Melampyrum pratense, L.

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 : 256

24. M. pratense L. , Sp. Pl. 603 (1753)

(inch M. laciniatum Koshewn. & V. Zinger ).

Stem 5-60 cm. Leaves 1-35 mm wide, linear to ovate. Bracts green, ovate- to linear-lanceolate, entire or hastate-dentate. Calyx 7-8 mm, glabrous except for strigulose veins; teeth 4-5 mm, linear. Corolla 10-18 mm, whitish to bright yellow, rarely with tube and upper lip tinged with purple; throat usually closed. Anthers 1-5-3-2 mm. 2n= 18. M ost o f Europe. Au Be Br Bu Cz Da Fe Ga Ge Hb He Ho Hs Hu It Ju Lu No Po Rm Rs (N, B, C, W, K, E) Su.

An extremely variable species, which has been treated differently by every author who has studied it closely. Several variants have been recognized as subspecies on the strength of differences in the colour of the corolla and of the degree of closure of its throat (e.g. subsp. purpureum (Hartman) Soó , Feddes Repert. 24: 183 (1927), and subsp. hians (Druce) Beauverd in Schinz & R. Keller, FI. Schweiz ed. 3, 2: 309 (1914)). It has been shown, however, that at least in some parts of Europe these distinctive characters are distributed sporadically through populations which are otherwise typical, and show no certain correlation with other characters. Other variants recognized as subspecies (e.g. subsp. commutatimi (Tausch ex A. Kerner) C. E. Britton, Trans. Proc. Bot. Soc. Edinb. 33: 371 (1943), and subsp. alpestre Ronniger , Viert. Naturf. Ges. Zürich 55: 322 (1910)), although they may show a fairly well-defined geographical range, are distinguished mainly or entirely by characters which are used to define the ecotypic variants, so that a very confusing taxonomic situation results. It is also apparent that a large part of the infraspecific variation is clinal (usually from north to south), without any appreciable discontinuities. It seems best, therefore, in the present state of our knowledge not to give formal recognition to any infraspecific taxa, but to refer the reader to the literature cited.