The Alnus Rhombifolia is commonly known as the Sierra Alder as well as White Alder.
The currently accepted scientific name for white alder is Alnus rhombifolia Nutt. . There are no recognized subspecies, varieties, or forms.White alder is distributed from the Pacific coast of Baja California, north in the coastal valleys to just north of San Francisco Bay, in the interior foothills of the Coast Ranges and low to mid elevation slopes of the Sierra Nevada. It is found farther north along the lower eastern slopes of the Cascades in Oregon and Washington and in the dry interior valleys of Oregon, extending into southern British Columbia. It extends eastward along the main tributaries of the Columbia River to the lower valleys of southeastern and south-central Washington, and northeastern Oregon, reaching its eastern limits in Idaho along the Clearwater and Snake Rivers .White alder is restricted to riparian woodland communities. In these communities it is often found with Fremont cottonwood (Populus fremontii), California sycamore (Platanus racemosa), willows (Salix spp.), ash (Fraxinus spp.), California live oak (Quercus agrifolia), valley oak (Q. lobata), and Douglas-fir (Pseudotsuga menziesii) . Plublished classification schemes listing white alder as a dominant part of the vegetation in community types (cts), habitat types (hts), or plant associations (pas) are presented below: Area Classification Authority CA hardwood forest&woodland cts Barbour 1987 s CA general veg. pas Paysen & others 1980 CA:San Gabriel Mts general veg. cts Hanes 1976 CA:Santa Ana&San general veg. cts Vogl 1976 Jacinto Mts CA:San Bernardino general veg. cts Minnich 1976 Mts sw USA wetland cts Brown 1979 e Wa,nID steppe hts Daubenmire 1970Some of the information provided here is attributed to:Uchytil, Ronald J. 1989. Alnus rhombifolia. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). , available at the USDA Fire Effects Information System (FEIS) website