Stems 3-7 dm, equally pubescent on all 4 sides with minute recurved hairs; lvs lanceolate to lance-ovate, the main ones 5-10 cm, on petioles 3-10 mm; peduncles axillary from a few median nodes, 2-10 cm, bearing at the summit a pair of foliaceous bracts and 1-3 short- pediceled fls; cal-lobes very narrowly linear; cor 3-5 cm, the tube equaling or slightly longer than the throat; fr finely hairy; 2n=34. Dry or rocky upland woods; s. Ill. and Mo., s. to La. and Tex.; also in the Appalachian region from Md. to Ga. and Ala. June-Aug. (R. purshiana Fernald, the Appalachian plants) There are cleistogamous forms, as in no. 1 [Ruellia strepens L.]
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.