$20 MISSOURI BOTANICAL GARDEN BULLETIN 
less foundation for the ancient joke that the way to tell a 
poisonous from a harmless species is to eat it. There thus 
were handed down by a sort of oral tradition certain facts 
about fungi as food which later became incorporated in 
various books on the subject. There has always been, how- 
ever, a great demand for a simple infallible rule whereby 
the novice could distinguish edible from poisonous forms, 
and the silver spoon test (in which silver blackens from 
dangerous mushrooms and remains bright if the fungus 
is harmless) and the supposed fact that all edible varieties 
have a top or cap easily peeled, were made much of.. Since 
the blackening of silver is due to the presence of protein- 
sulphur compounds which may occur in both the good 
and bad mushrooms, it has no value whatever, and other 
popular tests have been shown to be equally worthless. A 
moment’s thought makes it obvious that any such rules 
are as impossible of application to mushrooms as to any 
other plant or animal, for that matter. Mushrooms are not 
in a mysterious class by themselves. One must distinguish 
the various species, just as one tells the wild fruits apart, 
namely, by knowing them; and unless one becomes famil- 
iar with at least the more common wild mushrooms it is 
impossible to tell with certainty the good from the bad. 
There is no need to know the thousands of species, for no 
one, not even the expert, can recognize them all at sight. . 
However, to be able to accurately distinguish eight or ten 
forms is something, and to be familiar with fifty is to be- 
come almost an accomplished amateur. 
Undoubtedly the easiest way to fix in the mind the char- 
acters by which mushrooms may be distinguished is to 
study them by groups, a few at a time, with the actual 
specimens at hand and with an illustrated book for a guide, 
or with the assistance of some one who is familiar with the 
various forms. In the following paragraphs brief and un- 
technical descriptions are given of a few of the commoner 
varieties, and assisted by illustrations it is hoped that these 
may be sufficiently suggestive to encourage the reader in- 
terested in mushrooms to make use of wider opportunities 
and more detailed information, such as may be obtained 
from members of the Garden staff or is available in the 
mushroom books and manuals which are to be exhibited at 
the Garden. 
For the most part the mushrooms are members of one 
class of fungi, the Basidiomycetes, and this great group 
is subdivided into many families. There are five character- 
istic groups or families, namely, the Agaricaceae (gill 
fungi), the Polyporaceae (pore-bearing), the Hydnaceae 
