



MOSSES: THEIR STRUCTURE AND CLASSIFICATION. 11g 

In distinguishing genera, the Calyptra, the capsule, and areolation 
of the leaves are the most distinguishing features. 
The Calyptra, whether mitriform, mitre-shaped, or dimidiate, 
divided in the centre ; whether smooth or striate; and whether 
inflexed at the base or not inflexed. 
The shape of the capsule varies from globose and truncated to 
oblong-cylindrical, and is either upright or with every degree of 
inclination to that of drooping or pendulous ; the particular inclin- 
ation, however, is fairly constant in different genera, and there is 
a swelling at the base of many capsules termed an Apophysis. 
The areolation of the leaves may be either dense or open; round, 
angular, quadrate, or hexagonal; the basal cells, or those nearest 
the stem, differing considerably from those at the apex, and 
distinctly separates such closely allied genera as Dicranum and 
Dicranella, Bryum and Mnium. 
The form of the lid, with regard to its point, and the number of 
teeth in the Peristome also afford generic distinctions; the teeth 
being four, eight, sixteen, thirty-two, or sixty-four ; these numbers 
being a multiple of four, which is always constant. 
Specific characters are derived from the leaf, which varies in 
size, form, &c., its most marked characters being a midrib, which 
is either thickened and raised above the leaf, or transparent and 
buried in the leaf, this midrib terminating either below the apex, 
at the apex, or is carried beyond the leaf, excurrent, forming a 
hair-like point of very various lengths. With the exception of a 
few, as in the Mniums, the apices of all leaves terminate in a point, 
varying from obtuse to acute and needle-shaped. ‘The margins of 
the leaves are either entire, serrate, or cartilaginous, that is, with a 
thickened border, and may be either incurved or decurved ; while 
the surface is smooth or papillose, studded with round or pointed 
prominences. 
The insertion of the leaves is also characteristic, and is either 
two, three, four, five, or eight ranked, according to the number 
requisite to circumscribe the stem. 
Mosses are Monoicous, Dioicous, or Synoicous. Dioicous 
species having the male and female organs on separate plants. In 
Monoicous species the organs are on separate branches of the 
same plant; while Synoicous species have both Antheridia and 
Archegonia in the same inflorescence. 
Many Mosses are both Monoicous and Dioicous, and a few are 
Monoicous, Dioicous, and Synoicous. 
Although they have many features in common, the foliaceous 
Hepaticze are widely separated from the true Mosses by their leaves, 
which have no midrib, are more delicately membranous, and are 
rounded at the apex or deeply cleft. 
A great number of the Hepaticz have also stipular appendages. 
