214 AGRICULTURAL EXPERIMENT STATION, [Jan. 



the tissues of flowers or even of leaves and young twigs, 

 killing and browning all the tissues which they penetrate, 

 and rapidly spreading. Finally, these threads come to the 

 surface, and produce a new crop of spores. 



Besides the stone fruits, this fungus is known to attack 

 the apple, pear and others ; but its destructive effects seem 

 to be chiefly confined to the first named. My attention 

 was called, in July, 1890, to a loss of early peaches, amount- 

 ing to a very large percentage of the whole crop, in a small 

 orchard of the Massachusetts Agricultural College, just fol- 

 lowing several days of warm and moist weather. The 

 wholesale rotting then in progress was sufficient proof that 

 the germ threads of the fungus can penetrate the uninjured 

 skin of the peach, a power which has been doubted by 

 some writers, though lately proved in laboratory cultures by 

 Smith ; for it is not to be supposed that most of the fruits 

 on a tree were sufficiently injured ^o admit the entrance 

 of germ threads otherwise unable to penetrate them. The 

 mummied fruits usually remain hanging upon the branches, 

 or lie, without decaying, on the ground beneath, until the 

 following spring, when, as Smith has shown, the fungus 

 threads, which have lain dormant through the winter, 

 begin, under the influence of warmth and moisture, to 

 grow again, and soon the apparently dead and harmless 

 remains are covered with the ashy spore tufts, which will 

 infect the new season's crop. 



That the fungus does winter over in the dried flesh of 

 its victims was further shown last April, by placing mum- 

 mied plums, picked from the branches where they had 

 hung all winter, before the weather was sufficiently warm 

 to have caused any development, in a moist chamber in the 

 laboratory. In two days the plums were thickly covered 

 by the spore tufts of the fungus. A microscopic examina- 

 tion of the dried flesh from such plums just removed from 

 the tree showed the presence of numerous threads, com- 

 posed of large, thin-walled cells (Fig. 20, a), and of 

 single thick-walled cells of somewhat varying form, which 

 are probably to be regarded as the resting vegetative cells, 

 known as CJilaniydos^orcs or Gcinmce (Fig. 20, /5). It is 

 probably these cells especially which are able to withstand 



