THE DATE PALM. ] 447 



The oasis always consists of a natural depression in 

 the desert, of variable extent, with natural springs, or 

 with the underground water at no great depth and is 

 therefore easily raised to the surface by primitive 

 methods. The oasis is often enlarged by extending the 

 depression in the sand, and is kept up against the 

 encroachment of the wind by the untiring activity of 

 the inhabitants. The summer temperature is generally 

 over 3 j C and the sky is always clear, the desert region 

 being rainless or practically rainless, and there is little 

 danger of autumnal rains or of any excessive degree of 

 atmospheric moisture in September or October, which 

 would affect the crop of dates very seriously and prevents 

 it from ripening properly. According to an Arab proverb 

 the date palm must have its feet in the water and its 

 head in the sun. Under these circumstances it is no 

 wonder that generally speaking the date palm cannot 

 mature its fruit in these Islands, notwithstanding that the 

 flowers had been properly fertilized, and the fruit has a 

 well formed seed or stone quite capable of germination. 

 There are a few date-palms which mature their fruit 

 tolerably well, to be eatable either raw or cooked into 

 sweetmeats, but owing to climatic conditions all attempts 

 to grow the best Algerian and Tunis commercial varie- 

 ties have ended in failure, although it is not unlikely that 

 certain very early sorts would be more successful, such 

 as the Rhars of Northern Tunis, which should mature its 

 fruit before the commencement of the rainy season. 



The date palm is dioecious, the sexes being on 

 separate trees. One male tree is considered sufficient to 

 fertilize at least 200 female trees. Under natural condi- 

 tions the pollen is carried by the wind at considerable 

 distances, sometimes miles apart, provided of course that 

 at the flowering time the direction of the wind is from 

 the male tree to the female tree. Several species of 

 insects act also as pollen carriers for the date palm but 



