Betula (betula)

[L., the birch, also spelled betulla (> It. betula, betulla, also bedello, = Pg. = betulla Sp. abedul = F. dim. bouleau ); cf. Corn. betho, bezo =Bret. bezo W. bedw =Gael. beth Ir. beth, be it, the birch.] A genus of hardy trees or shrubs, natives of the north temperate and arctic regions; the birches. It is the type of the order Betulaceæ, and is distinguished from the accompanying genus Alnus by a difference of habit and by its winged nutlet. There are about 30 species of Betula, of which 10 are North American.