Minnesota Plant Life. 81 



% 



or red. Here may be included a curious fungus which is par- 

 asitic on toadstools. When a toadstool is affected by this par- 

 asite the gills are all destroyed and the area they occupied pre- 

 sents a pimply red surface. The pimples are small, about the 

 size of a pin-head, and in each of them is developed a mass of 

 spore-sacs. Such a plant illustrates the tendency of what were 

 independent fruit-bodies in the truffles, the blights and the blue 

 moulds, to aggregate themselves into layers. Such layers are 

 in higher forms of black fungi variously disposed over branch- 

 ing or swollen bases, so that a large compound fruit-body is 

 developed. 



Ergots. A good example of an interesting black fungus 

 with a compound fruit-body is the well-known ergot of rye. 

 Ergots occur, however, upon other plants than the rye, and, 

 for instance, a very interesting kind is found in the fruiting 

 panicles of the wild rice. The life-history of an ergot is about 

 as follows : The plant-body develops within the tissues of the 

 grass and when the grass is ready to set its fruits, the ergot 

 plant, somewhat after the manner of smuts, produces in some 

 of the .kernels, a dense network of filaments, occupying the 

 place of the grain. The ergot does not here, however, form its 

 spores as the smuts do, but gives rise rather to a tuberous 

 propagative body, consisting of a softer white interior, with a 

 black shell and exactly comparable to the underground tubers 

 formed, as mentioned above, by one kind of cup-fungus. Such 

 ergot tubers take about the same shape as the rye kernel, finally 

 falling out from between the chaffy scales of the rye and lying 

 dormant over winter. In the spring, buds arise under the skin 

 of the tuber and grow out into little slender threads and at the 

 end of each a more or less spherical swelling appears. The sur- 

 face of the swelling is occupied by a layer of ergot fruit-bodies, 

 in each of which a group of slender sacs, with long jointed 

 spores, is developed. It should be added that other sorts of 

 spores, ovoid in form, are produced upon wrinkles at the surface 

 of the propagative tuber, so that as in so many other fungi, 

 there are here two kinds of spore-cells. Either variety of spore 

 falling upon the proper host plant will infect it and initiate the 

 development of a new ergot plant-body. 



7 



