| # The genera of Leguminosae-Caesalpinioideae and Swartzieae |

L. Watson and M.J. Dallwitz

### Cassia L.

Cathartocarpus Pers., Bactyrilobium Willd., Cassia subgen. Fistula (DC) Benth., Cassia subgen. Cassia de Wit

Type species: C. fistula L.

Habit and leaf form. Herbs; unarmed.

Phyllotaxy distichous, or spiral. The leaves compound; pinnate (without petiolar glands); paripinnate. The leaflets many per leaf, or few per leaf; opposite or sub-opposite; petiolulate; without noticeably twisted petiolules; symmetrical or nearly so; pinnately veined, with a predominant ‘midrib’. Stipules absent or early caducous or very inconspicuous in mature leaves, or present, persistent and conspicuous in mature leaves (?); if present, leafy, or membranous; not connate. Stipels absent.

Inflorescence and floral morphology. The inflorescences axillary, or terminal (sometimes cauliflorous); unbranched, or branched; when branched, of racemose units; simple racemes, or panicles. The flowers not distichous. Bracts absent at anthesis, or persistent beyond anthesis (?). Bracteoles present (these at or near the base of the pedicel); absent at anthesis, or persistent beyond anthesis; free.

The flowers hermaphrodite; pentamerous; coloured. Floral tube length relative to total hypanthium + calyx length when applicable, about 0.25. Hypanthium absent, the androecium hypogynous. Calyx 5; covering the rest of the flower in bud; gamosepalous, or polysepalous; more or less regular, or markedly irregular; members imbricate. Corolla present; more or less regular, or slightly irregular (sub-isomorphic); spreading, 5; without greatly reduced members; polypetalous. Petals clawed, or sessile, or clawed and sessile; imbricate; imbricate-ascending; yellow, or red. Disk absent. The androecium comprising 10 members; characterized by the long, sigmoidally incurved filaments of the three abaxial stamens being many times longer than their small anthers, which are dorsifixed, sub-versatile and introrsely dehiscent via short slits, contrasting with the short adaxial stamens with their straight filaments and anthers dehiscing via basal pores (Cassia); declinate (and strongly accrescent towards the abaxial side of the flower); members all free of one another; members markedly unequal; including staminodia, or comprising only fertile stamens (the small anthers of adaxial members sometimes indehiscent). Fertile stamens (6–)10 (?). Anthers attached at the base of the connective, or attached at the base of the connective and attached well above the base of the connective (?); dehiscing via pores or short slits and longitudinally (those of the three long stamens usually dehiscing introrsely by short slits, the others by basal pores). Ovary sessile or subsessile, or stipitate; centric, free. Stigma slightly dilated to not dilated. Ovules numerous.

Fruit, seed and seedling. Fruit always indehiscent; not drupaceous; straight, or curved (elongate, cylindric or more or less compressed, pulpy or pithy within); internally septate (divided by transverse septa into one rank of seeds, or these 2-ranked a via an additional, longitudinal septum); without markedly twisting or enrolling valves; becoming woody, or not becoming woody. The mature valves with conspicuous, prominent, raised venation, or without prominent venation; conspicuous venation predominantly longitudinal, or not predominantly longitudinal. Seeds compressed dorsiventrally, endospermic; not arillate (the funicle filiform); with a straight or slightly oblique radicle; amyloid-negative; with galactomannan. Cotyledons of Type 1, or Type 2, or Type 3 (?); with a vascular system in one plane; epigeal.

Transverse section of lamina. Leaves without conspicuous phloem transfer cells in the minor veins. Druses common in the mesophyll, absent from the mesophyll. Mesophyll secretory cavities absent. Adaxial hypodermis absent. Leaf girders common (the veins transcurrent). Laminae dorsiventral. Mesophyll without unaligned fibres or sclereids. Minor veins mainly with abundant accompanying fibres.

Leaf lamina epidermes. Epidermal crystals not seen either adaxially or abaxially. Simple unbranched hairs common; scabrid, or smooth. No compound or branched eglandular hairs seen. Capitate glands not seen. Hooked hairs present, or not seen. Cassieae-type leaf pseudo-glands not seen. Expanded and embedded hair-feet absent. Basally bent hairs present. Adaxial: Adaxial interveinal epidermal cell walls straight in optical section; conspicuously pitted; of medium thickness. Stomata adaxially very rare. Abaxial: Abaxial stomata predominantly paracytic. Abaxial epidermis papillate interveinally, or not papillate; with the papillae not over-arching the stomata. Abaxial interveinal epidermal cell walls straight, or gently undulating; not conspicuously pitted in optical section; scarcely staining with safranin; thin.

Wood anatomy. Wood with septate fibres, or without septate fibres; not storied; without normal intercellular canals; without traumatic canals. Intervascular pits medium to large.

Pollen ultrastructure. Tectum punctate, or reticulate; smooth punctate, or puncticulate, or rugulose punctate; rugulose reticulate. Length of colpi greater than one half pole to pole distance, or less than one half pole to pole distance (rarely).

Cytology. Basic chromosome number, x = 14. 2n = 24, or 28.

Species number and distribution. About 30 species. Circumtropical, in the Americas, Africa and Madagascar, Asia, Malesia and Australia.

Tribe. Cassieae.

Comments. Widely cultivated.

Miscellaneous. Illustrations: • Cassia leiandra: Fl. Brasiliensis 15 (1870). • Cassia excelsa (cf. C. fistula): Fl. Brasiliensis 15 (1870). • Cassia fistula: Baillon, Histoire des Plantes 2 (1870). • Cassia mannii: Steyaert, in Fl. du Congo Belge (1952). • Cassia fistula: Schery, Ann. Miss. Bot. Gard. 38 (1951). • Cassia grandis: Schery, Ann. Miss. Bot. Gard. 38 (1951). • C. moschata: Schery, Ann. Miss. Bot. Gard. 38 (1951). • Cassia spectabilis: Schery, Ann. Miss. Bot. Gard. 38 (1951). • Cassia angustifolium, e.m. scanned pollen (Graham & Barker, 1981). • Cassia maxonii, e.m. scanned pollen (Graham & Barker, 1981). • Cassia moschata, e.m. scanned pollen (Graham & Barker, 1981).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classification. See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1993 onwards. The genera of Leguminosae-Caesalpinioideae and Swartzieae: descriptions, illustrations, identification, and information retrieval. In English and French. Version: 4th August 2019. delta-intkey.com’.

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