SOME TYPES OF FLOWERLESS PLANTS. 233 
sitic or saprophytic plants which were formerly all grouped 
as fungi, but which now are often divided among many 
classes.1_ Chlorophyll is absent from fungi, and they are 
destitute of starch, but produce a kind of cellulose which 
appears to differ chemically from that of other plants. 
Unable to build up their tissues from carbonic acid gas, 
water, and other mineral matters, they are to be classed, with 
animals, as consumers rather than as producers, acting on the 
whole to diminish rather than to increase the total amount of 
organic material on the earth. 
289. Occurrence and Mode of Life of Fungi.— Among the 
most important cryptogamous plants are those which, like the 
bacillus of consumption, of diphtheria, of typhoid fever, or 
of cholera, produce disease in man or in the lower animals. 
The sub-class which includes these plants is known by the 
name bacteria. Some of the most notable characteristics of 
this group are their extreme minuteness and their extraordi- 
nary power of multiplication. Many bacteria are on the 
whole highly useful to man, as is the case with those which 
produce decay in the tissues of dead plants or animals, since 
these substances would, if it were not for the destructive 
action of the bacteria of putrefaction and fermentation, 
remain indefinitely after death to cumber the earth and lock 
up proteid and other food needed by new organisms. 
The “rust” of wheat and the “smut” of corn are well- 
known fungi parasitic on other plants, and the number of 
such species of fungi already known is not less than 42,000. 
Fig. 201 shows clearly how a parasitic fungus grows from a 
spore which has found lodgment in the tissues of a leaf and 
pushes out through the stomata. | 
The largest fungi are those of the group to which the 
edible mushrooms, the toadstools, puffballs, and so on, belong. 
1See Strasburger, Noll, Schenck, and Schimper’s Lehrbuch, p. 259; also Warm- 
ing’s Systematic Botany (translated by Potter), p. 1. 
