HISTORY OP BRITISH FERNS. 



fronds of this kind of Pern produce fructification, which, 

 however, is usually confined to the upper half of the fronds, 

 and has generally become mature by the end of September. 



The most important variety is the Welsh Polypody, called 

 Polypodium camdricum by Linnseus. In' this the lobes of 

 the frond are broader, and, instead of being simple, are 

 deeply and irregularly lobed a second time, the segments 

 being rather sharply toothed. This form, which is cer- 

 tainly only a variety of the common Polypody, is almost 

 always found without fructification. Under slight shelter, 

 where its fronds are persistent, it is one of the most beautiful 

 of what are called hardy Perns. 



Other varieties which have been proposed are bifidum, 

 in which the lobes are more or less regularly two-cleft at 

 the apex; serratum, in which they are deeply saw-edged; 

 and acutum, in which they are drawn out to a long narrow 

 point. The forms, however, are not constant, and are hence 

 of but small importance. 



The species and its varieties grow freely under culti- 

 vation, either planted in pots, or on rock-work in a shady 

 situation. 



