BBTOPHTTA. 



213 



cases there have been observed bundles of thin-walled cells 

 extending from the leaves to the bundle in the stem. It 

 cannot be doubted, then|pthft the Mosses possess rudimen- 

 tary fibro-vascular bundles. As in liverworts, the tissues 

 of mosses develop from a single apical cell. Breathing- 

 pores resembling those of the higher plants occur on the 

 spore-fruits; they are not found upon the leaves or stems. 



393. Mosses, for the most part, grow upon moist earth 

 or rocks, or upon the sides of trees ; comparatively few are 

 aquatic. They range in size from 

 less than a millimetre to many centi- 

 metres in length, the most common 

 height being from two to four centi- 

 metres. They are all chlorophyll- 

 bearing plants, and are generally of 

 a bright- green color; occasionally, 

 however, they are whitish or brown- 

 ish. 



394. The reproduction of mosses 

 is mainly sexual, but often brood- 

 masses are found resembling those 

 of liverworts. The sexual organs 

 develop either upon the end of the 

 stem, within flower-like rosettes of 

 leaves, or in the axils of the leaves. 



The antherids are club-shaped or 

 globose trichomes (Fig. 1^5), whose 

 interior cells (sperm-cells) produce fig. las.— ^, an antherid 



^ ^ of a Moss ruptured, show- 



antherozoids. The sperm-cells, when mgthemassofsperm-ceUs, 



■■^ 'a, magnmed 350 times j 



mature, escape from the antherid ^ViS|™howizSTther- 

 through a rent in its wall. Bach ''^°''^' '^'^^''^ ^* "' *^'''=- 

 sperm-cell contains one spirally coiled antherozoid, which. 



