LABORATORY STUDIES 197 
Mount a few filaments (as directed in 7 above) and examine 
filaments, sporangia, and spores. 
(k) Moisten a piece of bread and then sow here and there on 
its surface a few spores of Black Mold; cover with a tumbler or 
bell glass. In a few hours a new crop of Black Mold will begin 
developing. The nutritive mycelium may be studied by 
teasing out small bits of the newly infected bread. 
(2) Place several clean glass slides in contact with a culture of 
black mold, as described in (k). By removing these at different 
times the various stages of growth of the mold may be easily 
studied. 
(m) Collect a number of large fleshy fungi (Boletus, Lactaria, 
Agaricus, etc.) and place under bell jars for a couple of days. 
Usually a cream-colored mold (Sporodinia grandis) will begin 
to develop upon some of these. Transfer it to pieces of bread 
as in (k) and study in a similar way. After a few days the 
zygospore formation will be observed, as this species is homo- 
thallic. 
(n) In the latter part of summer and in the autumn examine 
the dead flies which adhere to windowpanes, door-casings, and 
especially to wires and strings hanging from the ceiling. The 
whitish powder around the fly will indicate the presence of the 
Fly-fungus (Entomophthora muscae). Mount some of this 
white powder in water and examine under a high power. Tear 
out small bits of the distended abdomen of the fly, and examine 
for internal portions of the parasite. 
(0) In the autumn look for dead grasshoppers attached to the 
tops of weeds and grasses. Examine their interior tissues for 
thick-walled resting spores of Entomophthora grylli. 
(p) In damp weather in the summer look for Botrydium on 
the hard, smooth ground of unused paths. It often appears 
on compact soil in greenhouses in the winter. 
(q) Specimens of Valonia, Bryopsis, Caulerpa and Acetabu- 
laria may be obtained of dealers in laboratory material for 
study and examination. 
(r) Search the sandy margins of ponds, lakes, and slow streams 
for Stoneworts (Charales). They are generally found in water 
from a few centimeters to one or two meters in depth. Pre- 
serve such specimens temporarily in water which is frequently 
changed, but for future use preserve in alcohol. Study as 
follows. 
