THE EEIAN OR DEVONIAN FORESTS. 



75 



Another very remarkable fern, which some botanists have 

 supposed may belong to a higher group than the ferns, is 

 Megalopteris (Fig. 26). 



Somejof the Erian ferns attained to the dimensions of 

 tree-ferns. Large stems of these, which must hare floated 

 out far from land, have been found by Newberry in the 

 marine limestone of Ohio {Gaulopieris antiqua and G. 

 peregrina, Newberry),* and Prof. Hall has found in the 



Fia. 25. — An Erian tree-fern. Cmtlopteris LoekwooM, Dawson, 

 reduced. (From a specimen from Gilboa, New.York.) 



Upper Devonian of Gilboa, New York, the remains of a 

 forest of tree-ferns standing in situ with their great 

 masses of aerial roots attached to the soil in which they 

 grew {Oaulopteris Lochwoodi, Dn.).f 



These aerial roots introduce us to a new contrivance 

 for strengthening the stems of plants by sending out into 

 the soil multitudes of cord-like cylindrical roots from 



* "Journal of the Geological Society," IS'Zl. 



\ im. 



