July, 1922] DODGE STUDIES IN THE GENUS GYMNOSPORANGIUM 
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sorus is shown at G. Hyphae pass around the stoma, showing in this 
section again at H, where both supporting epidermal cells are enlarged. 
The effect of the fungus near by is seen at /, hyphae appearing again in 
the section exploring new regions subcuticularly toward /. The epidermal 
cell at K is normal; no hyphae have advanced beyond this point in the leaf. 
The nature of the telium is even more evident in the cross section 
outlined in figure 5, where the epidermal layer is still unbroken from the 
stoma at the left to the limits of the sorus at the right. The cells of the 
epidermis are somewhat swollen, but 70 yu farther up some of them are 
nearly normal (fig. 6). Hyphae have crowded in between the longitudinal 
rows of epidermal cells at A, and two of these have been shoved aside, 
but they can be seen in the adjacent sections of the slide. 
Fig, 4. Part of a cross section of a leaf at the margin, showing a sorus above the 
epidermal layer, which is continuous. See also text. Fig. 5. Cross section of a portion 
of leaf through a sorus. The epidermal layer is unbroken, but the cells are swollen. The 
sorus originates between the cuticle and the epidermis. Fig. 6. Section of the same 
sorus 70^1 above. Mycelium has pushed in between the epidermal cells at A. Very 
little hypertrophy of the epidermal cells beneath the sorus here. 
It sometimes happens, especially in sections cut rather thick, that the 
portion of the cuticle raised above the sorus, and to which cling some of 
the disorganized remains of the cutinized walls of the epidermal cells, 
becomes turned over by pressure on the cover glass so that one is very 
likely to be misled into thinking that the sorus is really subepidermal 
or intra-epidermal because what appear to be portions of the epidermis 
