CHAPTER V 



THE FUNGI 



ALL of the plants considered hitherto, except the 

 bacteria, have been characterized by the presence of 

 chlorophyll and the accompanying power of assimilat- 

 ing carbon dioxide as food. While the latter property 

 may be said to be characteristic of all typical plants, it 

 must be remembered that there are very many plants, 

 especially among the Thallophytes, where this power 

 is wanting, and which are quite destitute of any trace 

 of chlorophyll. It is usually supposed, although this 

 is not universally admitted, that these plants are the 

 descendants of green ancestors, and have lost their 

 chlorophyll through the adoption of parasitic or sapro- 

 phytic habits, i.e. feeding upon living or dead organic 

 bodies from which they derive the carbon compounds 

 necessary for their growth. All of these chlorophylless 

 plants below the mosses are known as Fungi, and con- 

 stitute a sub-kingdom which may be considered to have 

 been developed parallel with the Algse, or possibly 

 may have been derived from them. The Fungi are very 

 numerous, far exceeding the Algae in number of species. 

 Most of them are probably plants of comparatively 

 modern origin, as very many of them are dependent as 

 parasites upon various flowering plants, often being con- 

 fined to a single species as host, 1 and presumably have 



1 Host the animal or plant upon which a parasite lives. 

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