126 Mas see. — A Revision of the 
present on the stem, the structure called the ring in systematic 
works being, so far as Coprinus is concerned, the free margin 
of the volva, or basal portion of the primary or universal veil, 
which, in some of the more highly organized species, breaks 
away from the lower fixed portion of the volva, and is carried 
for some distance up the stem during the increase in length 
of the latter. In some species, as Coprinus Hendersoni , Berk., 
this structure is situated about half-way up the stem, to which 
it is attached by its lower margin, and consequently looks 
much like a true ring formed from the remains of the 
secondary veil ; but it is in reality only the free margin of 
the volva, the lower portion of which closely embraces the 
stem, and is of a looser texture than that of the true stem 
above the margin of the volva. When the stem is thus 
surrounded for a considerable portion of its length by an 
adnate volva, it is said to be peronate. This appearance is 
produced by the increase in length of the stem being due 
mostly to basal growth, and in the volva growing at the same 
rate as the stem it closely surrounds ; when the volva does 
not grow at the same rate as the stem, then its free margin 
only is carried up by the elongating stem, as frequently seen 
in Coprinus comatus , Fries. This explanation is equally ap- 
plicable to all Agarics with a peronate stem. 
A clear idea of the broad lines of evolution — morphological 
and physiological — presented by the Agaricineae is necessary 
to enable the reader to judge of the view put forward 
respecting the genetic relationship of the genus Coprinus 
with the remainder of the series. 
Morphologically, the lowest and most primitive type of 
structure met with in the Agaricineae is illustrated by species 
included in such genera as Marasmius , Pleurotus , and Clau- 
dopus , where the pileus is sessile or stemless, and fixed by 
its back to the substratum, the gills being uppermost and 
consequently entirely unprotected from the earliest stage of 
development. In the second type the pileus is furnished 
with a more or less evident lateral stem, formed by the 
outgrowth of a point of the margin of the pileus, the gills 
