Much like no. 1 [Mimulusringens L.], and hybridizing with it, but the lvs tapering to a narrowly winged petiole 1-2 cm, the blade lanceolate to ovate, more sharply and coarsely toothed; pedicels at anthesis mostly 2-10 mm, to 15 mm in fr; 2n=22. Wet woods and shady streambanks; Conn. to s. Ont., s. Mich., Io., and Kans., s. to Fla. and Tex. July, Aug. Hybridizes with no. 1 [Mimulus ringens L.].
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
This species is more or less frequent in all of the southern half of the state, becoming less frequent northward until the Wabash River is reached. North of the Wabash River there are specimens from only Allen and Warren Counties.