54 MOSSES. 



CHAPTER VI. 



MOSSES, OR MTJS'CI (MUSCUS, MOSS) . 



I NEED scarcely refer to the figures in PL III. to 

 enable the reader to recognize the Mosses ; every one 

 knows them at once by their remarkably uniform 

 general appearance, their miniature-plantlike form, 

 their crowded little leaves, concealing the slender 

 wiry stems, their growth in patches, and their curious 

 urn-shaped fruits raised up on slender bristle-like 

 stalks. 



The leaves of the mosses are simple, i. e. not cut 

 into segments, and consist of one or two layers of 

 cells. The thinness of the leaves enables these cells to 

 be seen very distinctly, the closely united cell-walls 

 giving the leaves a netted or reticulated appearance 

 (fig. 48), and the grains of chlorophyll being gene- 

 rally few and readily distinguished. The veins of the 

 leaves, or the nerves as they are usually called, scarcely 

 deserve the name ; for neither they nor even the stems 

 contain fibro-vascular tissue, but consist simply of 

 elongate closely packed cells, and often the leaves 

 have no nerves. 



The fruit of the mosses consists of a capsule, some- 

 times called a sporangium (aTropd, seed, ^7709, vessel), 

 usually placed at the end of a slender stalk, called 

 the seta (seta, a bristle) ; but sometimes the stalk is 

 absent or extremely short, when the capsule is said 

 to be ses'sile (sessilis, sitting). The young capsule is 

 covered with a thin extinguisher-like cap or calyptra 

 (/ca\i>7rTpa, a cover), which is carried up as the cap- 

 sule and its stalk grow, so as to be either entirely 

 thrown off, or to remain covering a greater or less 

 portion of the capsule, when this attains maturity. 



