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5S ate = i cei oe Lei ek 
PES Ng RO eT is 
1902] CLADOCHYTRIUM ALISMATIS 57 
rhizoid-like process. The exact nature of these processes is not 
clearly shown, though very often they seem to bind the sporan- 
gial cell to the Sammelzellen. The sporangium while young 
contains numerous small oil globules scattered through the 
protoplasm, but these gradually unite into the one central oil 
drop. The sporangial walls also gradually thicken, become 
tinted, and the sporangium is finally matured (fig. 46). In the 
young sporangia there is some indication of a special place for 
the dehiscence of the cap. Young sporangia that were slightly 
crushed under a cover glass split off a cap on the side away 
from the Sammelzellen. This is evidently the side that in the 
mature sporangia is occasionally seen somewhat cupped. Mature 
sporangia, however, when crushed, do not always split open so 
regularly. 
The infection experiments were all made with the aquatic 
leaves of seedling plants. It seems very likely that the nature 
of the leaves determines the character of the sporangia formed, 
the exposed temporary sporangia being adapted to the peculiar 
aquatic leaves, and the internal resting sporangia to the aerial 
leaves. There were some indications that the temporary spo- 
rangia did not develop so abundantly on the later leaves, while 
in none of the aquatic leaves did the mature sporangia develop 
to such an extent as one might expect if these presented the 
most favorable conditions for their production. What different 
conditions determined, as was sometimes the case, the produc- 
tion of both stages on the same leaf was not discovered, but a 
possible explanation may be that the resting sporangia were 
developed from zoospores that after settling on the eg were 
exposed to the air. 
The time relations in the depeiendedt of the different stages 
of this fungus are shown approximately a the — obser- 
vations made in one case: 
March 21. Resting sporangia placed in water with young / Alisma leaf. 
March 23. Sporangia beginning to split off caps. — 
March 23-24. Active and quiet OOS, 
March a Some moors have See leaf to form young tempo- o : = a 
Tary § ; 
