PREFACE. 



The arrangement adopted in the following paper is taken from 

 the " Epicrisis Systematis Mycologici," of Elias Fries, published 

 at UiDsal in 1838, and from the "Anleitung zum Studium der 

 Mycologie," of A. C. J. Corda, published in 1842. 



The descriptions of species have been chiefly taken from notes 

 made at the time when the plant was collected. The terms em- 

 ployed in the English Flora have however been used when con- 

 sidered to apply better than any others to the specimens in hand. 



The principal parts of an Agaric are, first the pileus, the hori- 

 zontal portion of the plant, which is generally elevated on a stem. 

 The form of its upper surface varies from sub -cylindrical or conical 

 to umbilicate or infundibuliform. When its convexity becomes more 

 acute towards the centre it is said to be umhonate. The under 

 surface of the pileus is furnished with vertical plates or gills 

 radiating from the stem. "When the giUs are attached to the stem 

 by their whole breadth they are said to be adnate, if in contact 

 only wnth the stem, they are adnexed ; if not in contact, they are 

 free ; if continued down the stem they are decurrent. Sometimes 

 they are sinuated, or emarginate, or rounded off behind, that is 

 next the stem. 



Wlien the plant is young the margin of the pileus is attached to 

 the stem by a membrane or web, veil, which is ruptured as the 

 pileus expands and may be left on the stem forming a collar or ring. 

 In many species the veil is absent or so delicate as to be imperceptible. 

 The pileus and stem when young arc sometimes enveloped in a 

 H 57 



