ii8 THE SCIENCE OF LIFE. 



The stems of Mosses usually terminate in filaments, 

 or foot-stalks, supporting an urn-shaped vessel closed by 

 a lid, (operculum!) which is covered by a cap, or hood, 

 (calyptra?) Under the operculum, the edge of the urn is 

 a beautiful toothed fringe, (the peristome!) and within the 



FIG. 47. --Structure of Mosses. A. Plant of Funaria hygrometrica, showing, f. the 

 leaves ; u. the urns supported upon the setae, or footstalks, j, closed by the operculum, 

 0, and covered by the calyptra, c. B. Urns of Encalyptra vulgaris^ one of them closed 

 and covered with the calyptra, the other open. u. u. The urns. o. o. The opercula. c. Ca- 

 lyptra. p. Peristome. s. s. Setae. C. Longitudinal section of very young urn of Splach- 

 num. a. Solid tissue forming the lower part of the capsule, c. Columella. /. Loculus, 

 or space around it for the development of the spores, e. Epidermic layer of cells, thick- 

 ened at the top to form the operculum, o. p. Two intermediate layers, from which the 

 peristome will be formed, s. Inner layer of cells forming the wall of the loculus. 



urn, or spore-capsule, (sporangium^) are double-coated 

 spores. (Fig. 47.) 



In developing into new plants, the outer coat of the 

 spore bursts and the inner wall protrudes. New cells 

 grow from the extremity, forming a filament, whose cells 

 at certain points multiply by subdivision, so as to form 

 rounded clusters, like the prothallus of Ferns, or the pro- 



