California Adolphia [Adolphia californica Wats.]
Listing CNPS List 2 R-E-D Code 1-2-1
State/Federal. Status -- None RHAMNACEAE Dec.-Apr.
Global Rank G3 State Rank S2.1
Distribution: Coastal San Diego County; Baja California, Mexico
Habitat: This short shrub is often intermixed with Diegan Sage Scrub, but occasionally occurs in peripheral chaparral habitats, particularly hillsides near creeks. The California Adolphia (sometimes called California Spinebush) is usually associated with Eriogonum fasciculatum and Artemisia californica in xeric locales where shrub canopy reaches four or five feet in height. During late summer and fall it may be virtually leafless, and therefore not apparent from a distance; however, its spiny stems are readily noted at close range. The San Miguel and Friant soils are both quite amenable to California Adolphia.
Known Sites: California Adolphia is still found at a variety of coastal San Diego County locales. Substantial populations occur south of Del Dios Highway and 1 mile southwest of Lake Hodges Dam on steep north-facing slopes, and on south-facing slopes of Escondido Creek east of Lake Val Soreno. A very extensive colony with over 1000 shrubs was found in 1990 near the Inspiration Point Cross north of the Questhaven Retreat. One of the largest sites noted is a football field sized colony almost entirely composed of Adolphia upstream of the Sweetwater Reservoir, south of the old wooden bridge, on the south side of the river. Several thousand are found across the river and just upstream where they are a dominant element within the sage scrub. Scattered sites are in the hills south of the Sweetwater Reservoir and on the flanks of Mother Miguel Mountain. Another large population occurs on a west-facing slope east of Saxony Road near Batiquitos Lagoon. This shrub was noted in limited numbers at numerous other surveyed sites including the finger canyon east of Dillon Road on southern Otay Mesa, at scattered locales in Otay Valley east of the Interstate 805, in the sage scrub north of Lower Otay Lake, below Sweetwater Dam, a hillside west of Lake Murray Dam, on the southwestern flanks of Black Mountain near Rancho Penasquitos, along San Marcos Creek below San Marcos Dam, west of Melrose Drive and south of Shadowridge Drive in Vista, and on north-facing slopes of Peñasquitos Canyon just south of the water treatment plant near Poway. Small populations were seen near Akita Lane in Rancho Santa Fe, at the eastern terminus of Rosemont Street in La Jolla, near the Fairbanks Country Club south of San Dieguito Road, south of Aliso Canyon Road near Rancho Santa Fe, on the Green Oaks Ranch at Agua Hedionda Creek, on canyon slopes west of Black Mountain Road and north of Peñasquitos Canyon, on the eastern boundary of Fairbanks Ranch, near Mercy Road east of Interstate 15, and near the intersection of Poinsettia Avenue and Palomar Airport Road. Also, old reports on the periphery of its known range are near southern Camp Pendleton at Moro Hill, as well as to the southeast of most reports near Barrett Junction. Old Biological survey reports note sites, northwest of Lake Hodges Dam, near Lake Calavera, west of the Olivenhain Cemetery, on Rancho Aqua Hedionda Y Los Manos near Aqua Hedionda Creek, near El Apajo Road just south and beyond the Rancho San Dieguito boundary, 0.5 mile north of La Zanja Canyon and 1 mile east of San Dieguito Valley, southwest of Sienna Canyon Drive in Encinitas, Sundance Mountain near Carmel Mountain Drive, between Evans Point and Letterbox Canyon, and near the intersection of Fairmont and Montezuma Roads in the vicinity of San Diego State University. Data Base records are from the Otay River near the mouth of Johnson Canyon, northeast of Agua Hedionda Lagoon west of El Camino Real Road between Skyline Road and Neblina Drive, 2 miles north of San Marcos Creek and east of El Camino Real to the north of the golf course, 2 miles east of the San Dieguito Reservoir and 0.6 mile south of the San Dieguito River north of a dammed pond, the Kelly Ranch about 1.1 mile south of Calavera Lake in Carlsbad, 0.8 mile south of Highway 78 and 0.9 mile east of El Camino Real in Carlsbad, between Interstate 15 and Black Mountain Road 0.5 mile north of Mira Mesa Boulevard, adjacent to Interstate 15 and Chicarita Creek from 1.0 to 1.7 miles north of Poway Road and to the northeast, southwest flank of Paint Mountain near Rancho Santa Fe, north of confluence of Lusardi Creek and San Dieguito River east of Rancho Santa Fe, north of Artesian Road and 1.5 miles south of the San Dieguito River, 1 mile east of the San Dieguito Reservoir, 1 mile from San Diego State University near the western corner of Yerba Santa Drive and Montezuma Road, one block south of Mission Gorge Road near Margerum Avenue, Alvarado Canyon 0.5 mile southwest of Lake Murray, on Black Mountain Road about 0.4 mile northeast of 4-S Ranch and 0.5 mile east of Artesian Road, the east slope of Battle Mountain, north and south of Paco Lago Road and west of Via Abertura Road near Fairbanks Ranch, north of Manchester overlooking the San Elijo Lagoon, Lux Canyon in Encinitas, southwest side of Evans Point Headland near Agua Hedionda Lagoon, just south of Encinitas Road about 400 yards from the junction with Linda Vista Road, Lopez Ridge, south of Lake Hodges and 2.5 miles west of Battle Mountain, northern tributary canyons of La Jolla Valley on the 4-S Ranch 3.5-4.5 miles south of Lake Hodges, 1.2 miles north of San Marcos Creek between El Camino Real and Unicornio Street, 1.2 and 1.8 and 2.1 miles southwest of Lake San Marcos Dam near Santa Fe Road realignment, north of San Marcos Creek and 0.3 mile south of Alga Road, San Marcos Creek near Rancho de los Quiotes, 0.5 mile west of San Francisco Peak and 0.4 mile northeast of Cerro de la Calavera, Evans Point east to approximately 0.5 mile west of Mount Hinton, near Carlsbad 0.5 mile south of Mount Hinton, southwest of Mount Hinton near the intersection of Palomar Airport Road and El Camino Real, west side of Green Valley on the Ecke Ranch 0.6 mile southwest of intersection of La Costa Avenue and El Camino Real, 2 miles north of intersection of Encinitas Boulevard with Manchester Avenue and 1 mile east of El Camino Real, 1 mile southeast of La Costa Country Club east of Green Valley, north of Batiquitos Lagoon and 1.2 miles northwest of La Costa Country Club, Batiquitos Lagoon approximately 1 mile northeast of the intersection of Interstate 5 and La Costa Avenue, 0.25 mile west of intersection of El Camino Real and Arenal Road, north of bend on Lusardi Creek approximately 2-2.5 km from confluence with San Dieguito River, 1 km south southeast of confluence of Lusardi Creek and San Dieguito River, south of La Jolla Valley and 4.8 km due south of Lake Hodges Dam, near Carmel Mountain, and a number of locales northeast and northwest of intersection of Black Mountain Road and McGonigle Road on Black Mountain Ranch.
Collected south in Baja California to 30 6' North by Moran (SD 87216) at Sauzalito-2. Lightly collected in Baja with 14 specimens deposited in the San Diego Natural History Museum's herbarium.
Status: California Adolphia is substantially declining due to urban growth; still healthy populations are extant. This spiny shrub is sometimes a dominant shrub on hillsides, and such sites should be protected. Although Adolphia is not uncommon in southwestern San Diego County, a decade of continued urbanization along the coast could significantly reduce the populations now extant. California Adolphia should be considered for native revegetation projects in suitable habitat.
Copyright © May 1994 Craig H. Reiser.