Immature female (left) and male (right) catkins. Aliso Canyon, Aliso and Wood Canyon Wilderness Park, Aliso Viejo, Orange County, CA. 11/21/12. © Peter J. Bryant |
White Alder Alnus rhombifolia A 50-80 ft. tall,
single-stemmed, deciduous tree that lives to be only about 100 years old. It is
scattered to locally frequent along water courses, especially in mountain
canyons in riparian forest and woodland; mountain foothills and Santa Ana
Mountains (Roberts). They are often found as a thicket of
small trees along a permanent stream. During floods, great stands of these trees
may be washed away and are rapidly replaced by dense masses of seedlings. The
root nodules contain the nitrogen-fixing bacteria Frankenia (Clarke). White
alder is used for firewood, as lumber, and as an ornamental. Native Americans
extracted red dye from the bark and used it for their baskets, and made a
perspiration-inducing tea from it, used in their sweat houses. Its greatest
value lies in the ability to protect watersheds and provide wildlife habitat. Back to Betulaceae of Orange County, California |
Immature male catkins. Aliso Canyon, Aliso and Wood Canyon Wilderness Park, Aliso Viejo, Orange County, CA. 11/21/12. © Peter J. Bryant |
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Male catkins, 1 to 4 in. long, in clusters of 2 to 7, are scalelike and pendulous. Aliso Canyon, Laguna Niguel, Orange County, CA. 1-22-12. © Peter J. Bryant |
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Immature female catkins (on the left) are spikelike. Aliso Canyon, Laguna Niguel, Orange County, CA. 1-22-12. © Peter J. Bryant |
Male catkin. Aliso Canyon, Laguna Niguel, Orange County, CA. 1-22-12. © Peter J. Bryant |
Male catkins. Arroyo Trabuco, Crown Valley to 2 mi. S, 12-2-12. © Ron Vanderhoff. |
Bark. Arroyo Trabuco, Crown Valley to 2 mi. S, 12-2-12. © Ron Vanderhoff. |
Male catkins. Arroyo Trabuco, Crown Valley to 2 mi. S, 12-2-12. © Ron Vanderhoff. |
Male and female catkins. Arroyo Trabuco, Crown Valley to 2 mi. S, 12-2-12. © Ron Vanderhoff. |
The alternate 4 in.-long oval leaves are prominently parallel-veined with a singly-serrated margin. The straight leaf veins are characteristic, and from the midvein, the veins run to the leaf margin. Upper surfaces are green and lower surfaces are yellowish green. They drop in the late fall while still green. Leaf margins are not rolled under, which distinguishes it from red alder which is found further north. Holy Jim Canyon, Trabuco Canyon, Orange County, CA. 12-29-11. © Peter J. Bryant |
Female catkins develop into 5/8 in. long woody cones superficially resembling conifer cones. Each cone scale has a tiny round winged nutlet, dispersed by flood and wind. Holy Jim Canyon, Trabuco Canyon, Orange County, CA. 12-29-11. © Peter J. Bryant |