FERN PLANTS 



253 



merit. They are frequently distinguished as the vascular 

 cryptogams to differentiate them from the other two 

 groups, cryptogams being a term sometimes used to desig- 

 nate the three orders of seedless plants. The distinction 



478. A water pteridophyte. Marsilia 479. Part of the fruiting 



(after GRAY). stem of a scouring rush, 



Equisctum limosuwi (after 



GRAY). 



between vascular and non-vascular plants is relatively as 

 important a one as that between vertebrates and inverte- 

 brates in the animal kingdom. 



Just what these three great groups are, and what relation 

 they bear to one another, will be better understood by the 

 study of a typical specimen of each. 



FERN PLANTS 



MATERIAL. Any kind of fern in the fruiting stage. The pretty 

 little ebony fern (Asplemum ebeneuni), and the Christmas fern 

 (Aspidittm acrosticheitUs) are common almost everywhere, the former 

 on shady hillsides near the foot of rocks and stumps, or in the shadow 

 of walls and fences ; the latter in rocky woods and along water courses 



