Nuttall's Scrub Oak [Quercus dumosa Nutt. in part]

Nuttall's Scrub Oak [Quercus dumosa Nutt. in part]

Listing CNPS List 1B R-E-D Code 2-3-2

State/Federal. Status -- /C2 FAGACEAE Feb.-Mar.

Global Rank G2 State Rank S1.1

Distribution: San Diego County, Orange County, Santa Barbara County; Baja California, Mexico

Habitat: Coastal chaparral with a relatively open canopy cover is the preferred habitat in flat terrain; on north-facing slopes this shrub may grow in dense stands. Chesterton fine sandy loams are mapped for the Miramar Naval Airbase population. This coastal shrub is considered by a number of recent taxonomists to represent a distinct species (as opposed to the common inland shrub referred to Quercus berberidifolia). It often has a rounded, almost "pruned" aspect which is quite different than the more erect growing, inland shrub. In addition, the leaves tend to be smaller, more spinose, and quite undulate.

Known Sites: This coastal scrub oak occurs at a variety of locales such as Point Loma and Torrey Pines State Park along the immediate coast. Occasionally it occurs inland such as on the Miramar Naval Airbase where it grows in considerable numbers, in the hills at Camp Elliott, and on the northwestern slopes of Otay Mesa. A characteristic, low-growing colony is found on the peak east of Interstate 15 and south of Poway Road. Numerous populations are now isolated in the urban canyons of San Diego City neighborhoods such as Linda Vista and Clairemont (e.g., west of Mesa Junior College). This oak is locally common near Del Mar Heights Road and east of Torrey Pines High School, nearby south of Del Mar Road and east of El Camino Real, as well as on north-facing slopes north of El Nido road in Rancho Santa Fe. Herbarium specimens examined from San Diego County include sites in Mission Valley, on Kearny Mesa, near La Cencilla and Skyline Drive in Rancho Santa Fe, Soledad Mountain, and near the University of California at San Diego campus. One bush grows at Dana Point in Orange County, and a sizeable colony grows adjacent to Pacific Island Drive in Laguna Niguel. Also reported by Roberts for Orange County at in Aliso-Wood Canyon Regional Park and nearby Los Truncos Canyon.

Three voucher specimens from Baja California are found in the herbarium of the San Diego Natural History Museum; south to 31 12' North at San Antonio de la Mesa where collected by Moran (SD 64723).

Status: Coast Scrub Oak is substantially declining in San Diego County due to urban expansion along the coast. Taxonomic work is necessary to determine the frequency of intergradation between this species and the common Quercus berberidifolia. Obvious hybrids between the Coast Scrub Oak and Quercus engelmannii are found at a number of locales in coastal San Diego County. Sizeable portions of larger populations are recommended for protection.


Copyright May 1994 Craig H. Reiser.

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