THE FERNS 



535 



We know tliat during the coal age many trcc-tVrns like the 

 Pecopteris shown in Fig. 277 (page 299), apparently near of 

 kin to the adder-tongues, produced stout trunks bearing a 

 crown of ample leaves nearly twenty meters above the 

 ground. 



(^^^ 



Fig. 360.— Tree-Ferns and Herbaceous Ferns. (Baillon.) 



At the present day tree-ferns such as tlie one shown in 

 Fig. 360 abound in moist, warm regions, although the ferns 

 most common in northern lands are more like the smaller 

 ones shown in the same illustration. Thus it would appear 

 that a certain amount of degeneration has attended the 

 adaptation of ferns to the more stringent conditions of cold 



