116 THE BROAD-SCLEROPHYLL VEGETATION OF CALIFORNIA. 



List II. — Obligate Shrubs. 

 BETULACEjE. 



16. Corylus rostrata Ait. var. californica A. DC. Hazelnut. Central and northern 

 Coast Ranges and Sierra Nevada. A rather unimportant constituent of the conifer-forest 

 chaparral; occurs more commonly as undergrowth in mesophytic forest. Deciduous. 1 



17. Castanopsis sempervirens (Kellogg) Dudley. Golden chinquapin. From the south- 

 ern Cascades along the Sierras, southward to Mount San Jacinto. Characteristic of the 

 conifer-forest chaparral of the higher altitudes. 



18. Quercus breweri Engelm. Brewer oak. Inner Coast Ranges from Mount Yolo 

 Bolly north; Sierra Nevada to the Kern River region. Forms extensive thickets at middle 

 altitudes. A member of the conifer-forest chaparral. Deciduous. 



19. Quercus dumosa Nutt. Scrub oak. From the region of Mount Shasta to Lower 

 California (lat. 31°); on the Coast Ranges and Sierra Nevada. Most abundant in the 

 coastal region of southern California. A very important member of the climax chaparral, 

 ranking with certain species of Arctostaphylos and Ceanothus, next to Adenostoma. Barely 

 evergreen. 



20. Quercus durata Jepson. Scrub oak. Closely related to the last. Range not satis- 

 factorily determined, but apparently covering the middle Coast Ranges from the Santa 

 Lucia Mountains north to Mendocino County and the Napa Range, and probably to the 

 Trinity Mountains. Reported from Stanislaus National Forest in the Sierra Nevada. 

 Similar in status to the last. 



21. Quercus sadleriana R. Br. Confined to the mountains of southwestern Oregon and 

 northwestern California. Forms pure thickets, probably successional. Barely evergreen. 



22. Quercus vaccinifolia Kellogg. Huckleberry oak. Inner north Coast Ranges from 

 Mount Shasta to Trinity County; throughout the higher forest region of the Sierra Nevada. 

 A member of the conifer-forest chaparral; also occurring as undergrowth in the subalpine 



TOT*PSts 



BERBERIDACE^l. 



23. Berberis pinnata Lag. California barberry. Central Coast Ranges. Sometimes 

 in the chaparral; occasionally in the oak forests. Unimportant. 



PAPAVERACEjE. 



24. Dendromecon rigidum Benth. Bush poppy. Of general distribution; from Shasta 

 National Forest southward through Coast Ranges and Sierras, reaching Mount San Pedro 

 Martir in Lower California; records scarce north of Sonoma and Napa Counties. A 

 widely distributed and characteristic member of the climax chaparral, though nowhere 

 abundant; its bright yellow flowers contribute a pleasing touch of color here and there. 



ROSACEA. 



25. Heteromeles arbutifolia (Poir.) Roem. Christmas berry; California holly; tollon 

 (pronounced "toyon"). Coast Ranges and Sierra Nevada, and through southern Califor- 

 nia and Lower California to the Cape region. A characteristic member of the climax 

 chaparral; not often abundant, but seemingly so because of its fine clusters of red berries 

 and because it usually overtops its neighbors. Sometimes attains tree stature, but retains 

 its shrub form. More tolerant of shade than most of its chaparral companions; therefore 

 frequently found in the oak forest. 



26. Arnelanchier alnifolia Nutt. Service berry. Has the widest distribution of all the 

 species occurring in the chaparral, ranging from Alaska to Mount San Pedro Martir in 

 Lower California, east to Michigan, Nebraska, Colorado, and New Mexico; in California 

 occurring in the Coast Ranges from San Francisco Bay northward, in the Sierras and the 

 higher mountains of southern California. A rather frequent member of the conifer-forest 

 chaparral. Deciduous. 



27. Cercocarpus betuloefolius Nutt. Birch-leaf mahogany. Throughout the foothills 

 and lower mountains of California. A common and frequently abundant member of the 

 climax chaparral, especially in the more mesophytic situations. Often gregarious on north 

 slopes, the groups in seed time showing from a distance as white patches. 



1 Unless otherwise'notcd, species are evergreen in leaf habit. 



