Flora of Thailand

Euphorbiaceae

 

61. Micrococca

 

P.C. van Welzen & V.G. Sagun

 

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Genus description

Species description

 

Micrococca

 

Benth. in Hook.f., Niger Fl.: 503. 1849; Mόll.Arg. in DC., Prodr. 15, 2: 789. 1866; Pax in Engl., Pflanzenr. IV.147.vii: 131. 1914; Whitmore, Tree Fl. Malaya 2: 118. 1973; Airy Shaw, Kew Bull. Add. Ser. 4: 5, 20. 1975; Radcl.-Sm., Fl. Trop. E. Afr. (Euphorb. 1): 260. 1987; G.L.Webster, Ann. Missouri Bot. Gard. 81: 88. 1994; Radcl.-Sm., Gen. Euphorbiacearum: 219. 2001; Sagun & Welzen, Blumea 47: 150. 2002; Welzen & Sagun in Welzen & Chayam., Fl. Thailand 8, 2: 448. 2007; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11: 121. 2014.— Claoxylon A.Juss. sect. Micrococca Mόll.Arg., Linnaea 34: 166. 1865.— Mercurialis sect. Erythrante Baill., Ιtude Euphorb.: 490. 1858.

 

Woody herbs or shrubs, monoecious or dioecious, glabrous to hairy. Indumentum simple hairs. Stipules narrowly triangular, early caducous. Leaves alternate, simple; petioles channelled above; blade ovate to obovate, symmetric, papery, base often with 2 glands above, apex acuminate, surfaces glabrous to slightly hairy on midrib; venation pinnate, only midrib prominent beneath, nerves 3–10 pairs looped and closed near margin, veins slightly scalariform, inconspicuous, veinlets reticulate, indistinct. Inflorescences axillary, panicles or usually racemes, with several staminate flowers (of which one flowering at a time) or a single pistillate flower per node; bracts ovate to elliptic. Flowers symmetric; sepals 3 or 4; petals absent. Staminate flowers pedicellate; sepals ovate; disc absent; stamens 3–66, filaments glabrous, anthers basifixed, thecae 2, separate, basally attached to the very short connective, latrorse; pistillode absent. Pistillate flowers: pedicel hairy; calyx basally connate, lobes ovate, hairy outside; disc lobes 3, longer than wide, strap-like, alternating with carpels; ovary 3- or 4-locular, hairy; 1 ovule per locule; style absent, stigmas 3, undivided. Fruits lobed capsules, dehiscing loculicidally and septicidally; wall thin, crustaceous; columella slightly widened apically. Seeds smooth, globose to ellipsoid, without any fleshy layer.

    Thirteen species in Africa, Madagascar, India, northern Australia, and Malesia; one species found once in Thailand. Classification: Subfam. Acalyphoideae, tribe Acalypheae, subtribe Claoxylinae.

 

Micrococca mercurialis (L.) Benth. in Hook.f., Niger Fl.: 503. 1849; Pax in Engl., Pflanzenr. IV.147.vii: 133. 1914; Whitmore, Tree Fl. Malaya 2: 118. 1973; Radcl.-Sm., Fl. Trop. E. Africa (Euphorbiac. 1): 261. 1987; H.M.Burkill, Usef. Pl. West Trop. Afr., 2nd ed., 2: 115. 1994; Sagun & Welzen, Blumea 47: 153, fig. 1a-f. 2002; Welzen & Sagun in Welzen & Chayam., Fl. Thailand 8, 2: 448, Fig. 44. 2007.— Tragia mercurialis L., Sp. Pl.: 980. 1753.— Claoxylon mercurialis (L.) Thwaites, Enum. Pl. Zeyl.: 271. 1861.— Microstachys mercurialis (L.) Dalzell & Gibs., Bombay Fl.: 227. 1861.— Mercurialis alternifolia Lam., Encycl. 4: 120. 1797.

 

           

 

Herbs, 13–34 cm tall, monoecious; flowering stem 2–4 mm in diameter, sparsely hairy. Stipules 0.3–1.75 mm long. Leaves: petioles 5–20 mm long, slightly hairy, with glands at the base; blade ovate to elliptic, 18–53 by 10–26 mm, length/width ratio 1.7–2.5, base attenuate to rounded, with 2 glands above; margin crenate, often with glands and hairs in sinuses; apex acuminate; upper surface glabrous to slightly hairy, lower surface sparsely hairy; nerves c. 5 per side. Inflorescences axillary racemes, 17–70 mm long, peduncle 5–43 mm long; bracts ovate to elliptic, 1–1.75 by 0.3–1 mm, glabrous to sparsely hairy. Staminate flowers 0.5–1.5 mm in diameter; pedicels 0.5–2 mm long, glabrous; sepals ovate, 0.3–1 by 0.3–0.75 mm, glabrous to slightly hairy outside; stamens 3 or 4 (see note), filaments 0.1–0.3 mm long, thecae 0.2–0.4 by 0.1–0.2 mm. Pistillate flowers 1–2 mm in diameter; pedicels 1–15 mm long, hairy; calyx lobes ovate, 1–1.75 by 0.75–0.8 mm, hairy outside; disc lobes 0.5–1 by 0.1–0.25 mm; ovary globose, c. 0.5 mm in diameter, hairy; stigmas 0.2–0.75 mm long, undivided. Fruits 3–5 mm in diameter, glabrous to sparsely hairy, columella 1–2 mm long. Seeds 1.5–2 by 1.5–2 mm in diameter.

    T h a i l a n d.— PENINSULAR: Pattani (Ban Pupo).

    D i s t r i b u t i o n.— Africa to India, Thailand, Malay Peninsula.

    E c o l o g y.— Open sandy places near the coast, open roadsides. Very uncommon in Thailand, introduced. Flowering and fruiting throughout the year.

    U s e s.— Eaten as a vegetable in Gabon. In Congo (Brazzaville) the plant is used to treat children with fever and the plant-sap is instilled into the nose, eyes or ears to treat headache, filariasis of the eye or otitis, respectively (Burkill, 1994).

    N o t e.— African specimens usually have 9 stamens, the Asian specimens 3 or 4.