POLYPODIES. 



49 



siderable elevation, and is often found in company with 

 the Lady Eern. 



A desirable variety is cultivated under the name of 

 jiexile, the fronds of which fall back nearly horizontally, 

 and are almost destitute of foot-stalks. The average length 

 is from 9 inches to a foot, and it is altogether much more 

 elegant than the original form. 



It is not many years since the Alpine Polypody was 

 first recognized as a distinct species, and even now some 

 persons express doubts whether it occupies its proper 

 position amongst the Polypodies. 



No special cultivation seems to be necessary for this 

 fern. It is too large for any ordinary-sized Wardian 

 case, but can be grown in pots in the greenhouse, or in 

 a sheltered open-air fernery. 



OAK PEEN.^ 



The Oak Pern has a slender creeping root-stock, from 

 • which proceed the graceful triangular fronds, borne on 

 slender, dark-coloured stipes, twice the length of the 

 leafy portion of the frond. The outline of the fronds is 

 triangular, divided into three nearly equal branches, the 

 outline of which is also triangular. Each branch has its 

 lower portion divided into distinct leaflets, which are again 

 divided nearly to the central vein in a feathery manner. 

 The upper portion of the branches is cleft into lobes, gradu- 

 ally becoming more divided towards the base. Hence the 

 branches are said to be pinnatifid above, and pinnate 

 below, with the pinned again pinnatifid. The sori are 

 scattered about the under surface of the frond. 



This fern is not uncommon in Wales, in the north of 

 England, and in Scotland, in mountainous situations. 

 AVhen growing in the chinks of the stone walls along the 

 roadside in Wales, it flourishes freely, but to remove it 

 is a task of no small difficulty. Indeed, it is almost im- 

 possible to get out the roots entire, except by removing 

 the stone above or below it. 



* Pohjpodium dryopteris, Linn. 



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