140 OUTLINE OF PLANT GEOGRAPHY 



apparently requiring the protection of the fog-blanket against 

 the hot sun of the rainless summer. In the mixed redwood forest 

 of central California there are several characteristic broad-leaved 

 evergreen trees. The tan-bark oak and madrono have already 

 been mentioned and in addition to these are the mountain live 

 oak (Qvsrcus chry sole pis), an evergreen chestnut (Castanopsis), 

 and the beautiful bay-tree (Umbellularia). Black oak (Quercus 

 Kelloggii) and the big-leaved maple, are the most important 

 deciduous trees, but along the streams are large alders, cotton- 

 woods, willows, and the box-elder {Acer Negundo). 



A dwarf yew (Taxus brevifolia) and the " nutmeg" {Torreya 

 Calif arnica), also of the yew family, are sometimes found in the 

 redwood forest. Torreya has its only other American representa- 

 tive in Florida. 



Of the attractive shrubs of the redwood forest, the most beauti- 

 ful are the pink rhododendron {R. Calif or nicum), and the azalea 

 {R. occidentale) . The former is mainly confined to the north, and 

 is restricted to the coastal region, while the azalea has a wider 

 distribution. Evergreen huckleberries and barberries are abun- 

 dant, and the big white-flowered thimble-berry {Rubus Nutkanus), 

 pink-flowered currants, blackberries, Spiraea, and roses, are 

 characteristic. 



Among the common woodland flowers are Trillium, Ery- 

 thronium, Fritillaria, Clint onia, violets and cress (Cardamine, 

 Dentaria), Smilacina, Aquilegia, Cynoglossum, Delphinium and 

 many others. Ferns are abundant, but there is no great variety. 

 Adiantum pedatum, Woodwardia Chamissoi, Aspidium munitum, 

 are perhaps the most striking. 



Central California is a meeting place for the northern and south- 

 ern floras. This is very well shown in the region about Stanford 

 University in the Santa Clara Valley, about thirty miles south 

 of San Francisco. To the west are the Santa Cruz mountains, 

 the highest points rising about 3,000 feet above the valley. The 

 sheltered valleys, which are accessible to the sea-fogs, have a fine 

 growth of redwoods, some of great size, and with them are the 

 usual associates, Douglas fir, tan-bark oak, madrono, laurel, etc. 



These mountains, all through the summer, get the ocean fogs 

 which drift into the redwood canyons, but rarely reach the valley 

 floor, except occasionally as "high fog." 



