HOW FUNGI LIVE IN WINTER. 



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description are popularly considered as very transient, and as fre- 

 quently lasting for only a day. They start from a simple body called 

 a spore, produce a network of fine threads, yield a crop of spores in a 

 few hours, and the cycle of life is completed. We, however, find that 

 this round of multiplication is varied, and even these evanescent mil- 

 dews produce structures which serve the special purpose of carrying 

 the sjiecies over trying times of starvation, drought, or cold. The 

 common bread-mold {JSIucor stolonifer), for example, so abundant 

 upon stale viands in warm, moist weather, forms spore-bearing capsules 

 upon the tips of perpendicular threads, which, when ripe, burst, and 

 the multitudes of minute spores are scattered in all directions by every 

 passing breeze. As the bread begins to get dry, and fails to yield a 

 full supply of nourishment, the mold commences to develop a second 

 form of spore. These are produced by the union of the contents of 

 two filaments (conjugation), as shown in Fig. 1. The two Indian-club- 

 shaped branches are touching, end to end, at a and 5/ the union is 



</ 



Fig. 1.— Formation of Resting Spores op Beead-Mold. 



more advanced at c, while at d a central cell has formed, containing 

 the mingled contents of the two united cells. At e is seen the mature 

 spore, which has a thick, hard, black, and spiny covering, well adapted 

 to protect its highly vitalized contents from all injury. This spore, 

 though magnified ninety times in the engraving, is very much larger 

 than the exceedingly minute sacs of protoplasm formed in the capsules 

 above mentioned. The latter germinate at once, when favorably situ- 

 ated, but the larger black spore remains dormant for a considerable 

 time. Rapid reproduction is provided for in the multitudes of small 

 summer spores, while the preservation of the species is the end sought 

 in the formation of the thick-coated black spores. 



Passing from the minute molds that thrive upon bread, cake, etc., 

 we come next to those parasitic species of fungi growing in the tissues 

 of higher forms of plants. The grape-mildew {Peronos2)ora viticola) 



