Bui. 1038, U. S. Dept. of Agriculture. 
PLATE X. 
f 
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 photomicro- 
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. 
