Monographs Details: Cassia oligosperma Mart. ex Benth.
Authors:Howard S. Irwin, Rupert C. Barneby
Authority: Irwin, Howard S. & Barneby, Rupert C. 1978. Monographic studies in Cassia (Leguminosae, Caesalpinioideae). III. Sections Absus and Grimaldia. Mem. New York Bot. Gard. 30: 1-300.
Family:Caesalpiniaceae
Description:Species Description - Viscid subshrubs with flexuously humifuse or weakly assurgent, freely branching stems to 3-10 dm radiating from a woody root, throughout minutely villosulous and weakly hispid with yellow setae up to (0.3-)0.45-1.7 mm, the many small glutinous lfts concolorous, the few-fld racemes incurved to vertical from the mat of foliage, mostly borne on weak axillary branchlets. Stipules erect, firm, narrowly subulate or linear, 1.2-2.2 mm, persistent. Lvs ascending or divaricate, (2-)3-8 cm, petioled; pulvinus discolored but scarcely swollen, 0.8-1.2 mm; petiole 1.5-15(-22) mm, at middle 0.5-0.7 mm diam, narrowly thick-margined, the sulcus almost closed; rachis 2-6 cm; lfts (6-)7-18 pairs, of about equal size, widely spreading from rachis, tilted edgewise on linear, commonly livid pulvinule 0.2-0.7 mm, in outline when short obovate or ovate-elliptic mostly obtuse or emarginate, when longer narrowly lance-oblong or oblong-elliptic, obtuse or acute, all callous-mucronulate, 1.5-15 x 1-5 mm, at base shallowly cordate both sides or merely rounded on distal one, the entire margin a trifle thickened but not revolute, the blades on both sides olivaceous, glutinously sublustrous, usually both finely puberulent and at least remotely setulose, above rarely glabrescent, the midrib prominulous beneath but the 1-3 pairs of secondary veins either immersed or only faintly raised on one or both sides. Racemes subsessile, mostly terminal to slender or subfiliform, leafless or few-lvd axillary branchlets, occasionally lf-opposed, loosely 3-15-fld, the often abruptly flexuous or sinuous axis becoming 1-5 cm, the 1-2 expanded fls raised about to level of the subcorymbose buds; bracts herbaceous, green or purplish, linear-elliptic or narrowly ovate, 1.2-2.4 mm, persistent; pedicels (fertile) at anthesis ascending, in fruit thickened, usually sigmoidally deflexed and abruptly geniculate both ends, 1.1-2 cm, bracteolate 1-6 mm below calyx; bracteoles resembling bracts, slightly smaller; buds subglobose, finely puberulent and glutinously yellow-setose; sepals submembranous, reddish, elliptic or elliptic-oblanceolate, obtuse, 6-7 x 2.6-3.4 mm; petals orange, the four plane ones spathulate-obovate, narrowed to a slender claw, slightly unequal, ± 9.5-11 x 4-6.5 mm, the dimidiate coiled petal about as long; ovary both gray-villosulous and setulose; ovules ± 4. Pod oblong, 2.2-3.2 x 0.7-0.85 cm, the reddish-brown valves nigrescent in age, minutely villosulous and weakly yellow-setulose; seeds unknown. — Collections: 6.

Distribution and Ecology - Cerrado, in sandy soils, 800-950 m, apparently rare, known only from the type station on the w. slope of Serra do Espinhaco in n.-centr. Minas Gerais (near 16° 30' S) and from Serra Geral de Goias near the Bahia border between 12° and 14° S (Serra do Ouro s. to Posse). — Fl. III-VIII.

Discussion:

A strongly individual cassia, suggesting a combination of C. fagonioides and some form of C. neesiana, having the diffusely branched, often humifuse stems, intensely sticky foliage, and orange petals of the former, but the multijugate leaflets of the latter. Size and number of leaflets vary greatly, but not in correlation; furthermore the largest and smallest known were collected close together in Serra Geral de Goias (Irwin & al. 14489, 14938).

Distribution:Minas Gerais Brazil South America| Goiás Brazil South America| Bahia Brazil South America| Brazil South America|