Erect perennial, 1-2 m, glabrous or sparsely villous above; stipules lance-linear; petiolar gland short-cylindric or rounded or dome-shaped; lfls commonly 4-8 pairs, oblong or elliptic, 2-5 cm, acute or obtuse, mucronate; infl of several axillary racemes, less floriferous than no. 1 [Senna hebecarpa (Fernald) H. S. Irwin & Barneby]; buds nodding; sep unequal; pet 10-15 mm, slightly dissimilar; ovary appressed-hairy; pods glabrous or with scattered minute incurved hairs, tardily dehiscent, 6-10 cm x 8-11 mm, the joints about twice as wide as long; seeds nearly twice as long as wide, plump, with depressed center; 2n=28. Moist open woods and streambanks; s. N.Y. to s. Wis. and e. Neb., s. to Fla. and Tex. July, Aug. (Cassia m.; C. medsgeri; Ditremexa medsgeri)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Infrequent in the southern third of the state, becoming rare northward, and probably entirely absent from the northern counties. It is found mostly in low ground along roadsides and in low woodland and alluvial bottoms along streams. This species is often confused with the preceding one [Senna hebecarpa] from which it is easily separated by the characters given in the key. The pubescence of Senna marilandica is appressed while that of Senna hebecarpa is spreading. The plant is a darker green, flowers a little later, and is not as aggressive as the preceding.
Indiana Coefficient of Conservatism: C = 4
Wetland Indicator Status: FACW
Diagnostic Traits: perennial to 2 m; leaves evenly once-pinnate; petioles with cylindrical to conical gland; stamens 3 sterile, 7 fertile; ovules 20-25; legumes 5-10 cm × 7-11 mm, segments much shorter than wide, glabrous or with short, appressed-hairs.