Euphrasia arctica subsp. tenuis, (Brenner) Yeo

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1972, Flora Europaea. Volume 3. Diapensiacea to Myoporaceae, Cambridge: Cambridge University Press : 261-262

(a) Subsp. tenuis (Brenner) Yeo , Bot. Jour. Linn. Soc. 64: 357 (1971)

( E. officinalis var. tenuis Brenner , E. tenuis (Brenner) Wettst. 1896 , non Wettst. 1893):

Stem with 0-3(-4) pairs of usually rather short branches. Cauline internodes (l|-)2 j-6 (-9) times as long as leaves. Lowest flower at node 3-6(-9). Leaves often with glandular hairs, the cauline 3—14(—16) mm, mostly broadly ovate, trullate or oblong; lower floral leaves 5-12(-16)mm, broadly ovate to oblong-ovate, rounded to subcordate at base, with 3-6 pairs of subacute to aristate teeth. Corolla (6-5-)8-10 mm. Capsule 5-8 mm, at least as long as calyx, at least twice as long as wide, elliptic-oblong to obovate. 2n = 44. From Iceland to C. Russia.

Plants approaching 11(b) occur in Norway but have glandular hairs. In the Baltic region plants intermediate between 11(a) and 17 are found.