118 
large spherical head, the study of which is not easy. When placed in 
water it goes to pieces at once, leaving only a mass of colorless, cylin¬ 
drical cells 3-5 /y. long and 1-2/a. in diameter. The structure can 
be seen only when it can be observed in moist air under a cover glass. 
At the end of each branch of the mycelium is a globose, gelatinous 
mass, which swells strongly upon the addition of water and finally 
breaks in pieces. In it are imbedded a considerable number of the cells 
already mentioned, lying close together and parallel (Fig. 0). They have 
been cut off from the sporophore, and the gelatinous mass is composed 
of the envelopes of the individual gonidia. 
The ascospore has therefore produced a gonidia-forming mycelium, a 
Hyphomycetes , belonging to the form Acrostalagmus , as is shown by the 
peculiar structure of the fruiting head. This form seems to be different 
from that of A. cinnabarinus, Corda. When very finely developed it 
has the appearance of a reddish mat, but the sporophores are never 
branched as in A. cimiabariiius. The spores of the latter are smaller 
than those of the form uuder consideration, but the development of the 
spores and the relations of the gelatinous envelope differ in no way 
from those of A. cinnabarinus. When Acrostalagmus was cultivated in¬ 
dependently, its development was much more luxuriant; but pycnidia 
never made their appearance in these cultures; it seemed as if gonidia 
always reproduced the same gonidial form. It should also be mentioned 
that when the leaves were infected with ascospores Acrostalagmus 
nearly always appeared. 
The development of sporophores and formation of spores continues 
on the Fenestella mycelium for a long time. The great masses of spores 
which fall off* during the study of *the fungus often makes this very diffi¬ 
cult, and it is principally owing to them that the ascospores themselves 
are no longer visible. 
Afterwards new changes occur in the Fenestella mycelium. A dense 
mat is generally formed by the repeated branching of the hyphse and 
the formation of new ones from spores. This mat is called a stroma, 
although it deviates considerably from that formed in nature. At first 
the stroma of the slide cultures is not black or brown, but yellowish, 
which is probably caused by the rapid development incident to abun¬ 
dant moisture, for as a rule old cultures and those kept dryer take on a 
darker color. It can also be ascribed to the same cause, that the sepa¬ 
rate hyphse are more delicate than those observed in nature. The outer 
form of an artificially produced stroma is therefore different from the 
natural one, and it can attain considerable dimensions if the substratum 
is a favorable one. Besides it does not have tho conical shape de¬ 
scribed above, but forms a thin layer about 1 millimeter thick, upon, 
instead of within, which are the later formed pycnidia. We will return 
to this point farther on. 
About three or four weeks after the sowing of the ascospores, numer¬ 
ous brown bodies, about 1 millimeter in diameter, which proved to be 
