50 ROMANCE OF LOW LIFE AMONGST PLANTS. 



LIVERWORTS. 



THIS is a small order of cryptogamous plants, 

 related to the mosses, and sometimes vaguely, 

 but inaccurately, included with them. In appearance, 

 the typical forms at least, resemble mosses, in having 

 organs analogous to a stem and leaves ; but differing 

 in the more delicate and filmy substance of those 

 leaflets. More characteristic still is the difference in 

 fruit, which in mosses is mostly contained in a capsule, 

 opening by a lid, with a fringed mouth, and in liver- 

 worts with a splitting receptacle (Fig. 9) but without a 

 lid. These distinctions, however, need not be insisted 

 upon here, because short general descriptions are 

 never satisfactory, and this is a technical question, 

 outside our present limits. It may be added, how- 

 ever, that the spores within the receptacle in liver- 

 worts, are often mixed with spiral thread-like organs, 

 called elaters, which are absent in mosses. 



If we go back to Lindley's " Vegetable Kingdom " 

 of 1847, we ascertain that the estimated total of 

 species of the Hepaticce at that period was seven 

 hundred. The present number can only be guessed, 

 but, on the basis of certain knowledge, it may be 

 assumed at not less than two thousand, although we 

 believe it to be more. 



