194 Methods in Plant Histology 



In the related genus, Sporodinia, which is rather common in 

 summer upon fleshy fungi, especially upon Boletus and its allies, the 

 zygosporic condition is not infrequent. The very damp atmosphere 

 and the nutrition necessary for the formation of zygospores 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 Jahrbucher fur wissen- 

 schaftliche Botanik 32:1-69, 1898. 



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 them into tap water. Spo- 

 rangia will probably appear within 24 hours. 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 better than 

 flies, if sections are to be cut. 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 0.1 per cent solution of leucin, or into a . 05 

 to 0.1 per cent solution of haemoglobin. Begin to examine after 

 24 hours. 



