Atlas of North European vascular plants
Hultén & Fries 1986
1520 Galium pumilum Murr.
Syn.: G. sylvestre Poll.
This polymorphic species is restricted to Europe. Some subspecies or closely related species are distinguished (Fl. Eur. 4/1979, p. 31 f.), each with its specific distribution area. Subsp. normanii (O. C. Dahl) Nordh. occurring on Iceland and in two places in Nordland (Norway) is of special geographic interest. Most of the occurrences in Fennoscandia are adventive (subsp. vulgatum Sterner).