Blachia
Baill., nom. cons.
Shrubs or trees, monoecious, evergreen, mostly entirely glabrous. Leaves alternate,
simple or rarely lobed, penninerved or sometimes weakly to clearly trinerved at base, shortpetioled;
stipules inconspicuous. Male inflorescences terminal, cymose, umbellate to racemiform,
few-flowered, peduncled; flowers ebracteate; pedicels slender; sepals 4 or 5, free, imbricate;
petals 4 or 5, smaller than the sepals, hyaline; disc glands 4 or 5, alternating with petals, scalelike;
stamens 10 - 40, free, arranged in whorls on raised receptacle; anthers 2-loculed; locules
adnate to a broad connective, free at base, coherent at tip; pistillode absent. Female
inflorescences axillary and terminal, often borne at or near the base of male inflorescences,
cymose, mostly umbellate (2 - 8-flowered), sometimes solitary, shortly peduncled; flowers
ebracteate; pedicels stout; sepals 4 - 6, same as in the male, but shortly connate and accrescent
in fruit or deciduous (B. andamanica); petals absent; disc glands connate in a ring or occasionally
shortly cupular; ovary 3 - 5-loculed; locules uniovulate; ovules anatropous; styles 3 - 5, erect to
reflexed, bifid. Fruits schizocarpic, 3 - 5-lobed; seeds trigonous with a broad convex back,
smooth, marbled.
India, Sri Lanka, Bangladesh, Myanmar, Thailand, Indo-china to Malesia, ca 10 species; 3 species in India.
Literature. BALAKRISHNAN, N. P. & T. CHAKRABARTY (1989). Genus Blachia Baill. (Euphorbiaceae) in India. Proc. Indian Acad. Sci. (Pl. Sci.) 99: 567 - 578, ff. 1 - 4.
Notes. The chromosome number reported so far is for one species only, B. calycina having 2n = 36 by Krishnappa & Reshme (Taxon 29: 536. 1980). Pollination is anemophilous. Pollen grains conform to the typical ‘Crotonoid’ pattern (Punt, Wentia 7: 1 - 116. 1972). The species occurs mostly at low elevations up to 900 m, in evergreen forests but may also grow in semi-evergreen or mixed forests or even in beach forests (B. andamanica).
India, Sri Lanka, Bangladesh, Myanmar, Thailand, Indo-china to Malesia, ca 10 species; 3 species in India.
Literature. BALAKRISHNAN, N. P. & T. CHAKRABARTY (1989). Genus Blachia Baill. (Euphorbiaceae) in India. Proc. Indian Acad. Sci. (Pl. Sci.) 99: 567 - 578, ff. 1 - 4.
Notes. The chromosome number reported so far is for one species only, B. calycina having 2n = 36 by Krishnappa & Reshme (Taxon 29: 536. 1980). Pollination is anemophilous. Pollen grains conform to the typical ‘Crotonoid’ pattern (Punt, Wentia 7: 1 - 116. 1972). The species occurs mostly at low elevations up to 900 m, in evergreen forests but may also grow in semi-evergreen or mixed forests or even in beach forests (B. andamanica).
KEY TO THE SPECIES
| 1 a. Female sepals deciduous; leaves often weakly to clearly trinerved at base; the first pair of lateral nerves distinct, not weaker than subsequent pairs; tertiary nerves predominantly scalariform to reticulate | 1. Blachia andamanica |
| b. Female sepals persistent or accrescent; leaves penninerved; the first pair of lateral nerves nor distinct, weaker than subsequent pairs; tertiary nerves predominantly branching into veins of higher order | 2 |
| 2 a. Female sepals 5 - 15 x 2.5 - 9 mm; fruits 4 - 5-coccous | 2. Blachia calycina |
| b. Female sepals 2 - 5 x 1 - 3 mm; fruits tricoccous | 3. Blachia umbellata |
