(Sometimes there is a faint tinge of pink or lilac when the spores are in bulk, but the color is not seen under the microscope.)

=Plants= soft, fleshy or nearly so, usually soon decaying; dried plants do not revive well when moistened. 1

=Plants= tough, either fleshy or gelatinous, membranaceous, corky or woody, persistent, reviving when moistened. 13

=1=--=Gills= acute on the edge. 2

=Edge= of the gills obtuse, or gills fold-like, or vein-like, but prominent. 12

=2=--=Trama= of the pileus of interwoven threads, not vesiculose. 3

=Trama= of the pileus vesiculose, plants rigid but quite fragile. 11

=3=--=Gills= thin, not much broadened toward the pileus. 4

=Gills= broadened toward the pileus, of waxy consistency. =Hygrophorus.= 110

=4=--=Stipe= central or sub-central.

(Some species of Pleurotus are sub-central, but the gills are usually not decurrent.) 5

=Stipe= on one side of the pileus, or none, rarely with the stipe sub-central.

(Some species of c.l.i.tocybe are sub-central.) =Pleurotus.= 102

=5=--=Stipe= fleshy, pileus easily separating from the stipe, gills usually free. 6

=Stipe= fleshy or fibrous and elastic, pileus confluent with the stipe and of the same texture. 7

=Stipe= cartilaginous, pileus confluent with the stipe, but of a different texture. 9

=6=--=Volva= and annulus present on the stipe. =Amanita.= 52

=Volva= present, annulus wanting. =Amanitopsis.= 74

=Volva= wanting, annulus present. =Lepiota.= 77

=7=--=Annulus= and volva wanting. 8

=Annulus= usually present (sometimes vague), volva wanting, gills attached to the stipe. =Armillaria.= 83

=8=--=Gills= sinuate. =Tricholoma.= 87

=Gills= decurrent, not sinuate. =c.l.i.tocybe.= 89

=9=--=Gills= decurrent, pileus umbilicate. =Omphalia.= 100

=Gills= not decurrent. 10

=10=--=Margin= of pileus at first involute, pileus flat or nearly so, somewhat fleshy (some plants rather tough and tending toward the consistency of Marasmius). =Collybia.= 92

=Margin= of the pileus at first straight, pileus slightly bell-shaped, thin. =Mycena.= 93

=Gills= usually free, pileus deeply plicate so that the gills are split where they are attached to the pileus, pileus membranaceous, very tender but not diffluent. =Hiatula.=

=11=--=Plants= where bruised exuding a milky or colored juice. =Lactarius.= 114

=Plants= not exuding a juice where bruised. =Russula.= 125

=12=--=Gills= decurrent, dichotomous, edge blunt. =Cantharellus.= 128

=Gills= not decurrent, plants parasitic on other mushrooms. =Nyctalis.=

=13=--=Edge= of gills not split into two laminae. 14

=Edge= of gills split into two laminae and revolute. =Schizophyllum.= 136

=14=--=Plants= leathery, either fleshy, membraneous, or gelatinous. 15

=Plants= corky or woody (placed by some in Polyporaceae). =Lenzites.=

=15=--=Stipe= separate from the pileus (hymenoph.o.r.e), easily separating. 16

=Stipe= continuous with hymenoph.o.r.e. 17

=16=--=Plants= tough and fleshy, membranaceous or leathery. =Marasmius.= 130

=Plants= gelatinous and leathery. =Heliomyces.=

=17=--=Edge= of the gills acute. 18

=Edge= of the gills obtuse. 19

=18=--=Edge= of gills usually serrate. =Lentinus.= 134

=Edge= of gills entire. =Pa.n.u.s.= 134

=19=--=Gills= dichotomous. =Xerotus.=

=Gills= fold-like, irregular. =Trogia.= 137

There are only a few rare species of Hiatula, Nyctalis, Heliomyces and Xerotus in the United States. None are here described.

THE OCHRE-SPORED AGARICS.

(The spores are yellowish brown or rusty brown.)

=Gills= not separating readily from 1

=Gills= sometimes separating readily from the pileus, forked or anastomosing at the base, or connected with vein-like reticulations. =Paxillus.= 165