Juglans californica
From Wikipedia, the free encyclopedia
| California Walnut | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 California Black Walnut
|
||||||||||||||
| Scientific classification | ||||||||||||||
|
||||||||||||||
| Binomial name | ||||||||||||||
| Juglans californica S. Wats. |
Juglans californica, the California Black Walnut, also called the California Walnut, or the Southern California Black Walnut, is a large shrub or small tree endemic to California. There are two known varieties (according to the The Jepson Manual) or subspecies (according to the California Native Plant Society). This article uses the The Jepson Manual convention of varieties, Juglans californica var. californica (Southern California Black Walnut), and Juglans californica var. hindsii Jeps. (Northern California Black Walnut). Note that in this case a common name used for the species, Southern California Black Walnut, is also a common name for one of the varieties.
The California black walnut can be either a large shrub with 1-5 trunks, or a small single-trunked tree. The main trunk can fork close to the ground making it look like two trees that have grown together, then diverged. It can grow as tall as 25m and has thick bark, deeply channeled or furrowed at maturity. It has large, pinnately compound leaves with 11-19 lanceolate leaflets with toothed margins. It has a small hard nut in a shell that is difficult to remove. The Chumash Indians of the Channel Islands of California eat the nuts, however, they are not grown commercially for this purpose.
The Northern California black walnut is commercially important as a rootstock for English walnut orchards all over the world, both on its own and as a parent to the J. hindsii x J. regia 'Paradox' hybrid. In the walnut industry the Northern California black walnut variety is usually called Juglans hindsii, and the Southern California black walnut is called Juglans californica. The Northern California variety is endangered, with possibly only a few native stands remaining. The Southern California variety is threatened by development and overgrazing, although there are far more native stands remaining, including some in urban Los Angeles.
The California black walnut grows in riparian woodlands, either in single species stands or mixed with California's oaks (Quercus) and cottonwoods (Populus). It grows as part of mixed woodlands in California's Coast Ranges, Transverse Ranges, and Peninsular Ranges, and also on slopes and in valleys wherever conditions favor it throughout California west of the Sierra Nevada and the deserts and south of the Klamath Mountains. It is cultivated as an ornamental tree wherever it will grow in California, and in Hawaii.
[edit] References
- Hickman, James C., ed. The Jepson Manual: Higher Plants of California. University of California Press. 1993.
- Anderson, E. N. "Some preliminary observations on the California black walnut (Juglans californica)" in Fremontia: A Journal of the California Native Plant Society. January 2002.
