Senna siamea

Senna siamea (Lam.) H. S. Irwin & Barneby, Mem. New York Bot. Gard. 35: 98. 1982; Fl. China @ eFloras.org 10: 29; S. sumatrana Roxb., Hort. Beng. 31.1814; Moon, Cat. 33.1824; DC., Prodr. 2: 506.1825; Cassia siamea Lam., Encycl. Meth. 1: 648. 1785; Baker in Hook. f., Fl. Brit. Ind. 2: 264. 1879; Ali & Qurashi, S. U. Sci. Res. J. 3: 5. 1967; Parker, For. Fl. Punj. ed.1:175.1918 (Reprint 1973); Rudd. in Dassanayake & Fosberg (eds.), A Revised Handbook to the Flora of Ceylon. Vol. 7.1991; Saldanha & Nicolson, Fl. Hassan 221. 1976.

Trees, 10-15 (-30) m tall. Bark grey, sub smooth, young branches ribbed, sparsely puberulent. Leaves alternate, 20-30 cm. long, unipinnately paripinnate; petiole ca. 4 cm long with base pulvinate. Leaflets 6-16 pairs, oblong, elliptic-oblong or ovate-oblong, 3-7 cm x 1.5-2.5 cm, leathery, base rounded, apex obtusely rounded, often emarginate, mucronate; abaxially finely pubescent, glaucous, adaxially glabrous, smooth. Stipules small, 1-2 mm long, linear, caducous. Rachis and petiole without glands, with adaxial groove, puberulent. Flowers in long terminal panicle of corymbs, corymbs solitary or in pairs, peduncles of panicle and corymbs, 2.5-7 cm long; bracts linear, 5-6 mm long, curved, dilated at the middle; pedicels up to 3.5 cm long. Flowers zygomorphic, bisexual, pentamerous, perigynous, ca. 1.2-1.7 cm across. Sepals suborbicular, unequal in size, outer smaller, inner larger, ca. 9 mm, greenish-yellow, hairy outside. Petals dull yellow, broadly obovate, elliptic or orbicular, 1.2-1.5 cm, shortly clawed. Stamens 10, 7 fertile, anthers dehiscing by apical pores, 2 with filaments ca. 10 mm and anthers 6-7 mm, 4 or 5 with filaments 2-4 mm and anthers 5-6 mm; 3 small staminodes, about 3 mm long. Ovary sessile, densely white pubescent, unilocular with many ovules, placentation marginal; style short; stigma subapical, oblique facing downwards. Legumes linear, compressed, nearly straight with apical beak, coriaceous, 15-30 cm x 1-2 cm, sutures thick, rib-like, pubescent, purplish-brown when mature. Seeds 10-30, light brown, ovoid, 6.5-8 mm x 5.5-6 mm, glossy, with an areole on each face.

Flowering and Fruiting: November-March
Common Names: Siamese Senna, Siamese Cassia; Seemi, Kassod (Hindi)