Centaurium erythraea, Rafn

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 : 57-58

2. C. erythraea Rafn , Danm. Holst. FI. 2: 75 (1800).

Biennial (3-)10-50 cm. Stem usually solitary, sometimes several, usually branched in the upper part. Rosette-leaves 1-5 x 0-8-2 cm, obovate to elliptical, usually obtuse, 3- to 7-veined; cauline leaves usually much smaller and narrower, often acute, 3-veined. Flowers of variable size, pink to pinkish-purple, rarely white, in a dense or lax corymbiform cyme. Calyx j - i as long as, rarely nearly equalling the corolla-tube. Dry grassland, scrub and mountain slopes. Europe, northwards to c. 61° N. in N. W. Russia. All except F a Fe Is N o Sb. Variable in branching of the stem, shape and size of the leaves, presence or absence of scabridity on the stem, leaves, bracts and on the calyx, density of the inflorescence, size of the flowers, length of the calyx in relation to the corolla-tube, length of the anthers, etc. Populations showing different combinations of these characters and occupying more or less restricted areas have been treated by different authors as species, subspecies or varieties. In many cases, however, these taxa are linked by transitional forms. The following subspecies appear to be reasonably distinct.

1 Stem branched usually from the base or middle; rosette-leaves oblanceolate or narrowly elliptical, ±acute; flowers usually pedicellate, in a lax corymbiform cyme; corolla-lobes usually acute; calyx usually as long as the corolla-tube; capsule distinctly exceeding the calyx

2 Upper part of stem, bracts and calyces scabrid; calyx sometimes i as long as the corolla-tube; corolla-lobes usually

5-7 mm, pink, more than | as long as the tube

(e) subsp. rhodense 2 Stem, bracts and calyces smooth; calyx as long as the corolla-tube; corolla-lobes usually 8-10 mm, usually equalling or longer than the tube, deep pink (f) subsp. majus

1 Stem branched usually in the upper part; rosette-leaves obovate or elliptical, usually obtuse; flowers sessile or subsessile, fasciculate, in a ± dense corymbiform cyme; corolla-lobes obtuse; calyx usually c. | as long as the corolla-tube; capsule slightly exceeding the calyx

3 Corolla-lobes usually 6-8 mm, usually equalling the tube

(d) subsp. grandiflorum 3 Corolla-lobes usually less than 6 mm; usually c. | as long as the tube

4Corolla-lobes usually 2-5-5 mm, middle cauline leaves ±linear-oblong; inflorescence fairly lax (c) subsp. rumelicum 4Corolla-lobes usually 5-6 mm; middle cauline leaves lanceolate, narrowly lanceolate or narrowly elliptical; inflorescence dense

5 Stem, margin of leaves, bracts and calyx smooth

(a) subsp. erythraea 5 Stem, margin of leaves, bracts and calyx scabrid

(b) subsp. turcicum