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METHODS IN PLANT HISTOLOGY 
In the related genus, Sporodinia, which is rather common in 
summer on fleshy fungi, especially upon Boletus and its allies, the 
zygosporic condition is not infrequent, because Sporodinia does not 
have + and — strains. Rhizopus behaves like a dioecious plant, 
while Sporodinia behaves like a monoecious one. The very damp 
atmosphere and the nutrition necessary for the formation, of zygo¬ 
spores may be provided in the laboratory in the following way: Put 
a little water in a glass battery jar and place filter paper around the 
inside of the jar so that it will take up water and thus keep the sides 
of the jar moist. Place a small beaker or dish, without any water in 
it, in the bottom of the jar, and in the beaker place a small piece of 
bread dampened with the juice of prunes. Infect the bread with 
spores, or use a piece of bread upon which mycelium is already grow¬ 
ing. Sections of the root of Daucus carota may be used instead of the 
bread. Put a piece of wet filter paper on a pane of glass and cover 
the jar. Begin to examine after 24 hours. The zygospores may 
appear in 4 or 5 days. A very full account of the methods by which 
the various phases of the life-history of Sporodinia may be produced 
at will is given by Klebs in the Jahrbiicher fiir wissenschaftliche 
Botanik, 32:1—69, 1898. 
Zygorhynchus is another interesting relative of Rhizopus, readily 
distinguished by having suspensors of very unequal size. Dr. 
Florence A. McCormick sent us magnificent zygosporic material, 
raised on beef broth and fixed in 10 per cent formalin in water. 
Saprolegnia.—This is an aquatic mold, very common upon 
insects and algae. Cultures are easily and quickly made. Bring 
in a quart of water from any stagnant pond or ditch, and into the 
water throw a few flies. After 12 to 24 hours throw the water away, 
rinse the flies in clean water, and put then into tap water. The 
water must be changed every day to keep bacteria from ruining the 
culture. The larvae of ants or small pieces of boiled white of egg are 
sometimes better than flies. Sporangia may appear within 24 hours 
but may be a day later. Sporangia may be produced in the greatest 
abundance by cultivating the mycelium for several days and then 
transferring it to pure water or to distilled water. As long as the 
nutrient solution is sufficiently strong and fresh, only sterile mycelium 
will be produced. 
To secure oosporic material, mycelium which has been highly 
nourished for several days in a nutrient solution is brought into a 
