CHARACTERS OF THE LEAVES OP THE DATE PALM. 



23 



the apex of the leaf (fig. 13). The spine area is unusually short, 

 about 18 to 25 per cent of the blade length, and the spines are 

 rather long, slender and acute; 

 where 4 considerably shaded 

 they are inclined to be weak 

 and soft. The spines merge 

 into narrow spike pinnae, fol- 

 lowed by ribbon pinnae 24 to 

 30 inches long and one-half to 

 five-eighths of an inch wide, 

 which are frequently pendu- 

 lous, but soon give place 

 through the middle of the 

 blade to those of normal form, 

 18 to 24 inches long and 1 inch 

 to 1^ inches up to 1 J or 2 

 inches wide with narrow at- 

 tenuate tips, gradually dimin- 

 ishing to about 10 or 12 inches 

 long at the apex. The pulvini 

 are but moderately developed 

 and creamy in color. 



The lower 10 or 15 pinnae on 

 either side have a solid neck, 

 which will be called the collum, 

 from one-half inch to 2 inches 

 in length, just above the pul- 

 vinus, from which the pinnae 

 expand into the folded blade of 

 normal form. These are most 

 strongly developed on the re- 

 trorse class of pinnae. This 

 character, while slightly devel- 

 oped in a few other Egyptian 

 varieties, is almost an identi- 

 fying character for this variety. 

 The pinnae blades are smooth 

 and rather soft, not rigidly acute 

 at the apex, but inclined to split 



Up. The axial divergence of fig. 13.— Cross sections of the rachis of a Hayany date 

 the pinnae is for the antrorse * ea *' s k° wm £ outlines at different distances from base 

 - _ , _ to apex. 



class, only about 20° to 35° 



near the base, becoming 45° or 50° toward the apex. The introrse 

 and retrorse classes diverge more strongly, in some leaves to 60° or 

 65°. In divergence from the plane of the blade the antrorse pinnae 



