116 SPORE DISSEMINATION 



pected of being carriers are slugs, snails, sow bugs, various rodents, 

 birds, and domestic animals. Slugs and snails feed upon a large 

 variety of fungi, especially powdery mildews, discomycetes, rusts, 

 mushrooms, polypores, and leathery fungi [Buller (1922), Wolf 

 and Wolf (1940)]. The spores either are voided or are dragged 

 along and scattered by the migrations of these animals in search 

 of food. Fleshy Hymenomvcetes appear to be especially attrac- 

 tive. Poisonous species are devoured with impunity. The pos- 

 session of a highly developed olfactory sense guides the animals 

 in the location of the fruit bodies of these species. Gravatt and 

 .Marshall (1917) made the observation that slugs (Agriolimax 

 agrestris), snails (Sabulina octona), and sow bugs (Armadillidium 

 -j nl gave) eat and distribute spores of Cronartium ribicola. Heald 

 and Studhalter (1914) found that birds, especially woodpeckers, 

 are of importance in the dissemination of Endothia parasitica. An 

 estimate of the numbers of spores of this fungus carried by two 

 downy woodpeckers {Dryobates piibescens medianus) was 757, 

 074 and 624,341 and by a brown creeper (Certhia jamiliaris ameri- 

 cana), 254,019. 



A number of fungi, notably species of Pilobolus, Sordaria, 

 Panaeolus, Anellaria, and Coprinus, normally occur on dung and 

 are regarded as coprophilous. Their spores are distributed by 

 such herbivorous animals as horses, cattle, sheep, goats, rabbits, 

 and geese. These animals swallow the spores and herbage to- 

 gether, and either the spores pass undamaged through the ali- 

 mentary tract or else their germination is favored by the digestive 

 enzymes which they encounter en route. After having been 

 eaten, the spores of these coprophilous species may remain for 

 hours within the alimentary tract before being voided in the feces. 

 Meanwhile the animal may transport them for miles. Soon after 

 discharge from the animal's body the spores will develop into new 

 plants, and their fruiting bodies will mature. Some dung-fungi 

 are especially adapted to such habitats. Buller (1934) has shown, 

 for example, that the sporangia of Pilobolus, on being shot away, 

 adhere to herbage 3 to 8 ft. distant from the dung heap. The 

 sporangia cling by virtue of the gelatinous material that arose by 

 dissolution when the sporangium separated from the swollen 

 subsporangium. Since these sporangia cannot be wet, they are 

 not affected by rains and in consequence may adhere intact to the 



