THE FERNS 



535 



We know that during the coal age many tree-ferns 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. 



T-rlSl?!''' 'Tti 



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



At the present day tree-ferns such as the 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 



