Alder: From the Plant and Flower Alphabet
GBD MICROSITE PLANT 
& FLOWER ALPHABET
With a few exceptions, alders are deciduous, and the leaves are alternate, simple, and serrated. The flowers are catkins with elongate male catkins on the same plant as shorter female catkins, often before leaves appear; they are mainly wind-pollinated, but also visited by bees to a small extent.
The largest species are red alder (A. rubra) on the west coast of North America, and black alder (A. glutinosa), native to most of Europe and widely introduced elsewhere, both reaching over 30 metres (100 ft). By contrast, the widespread Alnus alnobetula (green alder) is rarely more than a 5 m-tall (16 ft) shrub.
Engravings from “Handbook of Plant and Floral Ornament from Early Herbals” by Richard G. Hatton (Originally published in 1909).
Plant descriptions primarily from Wikipedia.
