STRUCTURE AND FUNCTIONS 27 



Insects are great carriers of spores, which are carried 

 either on or within their bodies. In fact, many fungi 

 which are the cause of serious diseases would be of little 

 consequence if it were not for insects. Insects also aid 

 many fungi by feeding on plants and producing wounds 

 by which the fungi gain entrance. 



Spores are carried by larger animals in the same 

 manner as by insects, namely, on or within their bodies. 

 Small animals carry them into their burrows, and large 

 animals carry them from place to place. The spores of 

 many fungi will readily pass through the alimentary 

 canal of an animal uninjured, and are frequently 

 distributed in the manure. 



Spores are carried on plants, and in the soil and 

 packing materials around the plants, which are shipped 

 from place to place and country to country, in stock 

 cars, on the wheels of wagons, on the feet of the labourers, 

 on pruning tools, and in many other ways which receive 

 very little attention. 



Some fungi are provided with an explosive apparatus, 

 by which the spores are thrown to considerable dis- 

 tances, and are then more readily caught by the wind 

 and carried. Some of the black moulds develop a 

 peculiar explosive structure just beneath the sporangium, 

 which matures just as the spores are ripe, and explodes 

 with sufficient force to throw the entire sporangium into 

 the air. The cups of the cup fungi are lined with little 

 tubes which stand upright. When the spores are ripe 

 these tubes open at the end, and the spores are forced 

 into the air in such abundance as to form very noticeable 

 little clouds. 



Resistance and Germination. Spores show very 

 great differences in vitality. Some of them die very 

 quickly when exposed to unfavourable conditions, while 

 others may live for a number of years. As a rule, the 

 spores which live in an excess of moisture cannot 

 withstand much drying. Those spores which will tolerate 

 a long period of dry condition will usually withstand 

 greater variations in temperature when dry than when 



