342 



NATAL SPECIES OF THE GENUS CASSIA 



BY 



Helena Forbes, 

 Natal Herbarium, Durban. 



Read July 12, 1921. 



The genus Cassia belongs to the sub-order Caesalpiuiae of 

 the order Leguminoseae. It is essentially a tropical and sub- 

 tropical genus, and is best represented in tropical America. 



The senna leaves of medicine are the leaves of different 

 species which occur principally in Upper Egypt, Syria, India, 

 Arabia and Senegal. The seeds of a few species are edible. In 

 Natal, Cassia occidentalis is used as an ingredient in native 

 antidotes for snake bite, but, apart from this, the Cassias in 

 South Africa are not used medicinally. 



The Cassias flower during the late summer or early autumn, 

 and their masses of golden-yellow blooms, make bright conspicuous 

 patches in the bush and along the roadside. Cassia mimusoides 

 flowers earlier in the year — October to March usually — and is a 

 small, diffuse plant. 



The plants vary from tall woody shrubs to small diffuse herbs. 

 The flowers ai - e perfect, with five slightly perigynous sepals; five 

 yellow, unequal petals; ten stamens, of which seven are fertile, 

 unequal and open by apical pores, and three abortive. The ovary 

 is superior, many seeded and stipulated. The fruit is a linear, 

 terete or compressed, many-seeded legume. 



Key to Species of Cassia. 



Leaves densely tomentose (1) tomentosa. 



Leaves finely tomentose (2) Delagoensis. 



Leaves glabrous. 



Leaflets large, varying from 4 cm. to 10 cm. long. 



Leaflets 3 to 4 pairs, ovate, acuminate (3) laevigata. 



Leaflets 4 to 6 pairs, ovate to lanceolate, reddish tinge 

 on petioles, mid-ribs, etc. (4) occidentalis. 



Leaflets small, not exceeding 4 cms. 



Leaflets 12 to 45 pairs, lanceolate (5) mimosoides. 



Leaflets 4 to 5 pairs, ovate, brown, margin round edge 



of leaflets (6) bicapsularis. 



(1) Cassia tomentosa, Lam. 



A tall shrub with densely pubescent branches and leaves. 

 Leaflets 4 to 6 pairs, oval-oblong, obtuse, tomentose, 2.5 cm. to 

 8 cm. long, 1 cm. to 4 cm. broad; petiole grooved, tomentose, 

 with a gland at the base; stipules about 0.5 cm. long, narrow, 

 pubescent, deciduous; peduncles short, 4 to 6 flowered; sepals 

 unequal, five, two outer light green, hairy, three inner larger, 

 yellowish-green, two glabrous, one slightly hairy; petals unequal, 



