 8, 1: 105. 2005; Welzen & P.I.Forst., Nordic J. Bot. 28 (2010) 189; in Noot., Fl. Males. ser. 1, 20:48. 2011; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11: 99. 2014.— Buraeavia Baill., Adansonia 11: 83. 1873. — Choriophyllum Benth.; Hook. Icon. Pl. 13: t. 1280. 1879.
Shrubs and trees up to 40 m, dioecious. Indumentum simple hairs. Stipules present or absent. Leaves opposite, simple, margin entire, penninerved. Inflorescences axillary, short cymes. Flowers: sepals 4(5 or 6), in two whorls, imbricate; petals and disc (Thailand) absent. Staminate flowers with 4 (Thailand) episepalous, free stamens; pistillode conical. Pistillate flowers: sepals ovate, not accrescent; ovary 2-5-locular, smooth; 2 ovules per locule; style short; stigmas thick, short, persistent. Fruits obovoid capsules, higher than wide, dehiscing into 3 bivalved cocci; columella persistent. Seeds 1–3, smooth, shiny, carunculate (Thailand).
Twenty species from Malay Peninsula to N and NE Australia and Pacific islands. In Thailand one species. Classification: Subfam. Oldfieldioideae, tribe Claetieae, subtribe Dissilariinae.
N o t e.— The two recent major classifications by Webster (1994) and Radcliffe-Smith (2001) separate the genera Austrobuxus and Longetia (monotypic on New Caledonia), this view is followed here.
Austrobuxus nitidus Miq., Fl. Ind. Bat., Suppl.: 445. 1861; Whitmore, Gard. Bull. Sing. 26: 51. 1973; Tree Flora of Malaya 2: 63. 1973; S.S.Larsen in Chayam. & Welzen, Fl. Thailand 8, 1: 105, fig. 23, plate I: 2; Welzen & P.I.Forst., Nordic J. Bot. 28: 190, Fig. 2, 3. 2010; in Noot., Fl. Males. ser. 1, 20: 51, fig. 2; Map 1. 2011. — Choriophyllum malayanum Benth., Hook. Icon. Pl. 13: t. 1280. 1879; Hook.f., Fl. Brit. Ind. 5: 344. 1887.— Longetia malayana (Benth.) Pax & K.Hoffm. in Engl., Pflanzenr. 81: 291. 1922; Ridl. Fl. Mal. Pen. 3: 224. 1924.— Longetia nitida (Miq.) Steenis, Blumea 12: 362. 1964.
Small to medium sized tree up to 30 m with buttresses to c. 2 m. Stipules narrowly oblong, thick, slightly falcate 3–4 by c. 1.5 mm. Leaves: petiole stout, 4–8(–10) mm long; blade elliptic to narrowly obovate, 6–9(–12) by 2–3.5(–6) cm, glabrous, coriaceous, base attenuate, apex rounded, occasionally emarginate, upper side shiny; midrib prominent, reddish when dry, nerves fine, numerous. Flowers tiny in clustered cymes joined in short panicles; peduncles up to 3 cm long, thick when pistillate, axis hairy to puberulous; inflorescence bracts triangular, c. 2.5 mm long hairy; bracts to the flowers broadly triangular, 1–1.5 mm long, bracteoles minute. Staminate flowers on up to 2 cm long peduncles; pedicels 4–6 mm long, sparsely hairy; sepals 4(–5), obovate, c. 2 mm long, reflexed, glabrous; filaments 2–3 mm long, anthers c. 0.5 mm long; pistillode brown hairy. Pistillate flowers: pedicel c. 2 mm long, thick; sepals 2+2, broadly triangular, subequal, 1.5–2 mm long, densely brown hairy, fleshy; ovary ellipsoid-ovate, 3–4 mm long, densely brown hairy, 2-locular; stigma subsessile, 2-lobed. Fruits obovoid, 10–14 by 8–10 mm with 2 bivaled cocci, purplish-green, finely verrucose, drying brown; epicarp thin, separating from the thickly crustaceous cocci; column T-shaped, slender, 10–13 mm long, brownish. Seeds c. 7 by 4 mm, black when dry, caruncle laciniate.
T h a i l a n d.— PENINSULAR: Narathiwat.
D i s t r i b u t i o n.— Throughout Malay Peninsula, Sumatra (type), Borneo.
E c o l o g y.— In evergreen rainforest at low altitude.
N o t e s.— 1. Whitmore l.c., recognizes 3 varieties var. nitidus, var. macrocarpus Airy Shaw (with twice as long fruits) and var. montanus (Ridl.) Whitm. (Syn.: Choriophyllum montanum Ridl.) with smaller, retuse, very leathery leaves. The Thai specimens belong to var. nitidus.
2. In previous descriptions the ovary is generally described as 3-locular. The specimens seen from Thailand (one collection), and few from Malaysia have all a 2-locular ovary.