Malesian Euphorbiaceae Descriptions

72. MICROCOCCA (Euphorbiaceae)

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

Sagun, V.G. & P.C. van Welzen. 2002. Revision of the Malesian species of Micrococca (Euphorbiaceae). Blumea 47: 149–155.

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Genus description

Key to the species

Species descriptions

Micrococca Benth.

    Micrococca Benth. in Hook.f., Niger Fl. (1849) 503; Baill., Étude Euphorb. (1858) 436; Müll.Arg. in DC., Prodr. 15, 2 (1866) 789; Benth. & Hook.f., Gen. Pl. 3(1883) 309; Engl., Pflanzenw. Ost-Afrikas (1895) 238; Prain, Ann. Bot. (London) 25 (1911) 628; Prain in Dyer, Fl. Trop. Afr. 6 (1913) 876; Pax in Engl., Pflanzenr. IV.147.vii (1914) 131; Gamble, Fl. Madras 2 (1925) 1327; Dyer, Flora Capensis 5 (1925) 460; Pax & K.Hoffm. in Engl. & Harms, Nat. Pflanzenfam, ed. 2, 19c (1931) 112; Robyns, Fl. Spermatoph. Parc Nation. Albert (1948) 458; Hutch., Fl. W. Trop. Afr. 1 (1958) 402; Whitmore, Tree Fl. Malaya 2 (1973) 118; Airy Shaw, Kew Bull. Add. Ser. 4 (1975) 5, 20; R.A.Dyer, Gen. S. Afr. F. Pl. 1 (1975) 315; Radcl.-Sm., Fl. Trop. E. Afr. 1 (1987) 260; G.L.Webster, Ann. Missouri Bot. Gard. 81 (1994) 88; Radcl.-Sm., Gen. Euphorbiacearum (2001) 219; Sagun & Welzen, Blumea 47 (2002) 150; Welzen & Sagun in Welzen & Chayam., Fl. Thailand 8, 2 (2007) 448; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11 (2014) 121. — Claoxylon A.Juss. sect. Micrococca Müll.Arg., Linnaea 34 (1865) 166 — Type: Micrococca mercurialis (L.) Benth.

    Mercurialis sect. Erythrante Baill., Étude Euphorb. (1858) 490. — Type: Mercurialis alternernifolia Lam. [= Micrococca mercurialis (L.) Benth.]

Herbs or shrubs; erect, monoecious or dioecious. Indumentum of simple hairs only. Stem terete, glabrous to hairy. Stipules hairy or glabrous, early caducous, narrowly triangular. Leaves simple, alternate, or sometimes the lowermost leaves opposite; peti­oles adaxially channelled, glabrous to slightly hairy; blade ovate to obovate, symmetric, papery, base often with 2 glands adaxially; margin entire or crenate (often with glands and hairs in the sinuses) or denticulate (then often with glands apically on teeth); apex acuminate; adaxial surface glabrous to slightly hairy, abaxial surface glabrous to sparse­ly hairy on midrib; venation pinnate, only midrib prominent abaxially, secondary nerves 3–10 per leaf half, 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) and a single pistillate flower per node, internodes 5–20 mm long; bracts ovate to elliptic, glabrous to sparsely hairy. Flowers unisexual, actinomorphic; sepals 3 or 4; petals absent. Staminate flowers: pedicels glabrous to slightly hairy; sepals ovate, glabrous to slightly hairy outside; disc absent; stamens 3–66, filaments glabrous, anthers basifixed, thecae 2, separate, basally attached to the very short connective, opening latrorsely with longitudinal slits; 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, globular, covered with hairs; 1 ovule per locule; style absent, stigmas 3, undivided, smooth or papillate adaxially. Fruits lobed capsules, glabrous to sparsely hairy, dehiscing loculicidally and septicidally; wall thin, crustaceous; columella slightly widened apically. Seeds smooth, globose to ellipsoid, glabrous.

    Distribution — 13 species in Africa, Madagascar, India, northern Australia, and Malesia (3 spp. in Peninsular Malaysia only).

Key to the species

1. Micrococca johorica Airy Shaw

    Micrococca johorica Airy Shaw, Kew Bull., 25 (1971) 525; Whitmore, Tree Fl. Malaya 2 (1973) 118; Sagun & Welzen, Blumea 47 (2002) 151, fig. 1g, h. — Type: KEP FRI (Whitmore) 160 (holo SING), Malaysia, Johore, State Land, 13 km S of Labis Forest Reserve.

Shrub, c. 1 m tall, dioecious; fruiting branches 3–5 mm in diameter, hairy. Stipules c. 0.75 mm long. Leaves: petioles 3–47 mm long, glabrous to hairy; blade narrowly obovate, 11–25.5 by 2.2–7.7 cm, length/width ratio 3.3–5, base acute, with 2 glands above; margin laxly denticulate, often with glands apically on teeth; apex acuminate; adaxial surface glabrous, abaxial surface with sparse hairs only on midrib and veins; nerves 7–19 per side. Inflorescences axillary racemes or panicles, 7–12.5 cm long, peduncle 1–2 cm long, internodes 5–6 mm long, bracts ovate to elliptic, 0.75–3 by 0.3–1.5 mm, glabrous to sparsely hairy. Staminate flowers c. 1.5 mm in diameter; pedicels 2–4 mm long, glabrous to sparsely hairy; sepals ovate, 1.5–1.75 by 1.25–1.5 mm, hairy outside; stamens 54–66, filaments 0.3–0.4 mm long, thecae 0.25–0.3 by c. 0.2 mm. Pistillate flowers not seen. Fruits 5–7 by 10–13 mm, glabrous. Seed c. 5 by 5 mm.

    Distribution — Malaysia: Johore State: Kluang Forest Reserve; Sungai Sedili, below Mawai.

    Habitat & Ecology — Flowering from February to April; fruiting in July.

2. Micrococca malaccensis Airy Shaw

    Micrococca malaccensis Airy Shaw, Kew Bull., 25 (1971) 524; Whitmore, Tree Fl. Malaya 2 (1973) 118; Sagun & Welzen, Blumea 47 (2002) 151, fig. 1i-k. ---Type: SF (Kiah) 37230 (holo SING), Malacca: Batang Malaka Forest Reserve.

Shrub, c. 3 m tall, dioecious; flowering branches 2–5 mm in diameter, hairy. Stipules c. 1 mm long. Leaves: petioles 5–10 by 1.5–2 mm, hairy; blade elliptic to narrowly obovate, 12.4–17.2 by 5–5.7 cm, length/width ratio 2.5–3; base rounded to acute, glands absent; margin laxly denticulate, often with glands apically on teeth, usually involute; apex acuminate; adaxial surface glabrous, abaxial surface hairy only on midrib and veins; nerves 8–10 per side. Staminate inflorescence axillary panicles, 9–16 cm long; pe­duncle 22–50 mm long, internodes 1–2 cm long, bracts ovate, c. 0.75 by 0.75 mm, hairy outside. Staminate flowers c. 2 mm in diameter; pedicels 1–2 mm long; sepals ovate to elliptic, 1–1.75 by 0.5–1 mm, hairy outside; stamens 18–40, filaments 0.4–0.5 mm long, thecae c. 0.25 by 0.25 mm, 2-lobed, connective V-shaped. Pistillate flowers and fruits not seen.

    Distribution — Malaysia: Malacca (Batang Malaka), NW Johore (Ulu Segamat).

    Habitat & Ecology — Altitude c. 300 m. Flowering from April to September.

3. Micrococca mercurialis (L.) Benth.

    Micrococca mercurialis (L.) Benth. in Hook.f., Niger Fl. (1849) 503; Trimen, Syst. Cat. Fl. Pl. Ceylon (1885) 82; Engl., Planzenw. Ost-Afrikas (1895) 238; De Wild., Ann. Mus. Congo Belge, ser. 2 Bot., 1.1 (1899) 50; De Wild., Ann. Mus. Congo Belge, ser. 2 Bot, 1.2 (1900) 57; Prain, Ann. Bot. (London) 25 (1911) 631; Prain in Dyer, Fl. Trop. Afr. 6 (1913) 876; Pax in Engl., Pflanzenr. IV.147.vii (1914) 133; A.Chev., Explor. Bot. Afrique Occ. Franc. (1920) 576; Gamble, Fl. Madras 2 (1925) 1328; Robyns, Fl. Spermatoph. Parc Nation. Albert (1948) 458; Whitmore, Tree Fl. Malaya 2 (1973) 118; Almeida, J. Bombay Nat. Hist. Soc. 82 (1985) 238; Radcl.-Sm., Fl. Trop. E. Africa (Euphorbiac. 1) (1987) 261; H.M.Burkill, Usef. Pl. West Trop. Afr., 2nd ed., 2 (1994) 115; Sagun & Welzen, Blumea 47 (2002) 153, fig. 1a-f; Welzen & Sagun in Welzen & Chayam., Fl. Thailand 8, 2 (2007) 448, Fig. 44. — Tragia mercurialis L., Sp. Pl. (1753) 980; Sp. Pl. (1763) 1391; Willd., Sp. Pl. IV (1805) 324; Moon, Cat. Pl. Ceylon (1824) 62; Roxb., Fl. Ind. 3 (1824) 576; J.Graham, Cat. Pl. Bombay (1839) 186; Prain, Bengal Pl. 2 (1963) 710. — Claoxylon mercurialis (L.) Thwaites, Enum. Pl. Zeyl. (1861) 271; Müll.Arg. in DC., Prodr. 15, 2 (1866) 790; Hook.f., Fl. Brit. India 5 (1890) 412; Trimen, Handb. Fl. Ceylon 4 (1898) 63; J. Bombay Nat. Hist. Soc. 12 (1899) 372; Hiern, Cat. Afr. Pl. 1 (1900) 976; T.Cooke, Fl. Bombay 2 (1908) 609; T.Durand, Syll. Fl. Congol. (1909) 492; Prain, Bengal Pl. 2 (1963) 710; Vartak, Enum. Pl. Gomantak India (1966) 94. — Microstachys mercurialis (L.) Dalz. & Gibs. Bombay Fl. (1861) 227. — Lectotype (designated by Radcliffe-Smith, 1987): Plukenet, Phytographia (1696), 248, t.205/4.

    Mercurialis alternifolia Lam., Encycl. 4 (1797) 120, Baill., Adansonia 1 (1860) 76, 125, 279. — Type: Adanson s.n. (P-JU), Senegal.

Herb, 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; adaxial surface glabrous to slightly hairy, abaxial surface sparsely hairy; nerves c. 5 per side. Inflorescences axillary racemes, 17–70 mm long, peduncle 5–43 mm long, internodes 5–13 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, smooth or papillate. Fruits 3–5 mm in diameter, glabrous to sparsely hairy, columella 1–2 mm long. Seed 1.5–2 by 1.5–2 mm in diameter.

    Distribution — Africa to India, Peninsular Thailand (Trang); Malesia: Malaysia (Penang, Perak, Trengganu) and Singapore.

    Habitat & Ecology — Open sandy places near the coast. Uncommon. Flowering and fruiting throughout the year.

    Uses — 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).

    Note — African specimens usually have 9 stamens, the Asian specimens 3 or 4.