Genus Alnus

Alder is the common name of a genus of flowering plants belonging to the birch family .

Species in the genus Alnus of plants

Black alder - Alnus glutinosa is a tree that thrives in moist soils, and grows under favourable circumstances to a height of 2030 m, exceptionally up to 37 m,

Seaside alder - Alnus maritima is considered a large shrub or small tree and is the only autumn-blooming member of its genus native to North America. All other North American alders bloom in the spring. The autumn-blooming phenology is a characteristic that Alnus maritima shares with two old-world Alnus species, Alnus nitida and Alnus nepalensis, which are endemic to southeast Asia. This profound similarity in their timing of anthesis has led to their classification as the only three members in the subgenus Clethropsis.