Flora of Thailand
Euphorbiaceae
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Neck. ex A.Juss., Euphorb. Gen.: 27. 1824; (‘Crozophora’), nom. & orth. cons.; Müll.Arg. in DC., Prod. 15, 2: 746. 1866; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vi: 17. 1912; Prain, Bull. Misc. Inform.: 49. 1918; Airy Shaw, Kew Bull. 26: 232. 1972; G.L.Webster, Ann. Missouri Bot. Gard. 81: 73. 1994; Welzen, Blumea 44: 419. 1999; Radcl.-Sm., Gen. Euphorbiacearum: 151. 2001; Welzen in Chayam. & Welzen, Fl. Thailand 8, 1: 156. 2005; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11: 142, Fig. 32. 2014.
Herb or undershrub, monoecious. Indumentum of dense, sessile and pedicelled stellate or lepidote hairs and simple hairs (latter mainly on lower leaf surface). Stipules caducous. Leaves spirally arranged, simple, ovate, often 3-lobed, coriaceous, symmetric, margin shallowly to distinctly laxly crenate, apex rounded, abaxially usually basally with 2 glands near insertion and often with submarginal glands, glands crater-like; venation basally trinerved, secondary nerves ending open in the margin, veins laxly scalariform. Inflorescences terminal racemes, single (or 2 together), not branching, basal flowers pistillate, apical ones staminate; rachis tomentose. Flowers actinomorphic, staminate flowers usually 2 per node, pistillate flowers usually single; calyx 5-lobed, valvate; petals 5; disc indistinct, glabrous. Staminate flowers subsessile; calyx campanulate, lobes ovate; petals slightly larger than sepals, obovate; disc glands separate, united with petals; stamens 13—16, filaments united into a column, branching off in c. 3 layers, anthers basi-dorsifixed, 4-locular; pistillode absent. Pistillate flowers pedicellate; calyx and petals persistent, both 5-merous, narrowly ovate, petals sepaloid in texture, slightly smaller than calyx; disc annular, very flat; pistil 3-locular, on short gynophore, one ovule per locule. Fruits slightly lobed capsules, triangular in transverse section, densely stellate outside, glabrous inside. Seeds covered by a thin, incomplete sarcotesta; latter carunculate on apex.
Eleven species from Africa and the Mediterranean through S.W. and S. Asia to S.W. Asia, probably accidentally introduced in Central Java (Indonesia). One species in Thailand. Classification: Subfam. Acalyphoideae, tribe Chrozophoreae, subtribe Doryxylinae.
Chrozophora rottleri (Geiseler) A.Juss. ex Spreng., Syst. Veg. 3: 850. 1826; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vi: 19. 1912; Prain, Bull. Misc. Inform.: 94. 1918; see for full synonymy; Steenis, Bull. Jard. Bot. Buitenzorg ser. 3, 17: 399. 1948; Nath, Bot. Surv. S. Shan States: 109. 1960; Backer & Bakh.f., Fl. Java 1: 477. 1963; Welzen, Blumea 44: 420, Fig. 2, Map 1. 1999; in Chayam. & Welzen, Fl. Thailand 8, 1: 156, fig. 34. 2005.— Croton rottleri Geiseler, Croton Monogr.: 54. 1807.— Chrozophora plicata (Vahl) A.Juss. ex Spreng. var. rottleri (Geiseler.) Müll.Arg. in DC., Prod. 15, 2: 747. 1866.
Herb to undershrub, up to 60 cm high. Indumentum consisting of stellate and (few) simple hairs. Stipules 1.3—2.7 by c. 0.3 mm. Leaves: petiole 0.8—5.5 cm long; blade ovate, not to usually distinctly 3—lobed, 2.6—9 by 2.6—9 cm, length/width ratio 1—1.9, pale green, base obtuse to usually emarginate, margin without distinct glands, lower surface with 2 glands near the base, 1 mm in diameter, and usually several smaller ones submarginally. Inflorescences up to 4 cm long, elongating in fruit up to 10 cm long. Staminate flowers 4—6 mm in diameter, yellow; calyx white, united part c. 1 mm high, lobes 3.2—4 by c. 1.2 mm; petals 3.7—3.8 by 1.5—1.6 mm; androphore 3.3—3.8 mm long, lower 1.2—1.3 mm without filaments; latter short, 0.3—0.8 mm long; anthers 0.9—1.3 by c. 0.7 mm, yellow. Pistillate flowers 3.2—3.3 mm in diameter, (greenish to) yellow; pedicel 1.4—2 mm long, elongating in fruit up to 1.1 cm; calyx only basally united, lobes 1.5—2.2 by 0.5—0.7 mm; petals 1.3—2 by 0.4—0.6 mm; ovary ovoid, 2.7—3 by 2.2—3 mm wide. Fruits 8—9 by c. 5 mm. Seeds 3.8—3.9 by 3.2—3.6 by 3—3.2 mm.
T h a i l a n d.— NORTH-EASTERN: Phetchabun (Phetchabun); EASTERN: Chaiyaphum (Chaiyaphum); CENTRAL: Chai Nat (Chai Nat), Sing Buri (Inburi), Ang Thong (Ang Thong), Krung Thep Maha Nakhon (Bangkok); SOUTH-EASTERN: Ratchaburi (Ban Pong).
D i s t r i b u t i o n.— India (type?), Myanmar, Thailand, Andaman Islands, and Central Java (Indonesia). The plant has probably been accidentally introduced in Java, because it is only known from an area of a sugar cane factory.
E c o l o g y.— Locally common in wet places like waste areas, along roads, and along and in stream beds; soil: clay (mud), sand. Altitude: 10—200 m.
V e r n a c u l a r.— Ya rakna (หญ้ารักนา) (Chiang Mai); phaya mutton (พญามุติต้น) (Phetchaburi); thua na (ถั่วนา) (Ratchaburi); ma phrao hao (มะพร้าวห้าว) (Central).
U s e s.— The fruits provide a blue-colouring dye, though the plant has never been cultivated for this purpose.