SOME COMMON MUSHROOMS AND HOW TO KNOW THEM 5 
appear as the mushroom expands, or it may persist as a definite or 
cobwebby ring around the stem or as a fragmentary or cobwebby 
veil on the margin of the cap. 
In the early stages of some genera the entire plant is inclosed in 
an envelope known as the volva. The manner in which this envelope 
breaks is of great importance in identifying species and should be 
carefully noted at the time the collection is made. In some cases it 
remains at the base of the plant as a complete or fragmentary cup 
or sheath, or as ridges on the lower part of the stem, or as scales on 
the top of the cap. 
KEY TO AGARICACEAE$ 
The following key will be found a convenient means of distin- 
guishing between the different genera of Agaricaceae. It will be 
observed that the first character to be considered is the color of the 
spores. This may be easily determined by using the method ex- 
plained on page 4. Further points of difference are to be found in 
the presence or absence of the volva or of the veil, in the shape of 
the pileus, attachment of the gills, shape and marking of the stem, 
manner of growth, habitat, or some other distinguishing feature. 
WHITE-SPORED AGARICS 
Plants soft or more or less fleshy, soon decaying, nct reviving 
well when moistened : 
Ring or volva or both present— Genus 
Volvayandoring both: presen tke ne ees es AMANITA. 
WMolyaw present. ring absent. == a2 tae eee ae AMANITOPSIS. 
Volva absent, ring present— 
CETL US) eee YeN a £3 GCOS Oa NES) oS 00 a a ee ore te LEPIOTA. 
Gillssattachedetosthe: stemmae as ie eee ARMILLARIA. 
Ring and volva both absent— 
Stembexcentric or lateral a 2.22 See ee se _ PLEUROTUS. 
Stem central— 
Gills decurrent— 
Edge blunt, foldlike, forked_______________ CANTHARELLUS. 
Edge thin, stem fibrous outside____________ CLITOCYBE. 
Edge thin, stem cartilaginous outside______ OMPHALIA. 
Gills sinuate, general structure fleshy__________ TRICHOLOMA. 
Gills adnate or adnexed— 
Cap rather fleshy, margin incurved when 
VOUT Omran at ha een Re ee ce COLLYBIA. 
Cap thin, margin of cap at first straight, 
MOSthybelleshaped oem ene a a MYCENA. 
Cap fleshy, gills very rigid and brittle, stem 
stout— 
IY GUUS op ES (2) 01 ee ees A OR Ne ee LACTARIUS. 
Mink ea SE mn (ase eet area Be oe Ss RUSSULA. 
Gills various, often decurrent, adnate or only 
adnexed, edge thin, thick at junction of cap, 
USUAL EGISEAIN G4 FWiaxyea es er HYGROPHORUS. 
Plants coriaceous, tough, fleshy, or membranaceous, reviving 
when moistened : 
Stem generally central, substance of cap noncontinuous 
with that of stem, gills thin, often connected by veins 
OIRO Og Sar eee rere more, eee eee eee ee MARASMIUS. 
Stem central, excentric, lateral, or absent, substance of 
cap continuous with that of stem— . 
Mdgesot sills toothed or serrate. 2-2 LENTINUS. 
Edge of gills not toothed or serrate_________________ PANUS. 4 
Edge of gills split into two laminze and revolute____ SCHIZOPHYLLoM, 
EIDE Corky, OL woody, gills; radiating= = 5 ea at LENZITES. 
3 See the Glossary, p. 58, for definitions of technical terms. 
