Taxon Report

Juglans californica Wats.

Southern California black walnut

Print Report

© 2020 Zoya Akulova

Classification


Scientific Name:	Juglans californica Wats.
Common Name:	Southern California black walnut
Family:	Juglandaceae
Element Code:	PDJUG02020
USDA Plants Symbol:	JUCA
Synonyms/Other Names:	Juglans californica Wats. var. californica

Ecology and Life History


Lifeform:	perennial deciduous tree
Blooming Period: Mar-Aug	Mar-Aug
Elevation:	50-900 (165-2955)
General Habitats:	Chaparral, Cismontane woodland, Coastal scrub, Riparian woodland
Microhabitat:
Microhabitat Details:	alluvial

Conservation Status


CA Rare Plant Rank:	4.2
Global Rank:	G4
State Rank:	S4
State List:	None
Fed List:	None
Other Status:	IUCN_NT; SB_CalBG/RSABG; SB_USDA
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	0
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	0
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	0

Location


California Endemic: True
California Counties and Islands: Name (Code)
Fresno (FRE), Kern (KRN), Los Angeles (LAX), Orange (ORA), Riverside (RIV), San Bernardino (SBD), San Diego (SDG), Santa Barbara (SBA), Santa Clara (SCL), Ventura (VEN)
Quads: Name (Quad Code)
Acton (3411842), Alamo Mountain (3411868), Alberhill (3311764), Alpine (3211677), Anaheim (3311778), Azusa (3411728), Bachelor Mtn. (3311751), Bald Mountain (3411978), Baldwin Park (3411718), Beaumont (3311688), Beverly Hills (3411814), Black Mtn. (3411867), Black Star Canyon (3311776), Blackburn Canyon (3311667), Bonsall (3311732), Borrego Palm Canyon (3311634), Burbank (3411823), Cabazon (3311687), Cajon (3411734), Calabasas (3411826), Camarillo (3411921), Canada Gobernadora (3311755), Canoga Park (3411825), Carpinteria (3411945), Casmalia (3412075), Cobblestone Mtn. (3411857), Condor Peak (3411832), Corona North (3311785), Corona South (3311775), Crystal Lake (3411737), Cucamonga Peak (3411725), Del Mar (3211782), Devils Heart Peak (3411858), Devore (3411724), Dulzura (3211667), Eagle Rest Peak (3411982), Earthquake Valley (3311614), El Cajon (3211678), El Cajon Mtn. (3211687), El Casco (3311781), El Monte (3411811), El Toro (3311766), Encinitas (3311713), Fallbrook (3311743), Fillmore (3411848), Fontana (3411714), Forest Falls (3411618), Glendora (3411727), Goleta (3411947), Green Valley (3411854), Guasti (3411715), Hollywood (3411813), Jamul Mountains (3211668), Julian (3311615), La Habra (3311788), Laguna Beach (3311757), Lake Elsinore (3311763), Lake Mathews (3311774), Lion Canyon (3411952), Lompoc Hills (3412054), Los Alamos (3412063), Los Angeles (3411812), Malibu Beach (3411816), Matilija (3411943), Mint Canyon (3411844), Moorpark (3411838), Mount San Antonio (3411736), Mt. Baldy (3411726), Mt. Wilson (3411821), Murrieta (3311752), Newbury Park (3411828), Newhall (3411845), Oat Mountain (3411835), Ojai (3411942), Old Man Mountain (3411954), Ontario (3411716), Orange (3311777), Orcutt (3412074), Pala (3311731), Pasadena (3411822), Piru (3411847), Pitas Point (3411934), Point Conception (3412044), Point Dume (3411817), Point Mugu (3411911), Prado Dam (3311786), Rancho Nuevo Creek (3411964), Rancho Santa Fe (3311712), Redlands (3411712), Riverside East (3311783), Riverside West (3311784), Rodriquez Mtn. (3311628), Romoland (3311762), San Bernardino North (3411723), San Bernardino South (3411713), San Dimas (3411717), San Fernando (3411834), San Pasqual (3311618), Santa Barbara (3411946), Santa Paula (3411931), Santa Paula Peak (3411941), Santa Rosa Hills (3412053), Santa Susana (3411836), Santa Ynez (3412051), Santiago Peak (3311765), Saticoy (3411932), Silverwood Lake (3411733), Simi (3411837), Sitton Peak (3311754), Solvang (3412052), Sunland (3411833), Sunnymead (3311782), Telegraph Peak (3411735), Temecula (3311742), Thousand Oaks (3411827), Topanga (3411815), Torrance (3311873), Tranquillon Mtn. (3412055), Triunfo Pass (3411818), Tubb Canyon (3311624), Val Verde (3411846), Valyermo (3411747), Van Nuys (3411824), Ventura (3411933), Viejas Mountain (3211676), Warm Springs Mountain (3411855), Waterman Mtn. (3411738), Wheeler Springs (3411953), Whitaker Peak (3411856), White Ledge Peak (3411944), Whittier (3311881), Wildomar (3311753), Winchester (3311761), Yorba Linda (3311787), Yucaipa (3411711)

Threat List Data from the CNDDB


Threat List Total:	0
EOs with Threat Listed:	Total EOs	% of EOs
	0	0 %

Notes



Walnut forest is a much fragmented, rare, and declining vegetation community. Threatened by urbanization, grazing, non-native plants, and possibly by lack of natural reproduction. Possibly threatened by hybridization with horticultural varieties of walnut. A synonym of J. californica var. californica in The Jepson Manual. See Proceedings of the American Academy of Arts and Sciences 10:349 (1875) for original description, and Southern California Botanists Special Publication No. 3, pp. 42-54 (1990) for additional information.
Threats:

Taxonomy:

Selected References

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 9 January 2025].