30 CALIFORNIA VEGETABLES. 



as you proceed southward. Take an instance of specializ- 

 ing production : Humboldt, Mendocino and Sonoma coun- 

 ties, coast side, low temperature and large rainfall, known 

 from the earliest times as a great potato country; San 

 Luis Obispo, Santa Barbara and Ventura counties, coast 

 side, higher temperatures and light rainfall, producing 

 a considerable part of all the beans grown in the State. 

 And yet though these differences thus notably localize 

 production, the whole coast region north and south has 

 this in common ; it has a more equable and lower tempera- 

 ture and a more generous rainfall than the interior valley 

 at its own latitude ; it also has lighter frosts, growing 

 lighter still toward the south until it incloses regions here 

 and there which favoring topography makes practically 

 frostless. Such situations favor all-the-year growth of the 

 tenderest vegetables, and perennial beans and tomato 

 trees are possible. 



Interior Lowlands. A region which has recently greatly 

 advanced in importance in vegetable production comprises 

 the lower lands of the interior valleys. They lie along 

 the two great rivers of the northern and central parts of 

 California the Sacramento and San Joaquin, and their 

 tributaries. These rivers flow from nearly two hundred 

 miles, north and south of their confluence, where they 

 mingle their waters through numerous sloughs until the 

 joint streams pour through a gap in the coast range into 

 San Francisco bay. The same gap which lets out the 

 waters lets in the ocean current of moisture-laden wind 

 and moderates the heat of the entire interior valley, but 

 naturally dispenses most moisture and coolness over the 

 lowlands which lie just in its course as it rushes north- 

 ward and southward to displace the air which is rarified 

 by the sun heat on the interior plains of the great valley. 

 These interior lowlands along the lower stretches of the 

 rivers have then an interior climate modified by the in- 

 trusion from the coast, but this only acts in full measure 

 during June, July and August. It serves, therefore, as a 



