36 MORPHOLOGICAL DEVELOPMENT. 



Must we then conclude that as cells, or morphological 

 units, are integrated into a unit of a higher order, which we 

 call a thallus or frond ; so, by the integration of fronds, there 

 is evolved a structure such as the above-delineated species 

 possess? Whether this is the interpretation to be given of 

 these plants, we shall best see when considering whether it is 

 the interpretation to be given of plants which rank above 

 them. Thus far we have dealt only with the Cryptogamia. 

 We have now to deal with the Phanerogamia or Phgenogamia. 



