EVOLUTION OF PARASITIC FUNGI. 99 



because of the suggestions accompanying it which are often 

 turned to good account. It does not seem out of place, therefore, 

 at this time to point out what seem to me to be some of the ten- 

 dencies in the evolution of species among parasitic fungi, and at 

 the same time to call attention to some of the more practical 

 problems which may l)e profitably considered. 



Tendency toward a Wide Eaxge in Parasitism. — One of 

 the very striking tendencies which we see in the case of some 

 of the parasitic fungi is that of a wide range in parasitism, so that 

 the fungus is not confined to certain genera as hosts, nor even 

 to the families in which these genera are located, but the range of 

 their operations and injuries extends beyond these limits. In a 

 sense they are omnivorous, and such species sometimes receive 

 their specific name in recognition of the great versatility of their 

 tastes and depredations, and their easy adaptation to a great 

 variety of things in their gourmand-like search for dainty bits of 

 pabulum. 



The common fruit rot is a good example of the fungus appe- 

 tite which rarely goes begging for some satisfying morsel. It 

 appears to be king of rots in the case of certain of our stone 

 fruits, like the peach, plum, and cherry. But it also attacks the 

 pomaceous fruits, berries, etc., and finds the twigs of the peach, 

 cherry, and othei- fruits palatable. As with many other parasitic 

 fungi, its growth and the injuries which it causes are alike 

 hastened by the prevalence of wet or moist weather. It is also 

 much more likely to attack overripe fruit, and the fruit grower 

 who takes the precaution to pick his fruit for shipment while it is 

 still firm, or he who selects the hard-fleshed varieties, often check- 

 mates this enemy. The fact that it is more likely to attack the 

 overripe fruit or the soft-fleshed varieties, indicates that it is not 

 strictly an obligate parasite, and that, even when it is doing much 

 of its injury, it perhaps could not be said to be existing as a par- 

 asite, since the fruit is then in a very suitable condition to act as 

 an excellent culture medium. It does, however, act as a serious 

 parasite at times, and since it can adapt itself so readily to a 

 saprophj^tic or parasitic existence, the question might be raised 

 whether or not it is just now in the transitional stage, passing 

 from a saprophytic life to a parasitic one. If this were the 

 case we should expect that as time went on it would become more 

 and more dependent on the host in a living condition, and that 



