Polygonum arenastrum, Boreau

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1964, Flora Europaea - Volume 1. Lycopodiaceae to Platanaceae, Cambridge University Press : 79

18. P. arenastrum Boreau , Fl. Centr. Fr. ed. 3, 2: 559 (1857)

( P. aequale Lindman , P. littorale auch, pro parte, P. aviculare auct. ross.).

Annual. Stems usually less than 30 cm, procumbent, freely branched, forming a mat. Leaves 5-20 x 2-5-5 mm, elliptical or lanceolate, more or less uniform in size. Ochreae silvery-hyaline with few, faint veins, less than half as long as internodes. Flowers solitary or in few-flowered axillary clusters. Perianth-tube at least half as long as segments. Nut 1-5-2-5 mm, included in perianth, dull, often with one side much narrower than the other two. 2n = 40. Probably throughout most o fEurope, except the extreme north; distribution imperfectly known. P. calcatimi Lindman, Bot. Not. 1904: 139 (1904) is like 18 but is often more slender and even more closely appressed to the ground. The leaves are smaller, the perianth-tube half as long as the segments, and the nut glossy and smooth (more rarely punctulate). It is recorded in N. Europe, southwards to Britain, Germany, Romania and C. Russia, but does not seem to merit recognition as a distinct species. P. acetosellum Klokov , Jour. Agr. Bot. (Kharkov) 1 (3): 171 (1927), described from E. Ukraine, and P. propinquum Ledeb. , FI. Ross. 3: 532 (1850) from N. Ukraine and S.E. Russia, are very similar.