Flora of Thailand
Euphorbiaceae
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Hook.f., Hook. Icon. Pl. 16: Pl. 1587. 1887; Fl. Brit. Ind. 5: 456. 1887; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.xi: 118, f. 28. 1919; Airy Shaw, Kew Bull. 16: 358. 1963; Kew Bull. 21: 406. 1968; Whitmore, Tree. Fl. Mal. 2: 104. 1973; Nguyen Ngia Thin, Biol. J. Hanoi 8: 36. 1986; Welzen, Blumea 43: 141. 1998; Radcl.-Sm., Gen. Euphorbiacearum: 237. 2001; Welzen & S.E.C.Sierra, Blumea 50: 275—277. 2005; Welzen in Welzen & Chayam., Fl. Thailand 8, 2: 351. 2007; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11: 129. 2014.
Shrubs to trees, presumably monoecious. Indumentum (in Thailand) of simple hairs. Stipules triangular, early caducous. Leaves subopposite to in whorls, simple; petiole short, completely pulvinate; blade chartaceous, symmetric, base narrowly cordate, margin entire, with submarginally near base small black-dotted glands above, apex obtusely cuspidate, usually green when dry, paler below, nerves looped and joined near margin, veins scalariform, quaternary veins more reticulate. Inflorescences: staminate flowers in solitary axillary racemes, one flower per node; pistillate flowers single in axils. Flowers actinomorphic, petals and disc absent. Staminate flowers shortly pedicelled; sepals 3; stamens more than 100, united into 4–7 dichotomously branching groups; pistillode absent. Pistillate flowers on long pedicels; sepals 5, leaf-like, reflexed in fruit; ovary 3-locular, one ovule per locule, tuberculate with on top of tubercles a stinging hair; style absent, stigmas 3, not split. Fruits lobed capsules, outside tuberculate, puberulous, septicidally breaking into 3 bivalved parts. Seeds ± obovoid, without arilloid.
Five rare species, one in the Himalayas, another from India to N. Vietnam, touching N. Thailand, two from Vietnam and one spread very disjunctly over Malesia. Classification: Subfam. Acalyphoideae, tribe Acalypheae, subtribe Lasiococcinae.
Lasiococca comberi Haines, Bull. Misc. Inf. Kew: 70. 1920; Kiu, Acta Phytotax. Sinica 20: 108, fig. 1. 1982; Welzen in Welzen & Chayam., Fl. Thailand 8, 2: 351, Fig. 13. 2007.— Euonymus auriculatus Craib (Celastraceae), Bull. Misc. Inf. Kew: 170. 1922.
Trees, up to 10 m high. Stipules c. 3 mm long. Leaves: petiole 3–6 mm long, hairy; blade elliptic to obovate, 9–20 by 4.5–6.5 cm, length/width ratio 2–3.1, venation distinct on both sides, nerves 10–13 per side, domatia absent. Staminate inflorescences pubescent, up to 6 cm long. Staminate flowers: pedicel 3–5 mm long; sepals elliptic to obovate, up to 7 mm long. Pistillate flowers: pedicel 2–4 cm long, pubescent; sepals obovate, 5–6.5 by 1.7–2.3 mm; style c. 2 mm long, stigmas c. 4 mm long. Fruits trilobed, 1.2–1.3 cm in diameter. Seeds not seen.
T h a i l a n d.— NORTHERN: Chiang Mai (Mae Ta); NORTH-EASTERN: Loei (Wang Saphung).
D i s t r i b u t i o n.— India (type) to China, N. Thailand (type of E. auriculatus: Mae Ta, Payap, KERR 3620, holo in K, iso in ABD) and N. Vietnam.
E c o l o g y.— Evergreen forest. Altitude: 300 m.
N o t e.— The differences between Lasiococca comberi and L. malaccensis Airy Shaw from Malesia are slight, L. comberi has broader tubercles on the fruit, a hairy inflorescence (glabrous in L. malaccensis), and lacks hair tuft domatia on the lower leaf surface.