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California Blackwalnut

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Eudicots
Cladus: Core eudicots
Cladus: Rosids
Cladus: Eurosids I
Ordo: Fagales

Familia: Juglandaceae
Subfamilia: Juglandoideae
Genus: Juglans
Species: Juglans californica

Juglans californica S.Watson, 1875
Native distribution areas:

Continental: Northern America
Regional: Southwestern USA
SW. California.
Introduced into:
North Caucasus, Tadzhikistan, Transcaucasu

References: Brummitt, R.K. 2001. TDWG – World Geographical Scheme for Recording Plant Distributions, 2nd Edition
Primary references

Watson, S., 1875. Proceedings of the American Academy of Arts and Sciences. Boston, MA 10:349.

Additional references

Flora of North America Editorial Committee (1997). Flora of North America North of Mexico 3: 1-590. Oxford University Press, New York, Oxford.


Govaerts, R. et al. 2022. Juglans californica in Kew Science Plants of the World online. The Board of Trustees of the Royal Botanic Gardens, Kew. Published online. Accessed: 2022 Mar 02. Reference page.
Hassler, M. 2022. Juglans californica. World Plants: Synonymic Checklists of the Vascular Plants of the World In: Roskovh, Y., Abucay, L., Orrell, T., Nicolson, D., Bailly, N., Kirk, P., Bourgoin, T., DeWalt, R.E., Decock, W., De Wever, A., Nieukerken, E. van, Zarucchi, J. & Penev, L., eds. 2022. Species 2000 & ITIS Catalogue of Life. Published online. Accessed: 2022 Mar 02. Reference page. 2022. Juglans californica. Missouri Botanical Garden. Published online. Accessed: 02 Mar 2022.
International Plant Names Index. 2022. Juglans californica. Published online. Accessed: Mar 02 2022.
USDA, ARS, Germplasm Resources Information Network. Juglans californica in the Germplasm Resources Information Network (GRIN), U.S. Department of Agriculture Agricultural Research Service. Accessed: 2022 Mar 02.

Vernacular names
English: California Walnut
українська: Горіх каліфорнійський

Juglans californica, the California black walnut, also called the California walnut, or the Southern California black walnut,[1] is a large shrub or small tree (about 20-49[3] feet tall) of the walnut family, Juglandaceae, endemic to Southern California.


Juglans californica is generally found in the southern California Coast Ranges, Transverse Ranges, and Peninsular Ranges. It grows as part of mixed woodlands, and also on slopes and in valleys wherever conditions are favorable. It is threatened by development and overgrazing.[1] Some native stands remain in urban Los Angeles in the Santa Monica Mountains and Hollywood Hills. J. californica grows in riparian woodlands, either in single species stands or mixed with California's oaks (Quercus spp.) and cottonwoods (Populus fremontii).

Juglans californica 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 has thick bark, deeply channeled or furrowed at maturity. It has large, pinnately compound leaves with 11–19 lanceolate leaflets with toothed margins and no hair in the vein angles.[4] It has a small hard nut in a shallowly grooved, thick shell that is difficult to remove.

The nuts are edible[5] and were eaten by the Chumash Indians of the Channel Islands of California and Ventura County . They are not grown commercially as food.

Juglans californica is cultivated throughout California to support the walnut industry, used as a rootstock in English walnut orchards. It is also cultivated as an ornamental tree where it is planted in California native plant, xeriscape, and wildlife habitat gardens and natural landscaping in California, and in Hawaii.

Some authorities (e.g. the California Native Plant Society) combine this species with Juglans hindsii. On the other hand, a 2007 molecular analysis of the genus[6] suggests J. californica is sister to the remaining black walnuts (section Rhysocaryon). This article follows the conventions of The Jepson Manual.[7][8]

Stritch, L.; Barstow, M. (2019). "Juglans californica". IUCN Red List of Threatened Species. 2019: e.T35154A61524825. doi:10.2305/IUCN.UK.2019-2.RLTS.T35154A61524825.en. Retrieved 19 November 2021.
Essa, Lora. "Index of Species Information". U.S. Department of Agriculture, Forest Service. Retrieved 2013. {{cite web}}: Check date values in: |accessdate= (help)
"California Black Walnut Trees | City of Walnut, CA". Retrieved 2019-10-17.
Kershner, Mathews, Nelson, and Spellenberg, National Wildlife Federation field Guide to Trees of North America, 2008, Chanticleer Press, Inc. p. 229
Elias, Thomas S.; Dykeman, Peter A. (2009) [1982]. Edible Wild Plants: A North American Field Guide to Over 200 Natural Foods. New York: Sterling. p. 247. ISBN 978-1-4027-6715-9. OCLC 244766414.
Aradhya, M. K, D. Potter, F. Gao, & C. J. Simon: "Molecular phylogeny of Juglans (Juglandaceae): a biogeographic perspective: Tree Genetics & Genomes (2007)3:363–378
Juglans californica S. Watson var. hindsii Jeps.

Juglans hindsii Jeps. ex R. E. Sm.

Further reading

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.

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