Stem almost always simple, 3-10 cm; foliage-lvs 2-5 pairs, ovate to suborbicular, 2-7 mm, increasing in size toward the summit, with 2-3 rounded teeth on each side; infl densely crowded and head-like; otherwise as no. 3 [Euphrasia randii Rob.]. Alpine situations from Lab. and Nf. to the higher peaks of Me. and N.H. (E. williamsii)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.