CHARACTERS OF THE LEAVES OE THE DATE PALM. 19 



In the analysis of these characters (Table I) the Deglet Noor has 

 the highest percentage of spine area to total blade length and Hayany 

 the lowest. Menakher stands out from the group in having nearly 

 half of its pinnae of the introrse class, while Hayany has the lowest 

 percentage of any in that class. While Deglet Noor, Hayany, and 

 Thoory have a majority of their pinnae groups of the paired class, 

 Hayany leads in that respect in having but a fraction short of four- 

 fifths of its pinnae groups in the paired class. Menakher, on the other 

 hand, has a majority of its groups of the triple class. 



The descriptions of four date varieties which follow are given as 

 showing the application of this system of leaf study to the dates in 

 cultivation. Among the many varieties being tested in the gardens 

 of the Department of Agriculture these four take first rank in their 

 respective classes and present such a wide range in leaf characters 

 as to illustrate very clearly the principles involved. 



DESCRIPTION OF THE DEGLET NOOR VARIETY. 



The trees of the Deglet Noor variety have slender trunks and 

 make a rather rapid height growth, the leaves being 9 to 11 feet 

 long, erect spreading, forming a rather narrow vase-shaped top, 

 becoming broader with age. The leaf base is narrow, diminishing to 

 a firm, gradually tapering rib, which has a slight, graceful flexibility 

 at the apical portion. It is strongly rounded dorsally, well arched ven- 

 trally, with the lateral faces of more than average breadth (fig. 11). 



The spine area averages about 35 per cent of the blade length, the 

 spines firm, with stout bases, rather long, acuminate, acutely pointed, 

 crowded below, more scattered in the upper portion of the area, and 

 decidedly appressed. They pass to narrow spikelike pinnae, 12 to 18 

 inches in length, and the longest pinnae, 24 to 27 inches, are reached 

 at about the middle of the blade while but 1 inch to If inches broad. 

 The greatest breadth of the pinnae, If to 1§ inches, is usually at 

 about 6 to 7 feet from the base, where the pinnae are 20 to 24 inches 

 long. They diminish steadily to 10 or 15, or rarely 18 inches, in 

 length and seven-eighths of an inch to 1 inch in breadth at the apex 

 of the leaf. The pinnae throughout are acuminate in form and 

 acutely pointed, varying in thickness of the blade from 0.016 of an 

 inch (0.4064 mm.) to 0.022 of an inch (0.5588 mm.), from 0.017 of 

 an inch (0.1318 mm.) to 0.020 of an inch (0.5080 mm.) being the most 

 common, the texture being firm and rather harsh than soft. The 

 blades are closely folded, and toward the apex of the leaf the proxi- 

 mal fold is slightly wider than the distal and decurrent along the 

 rachis. The pulvini toward the base of the blade are heavy, some- 

 times strongly caudate, but the groups are seldom coalescent. 



The paired groups of pinna? are in the majority, often comprising 

 60 to 70 per cent of the whole number, while there are about 22 to 

 30 per cent of the triple groups, and a few are quadruple. 



