384 THALLOPHYTES 
are divided into a number of orders. The most familiar orders 
are those represented by the Toadstools and Mushrooms (Hy- 
menomycetes), Puffballs Ea SenOm ES Smuts (Ustilaginales), 
and Rusts (Uredinales). 
Toadstools and Mushrooms (Hymenomycetes). — This is the 
most familiar order to most people, because it includes so many 
forms like the Toadstools and Mushrooms, which have conspicu- 
ous sporophores. In addition to the Toadstools and Mushrooms, 
the order contains some other rather familiar kinds of Fungi. 
The Fungi of this order are chicfly 
saprophytes, living on decaying wood, 
leaf mold, rich humus, and manure. 
Often the organic matter upon which 
they are living is not visible and they 
seem to be growing right out of the 
soil. As the name of the order sug- 
gests, they have a hymenium, and 
the hymenium, which consists of 
basidia commonly intermingled with 
sterile hyphae, is borne exposed. 
Usually the hymenium is on the 
under side of the sporophore where it 
is protected from rain. 
Those of the order having umbrella- 
shaped sporophores are popularly 
: called Toadstools and when edible 
ire Sar qivineas they are popularly called Mushrooms. 
Toadstool, Amanita bulbosa. The term Mushroom, however, is 
xe often applied to Morels and all kinds 
of Fungi that are edible. There are 
several hundred species of edible Fungi in the United States 
and more than one hundred of them are of the Toadstool type. 
Some of the Toadstools are deadly poisonous, as the one shown 
in Figure 337, and many that are not poisonous are tough, 
fibrous, or ill-tasting and hence not edible. Between edible and 
non-edible Fungi there are no botanical distinctions or guides. 
By experience people have learned that some species are edible 
and some non-edible, and many sad accidents have occurred as a 
result of not being able to distinguish the poisonous from the 
edible ones. 
