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 3 



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, not reviving 

 well when moistened : 



Ring or volva or both present — Genus 



Volva and ring both present Amanita. 



Volva present, ring absent Amanitopsis. 



Volva absent, ring present — 



Gills free from stem Lepiota. 



Gills attached to the stem Armillaria. 



Ring and volva both absent — ■ 



Stem excentric or lateral Pleurotus. 



Stem central — 



Gills decurrent — 



Edge blunt, foldlike, forked Cantharelltjs. 



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 



young Collybia. 



Cap thin, margin of cap at first straight, 



mostly bell-shaped Mycena. 



Cap fleshy, gills very rigid and brittle, stem 

 stout — 



Milk present Lactarius. 



Milk absent Russula. 



Gills various, often decurrent, adnate or only 

 adnexed, edge thin, thick at junction of cap, 



usually distant, waxy 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 



or ridges Marasmius. 



Stem central, excentric, lateral, or absent, substance of 

 cap continuous with that of stem — 



Edge of gills toothed or serrate Lentinus. 



Edge of gills not toothed or serrate Pantjs. 



Edge of gills split into two laminse and revolute Scthizophyixum. 



Plants corky or woody, gills radiating Lenzites. 



3 See the Glossary, p. 58, for definitions of technical terms. 



