68 MOSSES IN THE VICINITY OF CLEVELAND. 



The teeth of the outer peristome always occur in a regular 

 geometrical ratio, being either four or some multiple of 

 that figure; hence they are found to consist of four, sixteen, 

 thirty- two or sixty-four. It is on this, with other peculiar- 

 ities of the teeth, the generic distinctions of the Mosses are 

 founded. 



The center of the capsule is occupied by a continuation 

 of the pedicle called an axis or columella^ and the space 

 between it and the sides of the capsule is filled with the 

 spores, which, when fully ripe, are discharged into the 

 atmosphere, floating with the vapor until they meet with a 

 proper nidus, or nest, for their development and growth. 



The oflice of the peristome seems to be the protection 

 of the spores from the injurious efii"ects of atmospheric 

 changes, as it is exceedingly sensitive to hygrometric 

 influences. When the air is dry and warm, with sunshine, 

 the teeth may be seen standing out at right angles with 

 the capsule, allowing the spores the full benefit of the 

 sun's benign influence, at the same time displaying the 

 beautiful and delicate texture of the inner peristome, but 

 during cloudy or damp weather, the teeth close tightly 

 over the mouth of the capsule so as to completely protect 

 the spores from external injury. 



Geographically the Mosses are diffused extensively, 

 much more abundant, however, in the humid localities of 

 the temperate and frigid zones. 



The figures at the head of this article are illustrative of 

 their botanical description. 



In these descriptions I shall begin with the genus 

 Rypnum^ the species of which are both numerous and 

 common. These plants are found in greatest abundance 

 in damp and wet localities, attached to rotten logs, moist 

 stones, roots of trees and occasionally on the ground in 

 shaded places. They are all perennials, and are both 

 monoecious and dioecious. 



