Bui. 1038, U. S. Dept. of Agriculture. 



PLATE X. 



Vein Islets of Unsectioned and Unstained Pecan Leaves. 



A, and C to E are from photomicrographs of leaves preserved in alcohoL B is from a pliotomiero- 

 graph of a dry herbarium specimen. All at the same magnification. X about 60. The white 

 spots are calcium-oxalate crystal aggregates. A to D. — Yellow spots of rosetted leaflets in the 

 secondary stage, showing the distortion in shape and the variation in size of the vein islets. E. — 

 Similar view of vein islets in a normal leaflet, showing approximately uniform size and regular 

 arrangement. Photomicrographs by the writer. 



