26 THE DATE PALM. 



the temperature is low in the fruiting season the fruits will not 

 ripen properly. 



The development of the fruits appears to suffer no check from 

 cool nights, however, unless the temperature falls below a point 

 somewhere about 64 P 4F. (De Candolle, vide Swingle, page 63). 

 Certain varieties of dates ripen at lower temperatures than others, 

 and those varieties that ripen only in the hotter climates generally 

 appear to be superior in quality to those that ripen in cooler 

 climates. In most parts of the world, the fruits begin to form 

 about the end of April. If the climate is hot and the variety of 

 date is one that requires comparatively little heat to ripen it, 

 the fruits may be ripe as early as June, while if the climate is 

 cooler, or the variety one that requires more heat to ripen it, 

 the fruits may ripen as late as October or even November. In 

 some oases where harvesting labour is scarce, and the season 

 dry, or where there is some other reason for not collecting the 

 fruit as soon as ripe, it may be left on the trees for several weeks 

 after that. The world's date fruiting season is generally 

 reckoned as between 1st May and 31st October. 



Tables II, III, and IV on pages 27, 28, and 29 give as nearly 

 as the data to my hand will allow the monthly normal maximum 

 and minimum temperatures of date-growing localities in Tunis, 

 Egypt, Mesopotamia, and Persia. Table V, pages 30 and 31, gives 

 similar data for ten stations in the Punjab for comparison. 



