Flora of Thailand Euphorbiaceae

 

66. Ostodes

 

K. Phattarahirankanok & K. Chayamarit

 

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Genus description

Species description

Blume, Bijdr.: 619. 1825; Benth. in Benth. & Hook.f., Gen. Pl. 3: 299. 1880; Hook.f., Fl. Brit. Ind. 5: 400. 1887; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.iii: 17. 1911; Gagnep. in Lecomte, Fl. Indo-Chine 5: 322. 1925; Airy Shaw, Kew Bull. 20: 409. 1967; Kew Bull. 26: 311. 1972; Kew Bull. 36: 334. 1981; G.L.Webster, Ann. Missouri Bot. Gard. 81: 105. 1994; Radcl.-Sm., Gen. Euphorbiacearum: 296. 2001; Phattar. & Chayam. in Welzen & Chayam., Fl. Thailand 8, 2: 460. 2007; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11: 173. 2014.

Shrubs or trees, dioecious or monoecious; latex absent or reddish. Indumentum simple. Stipules caducous. Leaves alternate, simple, crowded at the tips of the branches, symmetric; petiole with 2 apical glands; margin crenate or serrate, tips glandular; triplinerved. Inflorescences axillary to pseudo-terminal, thyrsoid, panicles when staminate, racemes to single-flowered when pistillate, pedunculate. Flowers pedicellate, calyx 5-lobed, imbricate; petals 5(6), free, longer than calyx. Staminate flower: calyx lobes unequal; disc-glands 5(6), free, oppositisepalous; stamens 16–40, outer filaments shortly connate at base or ± free, inner more connate, villous at base; anthers subdorsifixed, introrsely longitudinally dehiscent; pistillode absent; receptacle pilose. Pistillate flower: disc annular; ovary 3-locular, ovules 1 per locule; styles 3, bifid apically; staminodes absent. Fruit 3-lobed to subglobose, apiculate, 6-ribbed, somewhat tardily loculicidally or septicidally dehiscent; endocarp bony; columella slender, splitting longitudinally into 3 strands, subpersistent; calyx not accrescent. Seeds ecarunculate.

    A monotypic tropical Asiatic genus from East Himalaya to South China, SE Asia and Java. In Thailand with two varieties. Classification: Subfamily Crotonoideae, tribe Codiaeae.

Ostodes paniculata Blume, Bijdr.: 620. 1825; Müll.Arg. in DC., Prodr. 15, 2: 1115. 1864; Kurz, Fl. Burm. 2: 404. 1877; Hook.f., Fl. Brit. Ind. 5: 400. 1887; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.iii: 20. 1911; Gagnep. in Lecomte, Fl. Indo-Chine 5: 322. 1925; Backer & Bakh.f., Fl. Java 1: 493. 1963; Airy Shaw, Kew Bull. 20: 411. 1966; Kew Bull. 26: 311. 1972; Phattar. & Chayam. in Welzen & Chayam., Fl. Thailand 8, 2: 461, Plate XXIII: 3. 2007.— Ostodes corniculata Zoll. & Mor. ex Baill., Étude. Gén. Euphorb.: 391. 1858.— Ostodes kerrii Craib, Bull. Misc. Inf. Kew: 464. 1911; Bull. Misc. Inf. Kew: 191. 1912; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vi: 126. 1912; Airy Shaw, Kew Bull. 20: 411. 1966.— Ostodes prainii Gandog., Bull. Soc. Bot. France 66: 287. 1920.

Small trees, 5–15 m high; outer bark rather smooth, grey, lenticellate; inner bark whitish-yellow, with reddish sap. Leaves: petiole 3.5–20 cm long; blade ovate to elliptic, 10–24 by 5–12 cm, coriaceous, glabrous, base obtuse, apex acute to acuminate; nerves in 8 or 9(10) pairs, veins reticulate. Inflorescences 8–13 cm long, glabrous (or slightly pubescent). Staminate flower 3–10 mm in diam., with scent, pendulous; pedicel 0.3–1.5 cm long; calyx lobes oblong, 4–5 by 2–2.5 mm, pale green; petals 6–7 by 2–4 mm, whitish. Pistillate flower 18–20 mm in diam.; calyx lobes oblong, 5–8 mm long, greenish; petals ovate, c. 10 by 7 mm, whitish at base, pinkish at apex, outer ones glabrous, inner ones pubescent at base; ovary glabrous, rarely pubescent, c. 2 mm in diam.; styles 2–3 mm long. Infructescences 5–20(–25) cm long; peduncles 1.5–3(–5) cm long. Fruits 2.5–3.3 cm in diam., exocarp glabrous or slightly pubescent. Seeds ovoid, 1–1.5 cm in diam.

Key to the varieties

1a.	Inflorescences and ovary glabrous or slightly pubescent; stamens 16–35	a. var. paniculata
1b.	Inflorescences and ovary dense pubescent; stamens more than 35	b. var. katharinae

 

a. var. paniculata: Phattar. & Chayam. in Welzen & Chayam., Fl. Thailand 8, 2: 461, Fig. 49. 2007.

 

                           

 

Leaves: usually ovate to elliptic, apex acute to acuminate. Inflorescences usually glabrous to rarely pubescent. Staminate flowers 3–10 mm in diam., stamens 16–35. Pistillate flowers: ovary glabrous, rarely pubescent; styles 2–3 mm long. Fruits 2.5–3.3 cm in diam., exocarp glabrous or slightly pubescent.

    T h a i l a n d.— NORTHERN: Chiang Mai, Chiang Rai, Nan (Doi Phu Kha), Lampang (Chae Son), Tak (Doi Musoe); SOUTH-WESTERN: Kanchanaburi (Dong Yai); NORTH-EASTERN: Loei (Phu Luang); EASTERN: Chantaburi (Soi Dao).

    D i s t r i b u t i o n.— Eastern Himalaya, India, Burma, Southern China, Indochina, Malay Peninsula, Sumatra, Java (type).

    E c o l o g y.— Evergreen forest. Altitude: 400–1400 m. Flowering: December-March; fruiting: January-April.

    V e r n a c u l a r.— Ma khang dong (มะคังดง)(Chiang Mai).

    U s e s.— In Bhutan gum is extracted from the wood and used for paper-making; the leaves are used as cattle fodder.

 

b. var. katharinae (Pax) Chakrab. & N.P.Balakr., Bull. Bot. Surv. India 27: 260. 1987; Phattar. & Chayam. in Welzen & Chayam., Fl. Thailand 8, 2: 463. 2007.— Ostodes katharinae Pax in Pax & K.Hoffm. In Engl., Pflanzenr. IV.147.iii: 19. 1911; Airy Shaw, Kew Bull. 20: 411. 1966; Kew Bull. 26: 311. 1972; Yong-Tian, Acta Phytotax. Sin. 20: 224. 1982.

 

Leaves: some broadly ovate, apex acute or obtuse. Inflorescences densely pubescent. Staminate flowers 5–12 mm in diam.; stamens 36–40. Pistillate flowers: ovary densely pubescent; styles 3–6 mm long. Fruits 3–3.3 cm in diam., exocarp pubescent.

    T h a i l a n d.— NORTHERN: Chiang Mai (Doi Inthanon), Mae Hong Son (Doi Chang).

    D i s t r i b u t i o n.— Eastern Himalaya, India, Southern China (Yunnan, type), Indochina, Malay Peninsula, Sumatra, Borneo, Java.

 

 

    E c o l o g y.— In lower montane forest. Altitude: 1200–2000 m. Flowering: January-April; fruiting: March-October.

    N o t e.— The epithet was originally published as katharinae and not katherinae as in Chakrabarty & Balakrishnan, 1987.