FUNGI 255 



mer on fleshy fungi, especially upon Boletus and its allies, the zygo- 

 sporic condition is not infrequent, because Sporodinia does not have + 

 and — strains. Rhizopus behaves like a dioecious plant, while Sporo- 

 dinia behaves like a monoecious one. The very damp atmosphere and 

 the nutrition necessary for the formation of zygospores may be pro- 

 vided 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 growing. 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 Jahr- 

 bucher fiir wissenschaftliche Botanik, 32:1-69, 1898. 



Phycomyces nitens. — This is a relative of Rhizopus, with a zygo- 

 sporic stage characterized by horny processes, which make it easily 

 recognizable. 



Zygorkynchus 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. 



No one has been able to germinate the zygotes of any of the above- 

 mentioned genera. 



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 12-24 hours throw the water away, rinse the flies in 

 clean water, and put them into tap water. The water must be changed 

 every day to keep bacteria from ruining the culture. 



Ants, or the larvae of ants, are often as good as flies. Small pieces of 

 boiled white of egg are excellent, especially if material is to be im- 

 bedded in paraffin. About 1 mm. cubes are large enough, and not 

 more than 20 cubes should be put into 500 c.c. of water. 



Sporangia may appear within 24 hours but may be a day later. Spo- 

 rangia may be produced in the greatest abundance by cultivating the 



