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



Plate V. 





&^ 



lb 



Freehand Vertical Sections of Pecan Leaves. Frotscher 

 Variety. 



SemidiagraiamaUc camera-Iucida drawings of diseased and Iiealtliy leaves, showing tissue 

 changes due to rosette. Collected on August 25, 1919, at Thomasvillc, Ga. All of same mag- 

 nification. The small side diagrams show the relative size and shape of the leaves and the 

 locations of the sections. A. — Section through the center of a thin, yellow area, showing 

 close pacldng of the colls and lack of dilTerenlialion. B. — Section at (he margin of the 

 yellow spot in the green portion of a leallet , showing the close packing of I he cells and 

 the partial decrease in the long axis and increase in the short axis ol' imlisade cells. ('.—Sec- 

 tion through a healthy leaflet, showing iialisade and spongy tissue well de\elii|ied and Ihc 

 looser arrangement of the spongy cells, Ihe narrower openings being inlercellnlar s|)aees. 

 D. — Section of a mottled, linear leallet, showing the close packing of the cells and only ])artial 

 diiferentiation of the palisade cells. Drawings by the writer. 



