Bot. Tidsskr. 4: 47. 1870.
Stems simple or branched, to 25 (–35) cm; branches 1–5 (or 6) pairs, from proximal, middle, or distal cauline nodes; cauline internode lengths 2–4 times subtending leaves. Leaves: blade usually broadly ovate, 3–16 mm, margins serrate, teeth 1–6 pairs, apices acute. Inflorescences beginning at node 3–5; bracts green or purplish adaxially, broader than leaves, broadly ovate or deltate, length not more than 2 times width, (4–) 5–9 (–11) mm, surfaces glabrous or setose and hairs eglandular, sometimes pubescent and hairs glandular, stalks 1-celled or 2-celled, 0.1–0.2 mm, teeth 3–6 pairs, as long as or much longer than wide, apices acute to acuminate. Flowers: corolla white, sometimes lilac, adaxial lip lilac, 6–11 (–13) mm, abaxial lip exceeding adaxial. Capsules oblong to elliptic or obovate, 4.5–8 mm, apex truncate to retuse.
B.C., N.B., N.S., Nfld. and Labr. (Nfld.), Ont., P.E.I., Que., Maine, Europe, Atlantic Islands (Iceland)
Subspecies 5 (2 in the flora).
The other three subspecies of Euphrasia arctica occur in Europe (P. F. Yeo 1978).
|1||Stem bases flexuous or decumbent; branches 1 or 2(–5) pairs, usually flexuous; bract surfaces glabrous or hairy, hairs eglandular bristles, teeth not much longer than wide; corollas 7–11(–13) mm.||Euphrasia arctica subsp. arctica|
|1||Stem bases erect; branches 1–5(or 6) pairs, usually straight; bract surfaces hairy, hairs glandular and eglandular bristles, teeth much longer than wide; corollas 6–8(–10) mm.||Euphrasia arctica subsp. borealis|
"broader" is not a number.