MESOZOIC EQUISETALES 85 



can form any conception of the variety of which this 

 type of organisation is capable, and of the high 

 differentiation to which it once attained. In fact, it 

 is no exaggeration to say that, as regards this important 

 Cryptogamic stock, the study of the fossil forms far 

 outweighs in scientific interest that of the few humble 

 species which have survived to our own day. 



