142 OUTLINE OF PLANT GEOGRAPHY 



Inside the coast ranges are many valleys, great and small, by 

 far the most important being the great central valley drained by 

 the Sacramento and San Joaquin rivers which unite and discharge 

 into the Bay of San Francisco. This great valley is a vast plain 

 some 400 miles long, and over 50 miles wide in places. Much of 

 this is treeless, recalling the mid-western prairies, and is a region 

 of great fertility, which under irrigation has become very produc- 

 tive. Numerous smaller valleys, also highly fertile, occur in both 

 northern and southern California. 



The valleys and foot-hills are largely covered with annual 

 grasses, which die at the beginning of the long diy summer, this 

 being the period when much of the native vegetation is dormant. 

 As soon as the first heavy rains come, usually in October or No- 

 vember, the grass-seeds quickly germinate, as well as those of 

 many other annuals, native and introduced, and the landscape 

 changes from brown to vivid green, to last through the winter and 



spring. 



The annual grasses which are so abundant in the valleys of 

 California, are mostly species introduced from southern Europe. 

 The most conspicuous of these is the wild oat (Avena fatua) , which 

 is very common, and furnishes valuable forage. The native grasses 

 are mostly perennial bunch-grasses, e. g., Stipa spp., Danthonia 

 spp., Bouteloua spp. 



There is a great variety of showy annuals which in favorable 

 seasons cover the hillsides and meadows with masses of splendid 

 color. Many of these are familiar in cultivation, e. g., Nemophila, 

 Gilia, Eschscholtzia, Phacelia, Lupinus, Godetia, Clarkia, etc., 

 but there are many others, especially such showy Compositae as 

 Layia, Baeria, and others like Orthocarpus, which are not so well 

 known. Perhaps the showiest of all, and almost the commonest, 

 is the California poppy, Eschscholtzia Californica, which forms 

 solid masses of blazing orange sometimes acres in extent, and often 

 associated with patches of brilliant blue lupins, almost as showy, 

 and produced in equal profusion. 



With the annuals are associated a number of perennials, largely 

 tuberous or bulbous species. Buttercups, mallows (Sidalcea), 

 a large yellow composite (Wyethia), various Umbelliferae, and 

 especially a variety of liliaceous species, as well as species of Iris 

 and Sisyrynchium. 



