Macrosporium parasiticum , Thilm . 2 1 
growth of long and branching chains of the Alternaria- spores, 
and no other forms of reproductive organs were to be found. 
In Van Tieghem cells, the mycelium behaved differently 
from that of the Sarcinula- spore. The hyphae were straighter, 
and slightly smaller in diameter, and they turned quickly to a 
brownish colour. Alternaria- spores were abundantly formed. 
No signs of the formation of a perithecium or pycnidium were 
observed during the whole cultures, except in one instance on 
the mycelium of a half-starved old culture, when a process 
which might be taken as an attempt at the formation of 
either pycnidium or perithecium appeared. 
I agree with Gibelli and Griffini and with Kohl in dis- 
carding Alternaria tenuis as a stage of Pleospora herbarum. 
In regard to the formation and development of the peri- 
thecia, my observations coincide in the main with those of 
Bauke described in his preliminary communication. Like him I 
have been unable to observe any sexual process connected with 
the formation of the perithecia, nor have I been successful in 
finding any trace of the Woronin’s hypha in a young peri- 
thecium before the formation of paraphyses and asci. The 
formation of the perithecium is entirely a vegetative process, 
which resembles essentially the formation of pycnidia. I do 
not consider the initial cells of the perithecia as degenerated 
female organs or ascogonia, but as entirely of vegetative origin. 
Both in the Alternaria- and Sarcinula- cultures I have 
observed the resting-hyphae, which were briefly described by 
Bauke. In the Sarcinula- cultures started in May these 
bodies were commonly formed on the mycelium floating free 
on the surface of the culture-fluid. Besides these common 
forms of the resting hyphae, I observed in the earlier part of 
the experiment varieties of abnormal hyphae in the Van 
Tieghem cell-cultures of the spores of Pleospora herbarum . 
As the growth and appearance of these bodies are very 
remarkable and interesting, I may give a brief description of 
them before closing this paper. 
In the Sarcinula- cultures, about five days after the sowing, 
a large number of club-shaped branches, filled with hyaline 
