n so many inquiries for them and for literature
dealing with a larger number of species, it seemed desirable to publish
in book form a selection from the number of illustrations of these
plants which I have accumulated during the past six or seven years. The
selection has been made of those species representing the more important
genera, and also for the purpose of illustrating, as far as possible,
all the genera of agarics found in the United States. This has been
accomplished except in a few cases of the more unimportant ones. There
have been added, also, illustrative genera and species of all the other
orders of the higher fungi, in which are included many of the edible
forms.

The photographs have been made with great care after considerable
experience in determining the best means for reproducing individual,
specific, and generic characters, so important and difficult to preserve
in these plants, and so impossible in many cases to accurately portray
by former methods of illustration.

One is often asked the question: "How do you tell the mushrooms from the
toadstools?" This implies that mushrooms are edible and that toadstools
are poisonous, and this belief is very widespread in the public mind.
The fact is that many of the toadstools are edible, the common belief
that all of them are poisonous being due to unfamiliarity with the
plants or their characteristics.

Some apply the term mushroom to a single species, the one in
cultivation, and which grows also in fields (_Agaricus campestris_), and
call all others toadstools. It is becoming customary with some students
to apply the term mushroom to the entire group of higher fungi to which
the mushroom belongs (_Basidiomycetes_), and toadstool is regarded as a
synonymous term, since there is, strictly speaking, no distinction
between a mushroom and a toadstool. There are, then, edible and
poisonous mushrooms, or edible and poisonous toadstools, as one chooses
to employ the word.

A more pertinent question to ask is how to distinguish the edible from
the poisonous mushrooms. There is no single test or criterion, like the
"silver spoon" test, or the criterion of a scaly cap, or the presence of
a "poison cup" or "death cup," which will serve in all cases to
distinguish the edible from the poisonous. Two plants may possess
identical characters in this respect, i. e., each may have the "death
cup," and one is edible while the other is poisonous, as in _Amanita
caesarea