COMPARISON OF FERNS. 293 



phyte. The prothallium bears also well-developed antheridia and arche- 

 gonia. The root, stem, and leaves of the sporophyte possess vascular 

 tissue. All the ferns and their allies agree in the possession of these char- 

 acters. The mosses and liverworts have well-developed antheridia and 

 archegonia, and the higher plants have vascular tissue. But no plant of 

 either of these groups possesses the combined characters which we find in 

 the ferns and their relatives. The latter are. therefore, the fern-like plants, 

 or pteridophyla. The living forms of the pteridophy ta are classified as fol- ,' 

 lows into families or orders. (See page 295.) 



