FUNGI 81 



made in the way of favouring the presence of those fungi 

 that attack insects especially injurious to certain cultivated 

 plants and trees. This idea is as yet in its infancy, but it is 

 expected that good results will follow a more extended know- 

 ledge of the subject. 



Again, fungi must be considered as the scavengers of the 

 Vegetable Kingdom. All dead and dying vegetable matter 

 is seized upon by fungi, and soon reduced to a condition in 

 which it can be again utilised as food by plants ; whereas, 

 without the intervention of fungi, such material would remain 

 for ages before it decayed. Finally many fungi serve as food 

 for man, animals, more especially rodents, insects, etc. 



The most salient feature characterising fungi is their mode 

 of obtaining food, which differs so essentially from that of the 

 plants cultivated by the farmer and gardener. No fungus 

 obtains any portion of its food directly from the air or from 

 the soil, but depends entirely on the material composing the 

 bodies of animals or plants, more especially the latter. When 

 fungi obtain their food from living animals or plants, they are 

 called parasites, whereas when they derive their food from 

 dead plant substances, they are termed saprophytes. Many 

 fungi are strictly parasites or saprophytes, others are capable 

 of changing from one condition to the other, depending on 

 circumstances. 



Another peculiarity of many fungi is the totally different 

 appearance assumed during different periods of their life- 

 cycle. This is most marked in the group known as * rusts ' 

 and ' mildews ' of cereals and other plants. Not only does 

 the fungus differ in general appearance and structure during 

 different phases or stages of its development, but in many 

 cases the different stages in the development of the fungus 

 grow on different kinds of host-plants. This condition of 

 things is known as heteroerism, and is illustrated in rust or 

 mildew of wheat, where one stage of the fungus flourishes 

 on the leaves of the common barberry, while two other 

 stages of the same fungus grow on the leaves of the wheat 

 plant. 



The majority of fungus parasites, and other kinds also, in 

 addition to the higher form of fruit, have one or more 

 secondary or conidial conditions, which reproduce conidia or 

 summer-spores in rapid succession during the entire period 

 that the host-plan ti.e. the plant on which the fungus is 

 parasitic is in vigorous growth, and it is in almost every 



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