Though the fondness of this species for the seeds of flax (Linum) and hemp (Cannabis) has given it its common name in so many European languages,' it feeds largely, if not chiefly in Britain on the seeds of plants of the order Compositae, especially those growing on heaths and commons.
The flax plant (Linum usitatissimum) belongs to the natural order Linaceae, and, like most plants which have been long under cultivation, it possesses numerous varieties, while its origin is doubtful.
For instance, in Primula and Linum some flowers have long stamens and a pistil with a short style, the others having short stamens and a pistil with a long style.