294 FOREST TREES OF THE PACIFIC SLOPE. 



crevices and send up sprouts year after year, provided that the thin stems are 

 not too severely burned. 



Longevity. — Not fully determined. A single stem 4J inches through shows an 

 age of 20 years. 



RANGE. 



Central California to Lower California. Chaparral belt of foothills from central 

 Sierras and of coast ranges in Mendocino County and Trinity Mountains, southward to 

 northern Lower California ; also on islands off southern California, here, only, becoming 

 a tree of any considerable size. 



California. — Common scrub oak of southern coast ranges, the type definitely known 

 northward on seaward mountains only to San Mateo County, and on Mount Hamilton 

 range to southern Alameda County ; eastward in southern California to desert slopes of 

 San Gabriel, San Bernardino, San Jacinto, and Cuyamaca mountains. Common in Santa 

 Lucia and San Luis Obispo mountains between 1,000 and 4,000 feet elevation, in Sur, 

 Carmelo, Arroyo Seco, San Antonio, Nacimiento, Carriso, Salinas, Santa Margarita, 

 San Luis. Arroyo Grande, and Huasna river basins. In central Sierras the species is 

 often more common than its variety revoluta. Locally noted in Butte County on foot- 

 hills along Chico-Sterling Road; foothills on Sweetwater Creek (Eldorado County) ; in 

 Stanislaus National Forest, forming small thickets near bottoms of canyons at 2,500 

 to 3.000 feet, on headwaters of Esperanza Creek (tributary North Fork Calaveras River), 

 and on San Antonio and Indian Creek (tributaries of South Fork of latter river) ; also 

 at Sherlock and West Point. In Sierra National Forest, reported on canyon sides of 

 East Fork of Tule River, below Nelson's ranch, at about 5.500 feet elevation and on 

 Greenhorn Mountains up to 5.000 feet. Very abundant in southern mountains. Its 

 lowest altitude in Santa Barbara National Forest is 1.400 feet, while it goes up to 5,000 

 and sometimes 7,000 feet ; in watersheds of Santa Maria, Santa Ynez, Santa Barbara, 

 Matilija, Firu-Sespe, Newhall, and Elizabeth rivers. In San Gabriel Mountains, on south 

 and north slopes facing desert, growing on foothills south of Antelope Valley (western 

 extremity of Mojave Desert), and on Liebre ranch ; abundant on both sides of Cajon Pass, 

 and farther west, at west end of Antelope Valley, common on hillsides facing desert ; 

 thence southward through Canada de las Uvas. In San Bernardino Mountains east- 

 ward to canyons facing desert. Abundant in chaparral belt of San Jacinto National 

 Forest up to 5,000 feet on mountain sides, and often among pines at higher elevations 

 on south side. On Santa Ana Mountains, nearer coast, in scrub growth on tops of range 

 at 1,600 feet. Occurs in San Diego County on mountains from near sea (Temecula 

 Canyon, near San Diego, and near mouth of Tia Juana River, on Mexican boundary) 

 eastward to Coast Range ; here, in Palomar, Balkan, and Cuyamaca mountains, reaching 

 east slopes ; on Mexican boundary, down to about 2,543 feet on east slope, at Wagon Pass, 

 going to about 4,000 feet, and at Jucumba Hot Springs down to 2.S22 feet elevation. 



The form a in Santa Cruz and Santa Rosa islands, off the southern mainland coast, 

 usually with rather large lobed leaves, is exceptional in representing the principal tree 

 growth of this species. Its size and larger foliage are believed, however, to result from 

 its protected habitat in these island canyons. 



Loweb California. — Southward on foothills of Mount San Pedro Martir to Telmo, 

 about latitude- 31°. 



The range of Quercus dumosa revoluta, which is within that of the species, is imper- 

 fectly known. Foothills of central Sierras and of coast ranges chiefly north of San 

 Francisco Bay. In Sierras recorded only from Stanislaus National Forest, where it 

 forms occasional dense thickets ; locally noted near Volcanoville and Georgetown. Occurs 

 rarely in Coast Mountains southward to Santa Lucia Mountains, but replaces species 

 apparently only north of San Francisco Bay ; abundant to Mendocino County and Napa 

 Valley, and probably with species in Stony Creek National Forest, north of Clear Lake, 

 and in Trinity Mountains (Shasta National Forest) ; locally noted in Lake County, 

 Knoxville Grade, Napa River Basin, and in Upper Conn Valley. 



OCCURRENCE. 



Low mountain and foothill slopes and sides of desert hill canyons, in the poorest 

 and driest gravelly soils, often so sterile as to support little else. 



In scattered, thick clumps and patches of pure growth, more or less interspersed with 

 Christmas berry, mountain mahogany, ceanothus brush, manzanitas and other chaparral, 

 of which it is essentially a part. 



Climatic Conditions.— Similar to those of gray pine. 



Quercus macdonaldi Greene. 



