2 4 



HANDBOOK OF MOSSES. 



occurs, called the annulus (Lat, a ring). The function of 

 this ring is that of casting off the lid when the spores are 

 ripened, and thus aiding their dispersion; but in many 

 mosses, such as Tortula unguiculata, there is no annulus, 



FIG. ii. Encalypta streptocarpa. i, plant natural size. 2, mitriform calyptra. 

 3, fruit ; a, subulate lid ; 4, leaf magnified. 



and the lid is then cast off by the swelling of the contents 

 of the capsule. The operculum is not always present, and 

 here nature adopts other means to bring about the disper- 



FIG. 12. Urn or capsule of Pottia intermedia, i, naked mouth of urn. 2, beaked 

 or rostrate lid (operculum). 3, dimidiate calyptra. 



sion of the spores ; in the Andreseas, or split-mosses (fig. 13), 

 the capsule splits into four valves (fig. 13, 5), and in the 

 Phascums (fig. 14, i), or earth-mosses, the capsule bursts 



