122 Zostera marina L.

This widespread sea-water species occurs in Eurasia and N. America. It avoids, however, the arctic waters. The population in eastern N. America is distinguished as var. stenophylla Asch. & Graebn. The species belongs to the circumpolar plants (Hultén, Circumpol. I, p. 256 and map 186), although there are wide gaps in the distribution. The map is, however, incomplete in same parts, for instance S. and SE. Europe. Cf. also Meusel et al. 1965, map p. 26.