Much like no. 9 [Sabatia dodecandra (L.) Britton, Sterns & Poggenb.]; branches mostly opposite; lvs lanceolate to lance-linear; cal-lobes broadest at the base, the middle less than 1 mm wide, obscurely 1-3-nerved or apparently nerveless; cor-lobes 15-30 mm, at least a third as wide; 2n=40. Fresh-water marshes and margins of streams or ponds on the coastal plain; interruptedly from N.S. to S.C. July-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.