30 Minnesota Plant Diseases. 



rity very qiuckly elevated by a sponge-like stalk to a conspicu- 

 ous height. The spore-mass contains substances that eniit a 

 very strong odor as of carrion; hence the common name of 

 these plants. This odor is very attractive to many insects and 

 apparently the spore mass contains abundant food material 

 for it very soon disappears as a result of the numerous visits 

 of flies and other insects. In some forms of these carrion 

 fungi pure white veil-like or lace-like mantles — in appearance 



much like a large-meshed Wels- 

 bach mantle — are produced. 

 Certain tropical forms, more- 

 over, add a phosphorescence to 

 these mantles so that they at- 

 tract nocturnal insects, and such 



Fig. 13. — A birds-nest funpus.' To the ^ 11 • i. 



left are unopened fruiting bodies; formS OpCU USUally at Or JUSt bC- 



to the right a section of the same; - , , r-^ , • 1 1 • 1 i_ 



the eggs are chambers, carrying fOre dUSk. Certain moldS mhaO- 



spores, and the chamber stalks be- . , , 1 1 j • r 1 f • ±. 



come sticky when moist and prob- it the bodies of larvas ot msects, 



ably catch in the legs of insects and \--„„ „„_„ „;j.;„„11,, „„ tUa,^ A », 



are thus distributed. After Engier livmg parasitically ou them. An 

 and Pranti, and Sachs. -^^^^^^ ^^^^ infected may Carry 



the fungus to a considerable distance and after death numerous 

 spores will be formed which may infect new larvae. The silk- 

 worm is often preyed upon by these fungi. 



Distribution by other animals. Vertebrate animals are also 

 occasionally agents of spore distribution. Squirrels often feed 

 on certain mushrooms thereby carrying the spores off into 

 their holes. These fungi are the so-called wound parasites 

 which start life as saprophytes in the dead heart-wood of trees 

 and finally grow out into the sap-wood and kill the tree. In 

 the well-protected shelter of such squirrel holes a wound para- 

 site can get a good start. Rabbits and other burrowing ani- 

 mals often brush up against the fungus fruiting bodies of root- 

 inhabiting forms and carry the spores in their furry coats. 

 TrufHes are probably distributed by those animals which feed 

 on them. There is a very large class of fungi which inhabit 

 the dung of certain animals. Such fungi often grow from 

 spores which have passed through the alimentary canals of 

 these animals. The near relatives of the shaggy-mane mush- 

 room are good examples of these fungi. The common com- 

 mercial mushroom also regularlv inhabits dung and is there- 



