1921] MILES—-LEAF SPOTS OF ELM 169 
connected with a single ascogonial coil. In G. ulmea also, as 
previously stated, one finds (fig. 16) certain hyphae which pass out 
through the upper leaf surface in a quite similar manner, although 
not through a stoma in this case, since stomata are absent on the 
upper surface of an elm leaf. In this case, however, there is no 
possibility of their being mistaken for anything else than vegeta- 
tive hyphae. It is quite likely that those of G. erythrostroma are 
of a similar nature. BLACKMAN and WELLsFoRD described in 
Polystigma rubrum trichogynes similar to those of Brooks, but on 
account of an inability to trace a direct connection with the asco- 
gonium, concluded that they were merely vegetative. In earlier 
papers Fiscu (17) and FRANK (18) had both described and fig- 
ured such connections and had designated the hyphae as true 
trichogynes. Although Brooks continued to call the projecting 
hyphae in G. erythrostroma trichogynes, and although he found 
both ascogonia and spermatia present, he concluded that the 
trichogynes were no longer functional, and that fertilization did not 
actually occur through their agency. He suggested as a present 
function for them that they might serve as respiratory channels 
for the fungal hyphae within the leaf, where the assimilatory pro- 
cesses must necessarily have been considerably curtailed by the 
dying of the tissue. Such a function would also give reason for 
the existence of similar hyphae in G. ulmea, especially since the 
presence of the black stroma would tend even more to impair the 
respiratory processes in the host tissue beneath it. 
The ascogonium in the young perithecium of G. u/mea soon 
begins to break up into segments, each cell becoming separated 
from the others. Brown (7) noticed a similar segmentation of 
the ascogonium of Xylaria tentaculata, as did also Miss Dawson 
in Poronia. They found that those segments gave rise to the 
ascogenous hyphae in the fungi with which they were working, 
but I have been unable to ascertain this fact with certainty in 
G. ulmea with the material at hand. It is almost a certainty, 
however, that this is the case here also, since the segments of the 
ascogonial coil can be distinguished near the base of the perithe- 
cium until after the asci have commenced their development. 
