Senna alata

Author: (Linnaeus) Roxburgh

Morphological description
Shrub 1-2(-5) m; branches thick, pubescent (alata Senna compl 428845 ). Stipules auriculate-deltoid, 6-10(-15) mm, persistent, brownish-red.

Leaves paripinnate with 8-20 pairs of leaflets (alata Senna lfl FT27 ); petiole robust, 2-3 cm; rachis 30-60 cm. Leaflets oblong-elliptic, 5-15 by 3-7 cm, obtuse at both ends, glabrous.

Inflorescence: (alata Senna infl 386524; alata Senna infl/pods 139548). Racemes axillary, dense, robust, many-flowered, 20-50 by 3-4 cm; peduncle stout, 7-14 cm; bracts strobilate, at first enveloping the flowers, broadly ovate, caducous, 2-3 by 1-2 cm; bracteoles absent;pedicels 5-10 mm.

Flowers (alata Senna fl 428844 )Sepals 5, orange-yellow, oblong, unequal, 10-20 by 6-7 mm. Petals 5, bright yellow, ovate-orbicular, 16-24 by 10-15 mm, short-clawed. Stamens: 2 large with stout filaments, 4 mm long and anthers 12-13 mm opening with apical pores; 4 with filaments 2 mm long and anthers 4-5 mm opening by apical pores; reduced stamens 3 or 4; filaments of all stamens straight. Ovary puberulous, pruinose, sessile, ovules many (up to c. 58); style filiform; stigma small.

Pods sharply tetragonal, winged, glabrous, black, 10-15 by 1.5-2 cm, wings 4-8 mm (alata Senna infl/pods 139548; alata Senna pod FT27).

Seeds up to c. 50, shining, flattened, quadrangular, 7-8 by 5-8 mm.

According to Irwin & Barneby (1982: 460) native in the Guianas and perhaps in the Orinoco and Amazonean districts of Venezuela; now pantropical. In Java fully established by the middle of the 17th century.

Along riverbanks, rain forest edges, lake shores, margins of ponds and ditches, in open forests and wet areas, in orchards and around villages, often in large populations. It occurs from the lowlands up to 2100 m in New Guinea; it is, however, most abundant below 500 m. On Sumbawa between 200-400 m on dry limestone soil in small groves in the low savanna forest.

Cultivated for medicine and ornament throughout the Malesian area. It is regarded a highly effective remedy against ringworm and various skin diseases; it is also used as a laxative. See Heyne (1950: 740); Burkill (1935: 473); Quisumbing (1951: 377).

According to Verdcourt (1979: 38) it is sometimes becoming a troublesome weed in pastures since the livestock will not eat it and a rapid spread can reduce the area available for grazing.