Bui. 1038, U. S. Dept. of Agriculture 
Plate XI 
Fresh Living Cells of Pecan Leaves. 
Camera-lucida drawings of freehand vertical sections, mounted in water. All at the same mag- 
nification (X about 1,200) and oriented the same as in the leaf. A.— Health y palisade cell, 
showing well-defined nucleus and plump livid-green chloroplasts. B. — A disorganization stage 
of a palisade cell in a leaf affected with rosette; chloroplasts disintegrated and nuclear outline 
vague. C— Healthy cell of the spongy parenchyma. D.— Slightly diseased cell of the spongy 
parenchyma in which the chloroplasts have lost a part of their green color. E. — Spongy paren- 
chyma cell at the margin of a yellow area. The protoplasmic structures on the side toward the 
spot (right) are disorganized and the nucleus is fragmenting. Chloroplasts next to the green 
periphery of the spot (.left) are still green and unfragmented, though a part of them are smaller 
than normal. F and G. — Spongy ceUs at further stages in disorganization. H. — Spongy cell 
showing entire disorganization of contents. I.— Tannin degeneration products gathering into 
flocules at a later stage of the disease in a spongy cell. J. — Spongy cell at the red-brown stage 
with more or less homogeneous reddish brown contents plasmolized. K. — Spongy cell at the 
margin of a yellow area (right) showing chloroplasts red-brown, but unfragmented on the side 
toward the spot. This form of injury is rather uncommon. Drawings by the writer. 
