CHAPTER XV 
THALLOPHYTES (Concluded) 
Fungi (Thallophytes Lacking Food-making Pigments) 
General Discussion. — The Fungi are a very large group of 
Thallophytes. There are thousands of different kinds of Fungi. 
Most people know some of the common forms, such as Toadstools, 
Mushrooms, and Puffballs, and those who live on the farm are 
probably acquainted with the Rusts and Smuts of our common 
cereals. Most of the plant diseases are caused by Fungi. Like 
the Slime Molds and Bacteria, they have no food-making 
pigment and consequently are either saprophytes or parasites. 
They attack both animals and plants. Plant Pathology, which 
is a study of plant diseases, devotes some time to the study of 
Slime Molds and Bacteria, but is concerned mainly with the 
Fungi. They attack vegetables, grains, fiber plants, fruits, fruit 
trees, and forest and shade trees. The destruction which they 
cause is enormous. Some of the parasitic forms, however, are 
harmless, and many of the saprophytic forms are beneficial. 
It is generally supposed that the Fungi are derived from the 
Algae, having lost their chlorophyll and independent living. 
Some of them have plant bodies, zodspores, sex organs, and sex 
cells similar to those of the Green Algae, while some have sex 
organs resembling those of the Red Algae, but have no resemblance 
in other features. Some have become so modified by their de- 
pendent habit of living that they have lost all of their alga-like 
features. They have made no advancement in evolution, for 
there is less differentiation of plant body in this group than 
in the Algae, and methods of reproduction show no improvement, 
but often are simpler than those of the Algae or have been lost 
entirely. Those botanists who study plants mainly from the 
standpoint of evolution devote very little time to the Fungi 
because they have contributed nothing to evolution. But from 
the economic standpoint, the Fungi are an exceedingly important 
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