THE CLASSIFICATION OF PLANTS 



233 



Division II 



Phanerogams or . 



Seed-Plants 



Class I 

 Gymnosperms or seed-plants with naked ova- 

 ries, such as pines, spruces, cedars, and many 

 other evergreen trees. 



Subclass I 

 Class II Monocotyledonous 



Angiospeems or Plants 



seed-plants with Subclass II 



closed ovaries Dicotyledonous 



Plants. 



256. The Groups of Cryptogams. — The student is not 

 to suppose that the arrangement of cryptogams into the 

 four great groups given in the preceding table is the only 

 way in which they could be classed. It is simply one 

 way of dividing up the enormous number of spore-bearing 

 plants into sections, each designated by marked character- 

 istics of its own. But the amount of difEerence between 

 one group and another is not always necessarily the same. 

 The pteridophytes and the bryophytes resemble each 

 other much more closely than the latter do the thallo- 

 phytes, while the myxothallophytes are but little like other 

 plants and it is extremely probable that they are reaUy 

 animals. 



The classes given in the table do not embrace all known 

 cryptogams, but only those of which one or more repre- 

 sentatives are described or designated for study in this 

 book. Lichens in one sense hardly form a class, but it is 

 most convenient to assemble them under a head by them- 

 selves, on account of their extraordinary mode of life, a 

 partnership between algse and fungi. 



257. The Classes of Seed-Plants. — The gymnosperms 

 are much less highly developed than other seed-plants. 



