not striate _Panaeolus_

In the Friesian classification which, with modifications, has prevailed
for many years among mycologists, the _genus Agaricus_ included in its
_subgenera_ the greater part of the species of the order _Agaricini_.
The subgenera, printed in the above table in italics, were included in
this genus. The genera are printed in capitals. In the Saccardian
system, all the _subgenera_ of _Agaricus_ having been elevated to
_generic_ rank, the term Agaricus is limited to a very small group which
includes the _subgenus Psalliota_ of Fries, the species being
characterized by fleshy caps, free gills, ringed stem, and dark brown or
purplish brown spores. As restricted, it naturally falls into the spore
series _Melanosporeae._

In the white-spored section, Leucospori, the recorded edible species
occur in the following genera: Marasmius, Cantharellus, Lactarius,
Russula, Hygrophorus, Collybia, Pleurotus, Clitocybe, Tricholoma,
Armillaria, Lepiota, and Amanita. The plants of Marasmius are usually
thin and dry, reviving with moisture. Cantharellus is characterized by
the obtuseness of the edges of the lamellae, Lactarius by the copious
milky or sticky fluid which exudes from the plants when cut or bruised.
Russula is closely allied to Lactarius, and the plants bear some
resemblance in external appearance to those of that genus, but they are
never milky, and the gills are usually rigid and brittle. In Hygrophorus
the plants are moist, not very large, often bright colored, and the
gills have a waxy appearance. The Collybias are usually caespitose, the
stems exteriorly cartilaginous, in some species swelling and splitting
open in the centre.

In Pleurotus the stem is lateral or absent. The plants are epiphytal,
usually springing from the decaying bark of trees and old stumps.

In Clitocybe the plants are characterized by a deeply depressed, often
narrow cap, with the gills acutely adnate, or running far down the stem,
which is elastic, with a fibrous outer coat covered with minute fibers.
Many of the species have a fragrant odor. The Tricholomas are stout and
fleshy, somewhat resembling the Russulas, but distinguished from them by
the sinuate character of the gills, which show a slight notched or
toothed depression just before reaching the stem (represented in Fig. 4,
Plate IV). Typical species of Armillaria show a well-defined ring and
scales upon the stem, the remains of the partial veil