CHAPTER XVII 
THE FUNGI 
The fungi or hyphomycetes constitute a great assemblage of 
thallophytes which are characterized by the total absence of 
chlorophyll. The members of this subdivision, “therefore, 
possess no independent power of manufacturing food materials 
such as starches, sugars, etc. from CO, and H2O. Conse- 
quently they are either parasites, depending for their nourishment 
upon other living plants or animals, called hosts; or saprophytes, 
depending upon decaying animal or vegetable matter in solution. 
Some forms are able to live either as saprophytes or parasites 
while others are restricted to either the parasitic or sapro- 
phytic habit. Some of the fungi like the bacteria and the yeasts 
are unicellular while others like the molds and mildews, etc. 
have bodies in the form of thread-like filaments called hyphe 
(sing. hypha) which are frequently branched. A mass of inter- 
tangled hyphz is called a mycelium. The hypha may be uni- 
cellular or multicellular. Fungal hyphe cither ramify through 
decaying matter or invade the tissues of living organisms and 
derive nourishment therefrom. In the cases of parasitic fungi 
like the rusts, etc., absorbing connections are present as hyphal 
outgrowths which penetrate into the cells of the host plant. 
These are called haustoria. In the higher forms the hyphz 
become consolidated into false tissues, and assume definite 
shapes according to the species. Of this character are the 
fruiting organs which constitute the above ground or exposed 
parts of Puff Balls, Cup Fungi, Bract F ungi, Mushrooms, 
etc. 
There are three classes of fungi, viz.: 
Class I Schizomycetes (bacteria) 
Class IIT Myxomycetes (slime moulds) 
Class ITI Eumycetes (true fungi) 
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