Minnesota Plant Life. 



49 



times affects them has gained a foothold, they might as well 

 save themselves the trouble, for all the pollen grains will have 

 been destroyed and in their place will be the spores of the smut. 



Peat-moss smut. Still another kind of smut develops its 

 spores in the capsules of the peat-moss, and under such condi- 

 tions when the capsule opens to eject its spores there are no 

 moss-spores present, but only the smaller black reproductive cells 

 of the smut. Until recently this condition of things caused bot- 

 anists to labor under a misapprehension concerning the life- 

 history of the peat-moss and in most of the books peat-mosses 

 are described as producing two kinds of spores, some large and 

 others small. The supposed small spores of the peat-moss are, 

 however, not peat-moss spores at all, but are developed on a par- 

 asitic plant which has the interesting habit of forming them in 

 exactly the same little round capsule which the peat-moss had 

 been to the pains of developing for its own spores. 



The life of a smut. A large number of plants in Minne- 

 sota are affected by smuts and sometimes two or more va- 

 rieties will be attacked by the same kind. More often, how- 

 ever, the smuts which are found on different kinds of higher 

 plants are themselves specifically distinct. The life of a smut 

 is interesting because it is typical of the manner in which many 

 parasitic fungi develop. There may be selected for description 

 the stinking smut of wheat. Inside the affected kernels clusters 

 of spores are formed which upon the breaking of the kernels, 

 during the threshing of the wheat or while it is being shovelled 

 about in bins or while it is standing in its head, are liberated and 

 fall upon the ends of other uninfected kernels. There they are 

 caught in the little hairs which are present at the germinal end, 

 and when the wheat kernel is sown and germinated the smut 

 spores germinate also and their delicate threads grow in the tis- 

 sues of the wheat plant keeping pace with the host as it extends 

 higher and higher into the air. When the wheat flowers are 

 formed and the rudiments of the fruits begin to appear some 

 of the smut filaments grow into the young kernels and, as these 

 develop, the smut filaments begin dividing themselves into 

 spore-cells, exerting a disintegrating effect upon the interior of 

 the kernel, so that finally one thus infected becomes filled with 

 thousands of spores of the smut. The process may then be re- 

 .s 



