12 



BULLETIN 223, U. S. DEPARTMENT OF AGRICULTUKE. 



antrorse pinnse. They may lie nearly in the plane of the blade, but 

 they usually form angles back of that plane which must be measured 

 dors ally. 



Toward the base of the blade the groups may irregularly coincide 

 on opposite sides of the rachis, giving the pinnae a tufted appearance 



■1 



i 



i 



* 



*^ 





Fig, 6.— Micrometer, reading to 0.001 of an inch, 

 for determrning the comparative thickness of 

 pinnae of date leaves of difTerent varieties. ^^^- 7.— Combination 2-foot rule and protractor with 



vernier for determining the angles at which date- 



and leaving naked spaces of SeV- leaf pinn^. diverge from the rachis. 



eral inches between them. In other examples the groups may be 

 coalescent through the caudate pulvini, or they may be so crowded 

 that the pinnae overlap like the slats in a window bUnd. 



Figu 



middle, but 



groups 



± CD ± 



and below by the 



( 



J" ^ 



pulvini of the antrorse pinnse 



