Stem 1.5-8 dm, simple or few-branched, thinly villous-puberulent on 2 of the 4 sides; lvs lance-triangular to oblong, firm, serrate or crenate-serrate, 2-6 cm נ4-15 mm, scabrous above, scabrous-hispidulous beneath; bracts gradually reduced upwards, mostly shorter and broader than the lvs, with longer and sharper teeth; cor 9-14 mm; mature cal 12-17 mm; 2n=14, + 0-8 B. Various habitats; circumboreal, s. in Amer. to N.Y., Colo., and Oreg., our lowland plants intr. from Europe, the alpine ones native. (R. borealis; R. kyrollae; R. minor; R. oblongifolius; R. stenophyllus)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.