84 EVOLUTION Gr fire. 
chlorophyll, is never seen in any Fungi. With some ex- 
ceptions, the Fungi nourish themselves on organic matter, 
whereas plants combine inorganic matter, such as water, 
carbonic acid, ammonia, phosphates, etc., assimilating these 
principles in their growth. The-life-processes, the absence 
of amylum and ch 
orophyll, are such important facts in the 
economy of the Fungi that some naturalists deny that they 
are plants at all, and wish to place them in the intermediate 
kingdom referred to in the preceding chapter. The repro- 
duction of the Fungi, and the many transitional forms 
hardly distinguishable from Algae and Lichens, influence 
most botanists in regarding them as very aberrant, but still 
members of the vegetal kingdom. 
Most Fungi are parasitic in their mode of existence, living 
at the expense of the plant or animal on which they are 
found. 
The disease known as scald-head is due to the presence 
of a fungus, the Achorion; the thrush, a throat trouble, is 
caused by a fungus, the Oidium. Quite a flora has been 
described by Leidy and Robin as existing in the intestines 
of different animals, consisting principally of Fungi. T 
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1e 
Fungi are found, however, in the greatest profusion on 
decaying vegetal matter, stumps of trees, etc. being con- 
verted into powder by them. When halfeaten fruit is 
allowed to stand, soon it is seen to be covered with a 
whitish film, which, when examined under the microscope, 
— 
is found to be made up of the filaments of a Fungus. A 
Fungus, while essentially cellular, consists of two parts, the 
mycelium, or threads, and the colorless spores, or fruit: 
the threads are elongated cells, and resemble in position 
the stems of higher plants; the spores are seen at the end 
of the threads. (See Fig. 103, Grape Fungus) The 
spores are sometimes free (stylospores), or they are inclosed 
in what is called an ascus. (See figure of Stilbospora and 
Spheria, Fig. 104, 6, c) The arrangement of the spores 
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