Erect perennial 4-8 dm, branched above; lvs sessile, lanceolate or narrowly elliptic to lance-ovate, the lower obtuse or subacute, the upper acute; infl many- fld, less compact than no. 16 [Hypericum punctatum Lam.]; fls 15-25 mm wide, sep lanceolate, acute or acuminate, 5-7 mm, conspicuously black-dotted; pet 8-12 mm, conspicuously dotted; stamens many, fascicled; styles 6-10 mm, seldom persistent; stigmas capitate; fr 5-7 mm, glandular as in no. 16; 2n=16. Moist or dry soil; Ill. to Okla., s. to Fla. and Tex. June-Aug.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.