SOIL FUNGI 243 



Czapek's solution consisting of: 



Distilled water 1000 cc. MgS0 4 -7H 2 0.5 gram 



Cane sugar 30.0 grams KC1 0.5 gram 



NaN0 3 2.0 grams FeS0 4 0.01 gram 



K 2 HP0 4 1.0 gram (Sterilized at 15 pounds for 15 



minutes) 

 Since this medium contains cane sugar as a source of energy, and this is un- 

 favorable for the development of the majority of Mucorales, another medium 

 containing glucose as a source of energy should be employed for the isolation 

 and cultivation of these forms. This medium has the following composition: 



Cook's No. II medium: 37 



Distilled water 1000 cc. MgS0 4 -7H 2 0.25 gram 



Peptone 10.0 grams K 2 HP0 4 0.25 gram 



Glucose 20.0 grams Agar 15.0 grams 



Povah 38 employed the following medium for the isolation of Mucors: 



NHUNO3 1.0 gram Cane sugar. . 5.0 grams 



K 2 HP0 4 0.5 gram Agar 13.0 grams per liter 



MgS0 4 -7H 2 0.25 gram 



To prepare solid media, 10 or more per cent of gelatin or 1.5 to 2.0 per cent of 

 agar is added to the above solutions. In the case of acid media (at pH 4.0), 3 

 per cent agar is required. In addition to the media mentioned above, Povah 

 used another medium for stock cultures of Mucors: 



Peptone 1.0 gram Dry malt ex- 

 Glucose 20.0 grams tract 20.0 grams 



Agar 20.0 grams per liter 



For the cultivation of the wood-destroying Basidiomycete, Merulius lacrymans, 

 the following medium may be used: 39 



NH 4 N0 3 10 .0 grams .Lactic acid 2.0 grams 



K 2 HP0 4 5.0 grams Water 1000 grams 



MgSO-4-7H 2 1.0 gram 



50 cc. of this solution is added to 10 gm. of filter paper, the latter being used as 

 a source of energy. Species of Coprinus can be cultivated upon sterile horse 

 manure or manure decoction agar. Agaricus may be grown upon bread or bread 

 mixed with sawdust. 



Fungi will tolerate rather high concentrations of nutrients. Asp. 

 niger has its optimum at 20 to 30 per cent cane sugar, its maximum 



37 Cook, M. T. The relation of parasitic fungi to the contents of the cells of 

 the host plants. Del. Agr. Exp. Sta. Bui. 91, 1911. 



38 Povah, 1917 (p. 238). 



39 Tubeuf, C. V. Beitriige zur Kenntnis des Hausschwammes Merulius lacry- 

 mans. Centrbl. Bakt. II, 9: 127-135. 1902; Wehmer, C. Hausschwammgu- 

 tachten. Jahresb. Ver. angew. Bot., 8: 178-198. 1911. 



