124 THE DATE PALM. 



the Sacramento and San Joaquin rivers. The climate is here very 

 different from that of the other regions mentioned above, especially in 

 the much heavier rainfall, which in many places is sufficient to permit 

 the date palm to grow without irrigation. As a result of this more 

 humid climate there is more danger of damage to the flowers in spring, 

 and especially more risk of losing the ripening fruit in autumn, in 

 consequence of a spell of wet weather. The summer season is nearly 

 or quite rainless; otherwise date culture would be impossible. 



As a result of investigations on the life history of the date palm, it 

 is evident that only the very early sorts can mature their fruit in this 

 region, owing to the insufficient summer heat. These earliest vari- 

 eties, though often a very palatable fruit, suitable for home consump- 

 tion, are as a rule unfit for drying and for export. Experiments are 

 now under way in cooperation with the California Experiment Station 

 which will decide in a few years whether any of the early Saharan, 

 Egyptian, and Arabian sorts suitable for drying can mature in this 

 region. 



All parts of the San Joaquin and Sacramento River valleys offer 

 about equal advantages for date culture, except in the region where the 

 two rivers unite. This section lies directly east and northeast of San 

 Pablo and Suisun bays, and the cold winds which blow in from the 

 Pacific over San Francisco Bay find their way eastward through this 

 break in the coast range, and thus lower the summer temperature; it is 

 unlikely that any dates can be ripened in this area, which extends 

 from Stockton to Sacramento and across the valley to the foothills. 



The winters are mild enough in most parts of the interior valley 

 region to permit date palms to grow without injury, provided they are 

 protected when young. In some of the colder localities only hardy 

 sorts will succeed, and at Tulare it has been found by the California 

 Experiment Station that several of the Egyptian sorts imported in 

 1889 by the Department of Agriculture are severely injured by 

 freezes in winter, especially if by late irrigation the palms had been 

 kept growing in late summer and autumn (see p. 49). In such cold 

 localities no irrigation should be given after midsummer. 



It is interesting to note that the Wolf skill date (fig. 3, p. 31, and 

 Yearbook, 1900, PL LXII, fig. 2), which grows at Winters (latitude 

 38 32' north), about in the latitude of Washington, Lisbon, Athens, 

 and Peking, is much farther north than any bearing date palm in the 

 Old World, with the exception of one tree at Nice, France (latitude 

 43 45' north), which is probably not a true date palm but a hybrid 

 between the date palm and the Canary Island palm. There are other 

 date palms still farther north in the Sacramento valley which ripen 

 edible dates, as for instance at Colusa and Willows, at both of which 

 points date palms are growing which occasionally ripen a few fruits. a 



The Bee, Annual for 1902, p. 3: reported by Mr. J. M. Silvey, of Willows, and 

 W. S. Green, of Colusa. 



