White alder is a fairy common riparian tree with smooth whitish to gray bark growing 30' to 100' tall.  The leaves are alternate, oblong-ovate, serrate-margined, rounded to acute-tipped, very prominently veined with the veins extending to the leaf margin, dark green above and lighter beneath, and from 1-1/2" to 4" long.  They are on petioles to 1" long and are deciduous in the fall while still green.  The male catkins appear in the fall, generally 2-several per cluster, and flower early in the spring while the branches are all mostly leafless.  They are scalelike and pendulous.  The female catkins develop into small, woody cones about 1/4" to 3/4" long.  White alder is usually found either singly or in small stands along permanent streams below 7000' in shaded canyons and in the lower mountains, and is the only member of the birch family likely to be found in Southern California.  These pictures were taken in Eaton Canyon in Altadena.

Click here for Latin name derivations: 1) Alnus 2) rhombifolia.
Pronunciation: AL-nus rom-bi-FO-lee-a.
Click here for Botanical Term Meanings.