Algae, Fungi, and Lichens. 277 



outgrowths resembling leaves and performing the functions 

 of leaves ; so that both in the construction of the vegetative 

 parts and in the method of reproduction we find in them 

 close affinities to the higher plants. 



FUNGI. 



170. Character of Fungi. Turning now to the fungi, 

 we find plants which are characterized by their lack of 

 chlorophyll, and a consequent inability to utilize the energy 

 of the sunlight in the manufacture of their food. We find, 

 therefore, that they are either parasitic or saprophytic, 

 that is, they obtain their food from living or dead plants 

 or animals. They are closely allied to the Algae in their 

 structure and modes of reproduction, and may be their 

 degenerate descendants. 



171. Mucor, or Bread Mould. The common black bread 

 moulds, Mucor mucedo and Mucor stolonifer, are good repre- 

 sentatives of the saprophytic kinds of Fungi. The first- 

 named Mucor is composed throughout its whole vegetative 

 body of a much-branched unicellular filament which rami- 

 fies partly through the substratum and partly over its 

 surface, forming a somewhat felty coating. The wall of 

 the filament is thin and permits the transfusion of liquids. 

 The portion of the Fungus which is embedded in the sub- 

 stratum excretes a ferment that renders organic substances 

 soluble and adapted to absorption and assimilation. In 

 this way the Fungus is able to devour the starchy and 

 proteid substances of bread, vegetables, fruits, etc., and 

 even the cellulose composing cell walls. Such ferments 

 are extracted in large quantities from Fungi and sold on 

 the market in the form of digestive extracts or tablets. 



172. Reproduction of Mucor. Having accumulated a 

 sufficient amount of food materials, it proceeds to form its 



