This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Herbs, shrubs, or in tropical regions trees, with evenly pinnate leaves, not sensitive to the touch, and mainly (in all our species) yellow flowers. Calyx-teeth nearly equal, mostly obtuse, generally longer than the tube. Corolla nearly regular; petals 5, spreading, nearly equal, imbricated, clawed. Stamens usually 10, sometimes 5, often unequal and some of them imperfect; anthers all alike, or those of the lower stamens larger, opening by 2 pores at the summit. Ovary sessile or stalked; ovules 00. Pod flat or terete, often curved, septate or continuous between the seeds, the valves not elastically dehiscent. Seeds numerous. [Ancient name.]
About 200 species, of wide distribution in warm and temperate regions, very abundant in tropical America. Besides the following, about 15 others occur in the southern and southwestern States. Type species: Cassia fistula L.
Leaflets 6 or 4, broadly obovate.
Leaflets 8-20, oblong or ovate-lanceolate.
Perennial; leaflets oblong, obtuse.
Segments of the pod at least as long as broad; petiolar gland club-shaped.
Segments of the pod much shorter than broad; petiolar gland cylindric to conic.
Annual; leaflets ovate-lanceolate, acute or acuminate.
Cassia Tora L. Sp. Pl. 376. 1753. Cassia obtusifolia L. Sp. Pl. 377. 1753.
Annual, glabrous, 1 1/2°-2° high, branched or simple. Stipules linear-subulate, at length deciduous; leaves petioled, the gland borne between or above the lowest pair of leaflets; leaflets 2-4 pairs, thin, obovate, obtuse and mucronulate at the apex, narrowed or rounded at the base, 1'-1 1/2' long, often 1' wide; flowers 6"-12" broad, few, in short axillary racemes; calyx-lobes oblong, obtuse; stamens 10, the anthers of the upper 3 imperfect; pod linear, very slender, strongly curved, 4'-6' long, about 1 1/2" wide.
Cassia marilandica L. Sp. Pl. 378. 1753.
Perennial, glabrous or pubescent with a few scattered hairs, 3°-8° high, little branched. Stipules subulate-linear, caducous; leaves petioled, the club-shaped gland borne near the base of the petiole; leaflets 12-20, oblong or lanceolate-oblong, obtuse or obtusish, mucronate, rounded at the base, ciliate, 1'-2' long, 3"-6" wide; flowers 7"-9" broad, numerous in pubescent axillary racemes on the upper part of the plant; calyx-lobes ovate or oblong, obtuse; stamens 10, the upper 3 imperfect; pod linear, flat, pubescent or becoming glabrous, 3'-4' long, 3" wide, curved, its segments as long as broad or slightly longer; seeds flat, suborbicular.
Cassia Medsgeri Shafer, Torreya 4: 179. 1904.
Biennial (?) or perennial, similar to C. marilandica, glabrous or very nearly so throughout. Stipules linear-lanceolate; petiolar gland cylindric to conic; leaflets 8-16, oblong to elliptic, mucronate, glabrous, slightly glaucous beneath, 2' long or less; inflorescence glabrous or nearly so; pod curved, linear, little compressed, 4' long or less, tardily dehiscent, its segments much shorter than broad; seeds obovoid, 2" long, 1" thick.
In dry gravelly soil, Pennsylvania to Georgia, Iowa, Kansas and Texas. July-Sept.
Cassia occidentalis L. Sp. Pl. 377. 1753.
Annual, glabrous, much branched, erect, 4°-6° high. Stipules caducous; gland short, borne near the base of the petiole; leaflets 8-12, ovate or ovate-lanceolate, acute or acuminate at the apex, rounded at the base, 1'-2' long, 4"-9" wide; flowers 7"-9" broad, in short axillary racemes; stamens 10, the upper 3 imperfect; calyx-lobes oblong, obtuse; pod linear, glabrous, 4'-6' long, about 3" wide, somewhat curved, its margins thickened.
In waste places, Virginia to Indiana, Kansas, Florida and Mexico, and throughout tropical America, extending to Chili and Uruguay. Also in the warmer parts of the Old World. In our area adventive from the South. Coffee-weed. The seeds are known as negro or magdad coffee. July-Aug.