Galium rivale, (Sibth. & Sm.) Griseb.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1976, Flora Europaea. Volume 4. Plantaginaceae to Compositae (and Rubiaceae), Cambridge University Press : 20

12. G. rivale (Sibth. & Sm.) Griseb. , Spicil. FI. Rumel. 2: 156 (1844)

( Asperula rivalis Sibth. & Sm. , A. aparine Bieb. ).

Stem (70-)90-120 cm, ascending from a slender base, stout. Leaves (20-)30-40(-45) x 4-8(-10) mm, ovate to oblanceolate, abruptly or gradually narrowing to the awned apex, rather rough above. Inflorescence rather broadly ovoid; pedicels 0*5-3 mm, glabrous, rarely pubescent. Corolla 1 *8-3 mm, infundibuliform, rarely crateriform; tube 0-9-1 -5 mm; lobes 0*8-2 mm, broadly to narrowly ovate. Filaments 0*2-0*6 mm; anthers О-3-О-5 mm, suborbicular to oblong. Fruit 1-1*2 mm, granulate, glabrous, rarely somewhat pubescent. 2л = 66. Damp scrub and riverbanks. S.E. & E.C. Europe, extending northwards to Estonia. Au Bu?Cr Cz Gr Hu Ju Po Rm Rs (B, C, W, K, E) Tu.

G. rivaleforms a very variable polyploid complex. In the western and northern parts of its range the populations consist mainly of plants with relatively narrow leaves, long filaments and short anthers, while in the southern and eastern, the plants usually have wide leaves, short filaments and long anthers. In the Balkan peninsula especially, transitional populations with intermediate characteristics occur. Any question of distinguishing two species in E. Europe (cf. Asperula rivalis and A. aparine in Fl. URSS 23: 274-275 (1958)) must be considered in the light of further investigation of populations in Asia.