Frangula californica (Eschsch.) A.Gray
Rhamnus californica (syn. Frangula californica), commonly known as coffeeberry and California buckthorn, is a species of flowering plant in the family Rhamnaceae, the buckthorns. It is native to the southwestern United States and Baja California in Mexico. It is an introduced species in Hawaii.
Rhamnus californica is variable in form across subspecies. In favorable conditions the plant can develop into a small tree over 6 meters tall. More commonly it is a shrub between 1 and 2 meters tall. The branches may have a reddish tinge and the new twigs are often red in color. The alternately arranged evergreen leaves are dark green above and paler on the undersides. The leaves have thin blades in moist habitat, and smaller, thicker blades in dry areas. The small greenish flowers occur in clusters in the leaf axils. The fruit is a juicy drupe which may be green, red, or black. It is just under a centimeter long and contains two seeds that resemble coffee beans. This plant can live an estimated 100 to 200 years.
This shrub is a member of many plant communities and grows in many types of habitat, including chaparral, coastal sage scrub, and woodlands. It grows in forest types such as foggy coastal oak forests, redwood forests, and mountain coniferous forests. It can be found alongside chaparral whitethorn (Ceanothus leucodermis), toyon (Heteromeles arbutifolia), skunkbush (Rhus trilobata), redberry (Rhamnus crocea), and western poison oak (Toxicodendron diversilobum). In brushy mountain habitat it grows among many species of manzanita.
The plant reproduces sexually by seed and vegetatively by sprouting. After wildfire or cutting, the plant generally resprouts from its root crown. Reproduction via seed is most common in mature stands of the plant. It produces seeds by 2 or 3 years of age. Seeds are mature in the fall. Seed dispersal is often performed by birds, which are attracted to the fruit; some plants are so stripped of fruit by birds that hardly any seeds fall below the parent plant.
This long-lived plant is persistent and becomes a dominant species in many habitat types, such as coastal woods. In the absence of wildfire, the shrub can grow large, with a wide spread that can shade out other flora. When fire occurs, the plant can be very damaged but it readily resprouts from the surviving root crown, which is covered in buds for the purpose. It reaches its pre-burn size relatively quickly.
- Rhamnus californica subsp. californica - widespread in western California. Fruit with two seeds; twigs red; leaves with conspicuous veins.
- Rhamnus californica subsp. occidentalis - northern California and southwest Oregon, on serpentine soils. Fruit with three seeds; twigs brown; leaves with inconspicuous veins.
- R. californica 'Eve Case', up to 10 feet tall and wide
- R. californica 'Leatherleaf', with black-green foliage
- R. californica 'Mound San Bruno', short and compact
Food and medicine
Native Americans of the west coast of North America had several uses for the plant as food and medicine. The Ohlone people used the leaves to treat poison oak dermatitis. The Kumeyaay people used the bark for this purpose. The Kawaiisu used the fruit to treat wounds such as burns. The bark was widely used as a laxative. Several groups ate the fruit fresh or dried.
|Wikimedia Commons has media related to Rhamnus californica.|
- Frangula californica. Germplasm Resources Information Network (GRIN).
- Frangula californica. NatureServe. 2012.
- McMurray, N. E. 1990. Rhamnus californica. In: Fire Effects Information System. USDA FS. Rocky Mountain Research Station, Fire Sciences Laboratory.
- Frangula californica. Native American Ethnobotany. University of Michigan, Dearborn.
- Chesnut, V. K. (1902). Plants used by the Indians of Mendocino County, California. Government Printing Office. p. 407. Retrieved 24 August 2012.