22 



Minnesota Plant Diseases. 



gregated together. They are found on threads more or less 

 loosely scattered about. In many higher fungi, however, the 

 spore cases or sacs are borne on special structures, called fruit- 

 ing bodies, though, of course, this term does not imply that 

 they are at all similar or equivalent to fruits, as the gardener or 

 horticulturist understands that term, when applied to parts of 



FIG. 9. Chief kinds of s >ores of fungi. 1. Sac with spores. 2. Basidia with basidio- 

 spores; a, b and c stages in s;>ore formation. 3. Spore case of mold containing numer- 

 ous spores. 4. Tuft of pinched-off spores of blue mold. 5. Swimming spores of an 

 algal fungus. 6. Spores of a black mold produced by a breeding act stalks of the 

 breeding cells are seen below the spore. 7. Spores of an insect mold. 1, 2 and 5 after 

 DeBary; 3 after Sachs; 4, 6 and 7 after Tirefeld. 



flowering plants. The best known of such fruiting bodies are 

 the common structures known as mushrooms and toadstools, 

 which in typical forms are composed of a stalk and an umbrella- 

 like cap, on the under surface of which are leaf-like plates, run- 

 ning from the edge to the top of the stalk. The spores are 



