Citation: L., Sp. Pl. 376 (1753).

Derivation: Greco-Latin word, from the Hebrew qase'ah, used to denote a sort of cinnamon bark and also some fragrant shrub.

Synonymy: Not Applicable

Common name: None

Description:
Shrubs rarely small trees; tomentum of simple or curled hairs; leaves paripinnate or in several species reduced to phyllodes; 1 or more glands often present on the petiole; stipules usually small and caducous.

Flowers in racemes which are sometimes reduced and subumbellate; petals slightly irregular, about the same size, yellow, often showy; anthers 10 or some reduced to staminodes, opening by apical pores; ovary incurved, with several ovules; stigma small.

Pod 2-valved, flat or turgid, divided by more or less transverse septa; seeds compressed, transverse or oblique, obovate; funicle short, slender.

Distribution:  Pan-tropic genus of many species.

Biology: Several authors (for example Irwin & Barneby in Polhill & Raven (1981) Advances in legume systematics 1:105) consider that the majority of species previously placed in Cassia, including most Australian species, should be transferred to Senna Miller. Were this done there would be about 30 species in Cassia worldwide and about 240 in Senna.

Key to Species:

1. Perfect stamens 7 of which the 2 or 3 lower ones are larger and the 3 upper ones reduced to staminodes
2. Pod subcylindrical; racemes short	C. planitiicola 9.
2. Pod flat, transversely ridged: racemes long
3. Plant glabrous	C. pleurocarpa 10.
3. Plant conspicuously pilose	C. notabilis 6.
1. Perfect stamens 10
4. Leaves reduced to phyllodes; leaflets usually absent, minutely hoary-pubescent (see also C. nemophila var. platypoda)	C. phyllodinea 8.
4. leaves usually with 1-10 pairs of leaflets, variously pubescent
5. Young leaves and twigs glabrous, viscid	C. glutinosa 3.
5. Young leaves and twigs glabrous or pubescent, not viscid
6. Young leaves and twigs glabrous, pruinose; stipules usually persistent	C. pruinosa 11.
6. Young leaves and twigs glabrous or pubescent, green or hoary; stipules caducous
7. Leaflets 1 or 2 pairs, glabrous or nearly so
8. Petiole and leaf rhachis flattened and subphyllodinous	C. nemophila var. platypoda 5c.
8. Petiole and leaf rhachis terete or nearly so
9. Leaflets broad and flat, ovate to obovate	C. oligophylla 7.
9. Leaflets terete to linear-elliptic
10. Leaflets terete	C. nemophila var. nemophila 5a.
10. Leaflets linear-elliptic	C. nemophila var. zygophylla 5d.
7. Leaflets 3-10 pairs; glabrous to densely pubescent
11. Petiole distinctly flattened; leaflets c. 3 pairs, elliptic	C. desolata var. planipes 2b.
11. Petiole terete; leaflets various
12. Plants glabrous or nearly so, green or grey; leaflet number and size very variable	C. nemophila var. coriacea 5b.
12. Plants pubescent, often densely so
13. Leaflets terete or nearly so, 3-10 pairs	C. artemisioides 1.
13. Leaflets channelled or flattened, broadly linear-elliptic to obovate, 3-6 pairs
14. Leaflets 4-6 pairs, lanceolate to oblong	C. sturtii 12.
14. Leaflets 3 or 4 pairs, elliptic to obovate
15. Leaflets c. 3 pairs, elliptic to ovate; 4-6 mm wide	C. desolata var. desolata 2a.
15. Leaflets 3 or 4 pairs, obovate-retuse; margins of leaf often recurved when dry	C. helmsii 4.

Author: Not yet available