118 THE NORTHERN MICROSCOPIST. 


which the spores are generated within the sporacular sac. The 
mouth of the capsule, with the exception of a few genera, is closed 
with a lid or operculum, surrounded by a ring or annulus which 
causes the lid to fall when the capsule is ripe, and discloses the 
beautiful series of teeth or Peristome, whose hygrometric action 
regulates the escape of the spores. The inner fringe of the 
Peristome when double is called the Endostome. 
The roots of Mosses for the most part are fibrous, springing 
from several parts of the stem, and in some cases even from the 
leaves. The leaves are destitute of any kind of stalk or petiole, 
being attached by their base and generally half enclosing the stem, 
hence semiamplexicaul. 
In the classification of Mosses authorities widely differ ; no two 
_ writers agreeing as to the exact arrangement of the orders and 
genera. Some prefer the artificial method which is based upon 
the nature of the Peristome—terming them Astomi, without lid ; 
Gymnostomi, without Peristome ; and Aploperistomi and Diplo- 
peristomi, with a single or double Peristome. 
The correct method is the natural one, based upon the agree- 
ment of the greatest number of parts. This was permanently 
adopted by Bruch and Schimper, upon whose work the last edition 
of the Bryologia Britannica was based. ‘The first two editions of 
this work were by Messrs. Hooker and Taylor; the last was revised 
and considerably extended by our greatest English authority, 
W. Wilson, of Warrington. 
Greater attention was paid to the fructification by Wilson, as the 
form of development affords permanent distinctions; and Hoff- 
meister states in his work on the higher Cryptogamia that this will 
prove to be the ultimate base of classification in the future; for 
although nothing is better known by botanists than the germination 
of the spores of Mosses, still only a small number have been 
thoroughlyinvestigated withregard totheir developmentindividually. 
All agree in artificially dividing Mosses into Acrocarpi, Cladocarpi, 
and Pleurocarpi; and the last edition of the London Catalogue 
has a fourth division termed Amphocarpi, containing three genera 
with Acrocarpus and Cladocarpus characters. 
The Acrocarpi are easily distinguished by their terminal fruit, as 
in Lryum hornum ; Pleurocarpi by their fruit being lateral to the 
creeping stem, as in the Hypnums; and Cladocarpi by fruit terminal 
on a lateral branch. 
The next distinction is the absence or presence of a deciduous 
lid. Those without lid being termed Schistocarpi, the capsules of 
which, as in the Andreeaceze and Sphagnacee, burst in a four valvular 
manner, and are thus linked to the Hepatic. The Stegocarpus 
Mosses, or those with a lid, are again divided into Mosses with no 
Peristome, with a single Peristome, and with a double Peristome. 

