THREE-BRANCHED POLYPODY. 85 



and one marvels how so tender and attenuated a stipes can 

 support so broad a frond. 



Its distribution in this country is northern and western. 

 From Derbyshire to Shetland it may be found in suitable places 

 fairly spread across the country except near to the East Coast. 

 But south of Derbyshire it will not be found east of Gloucester- 

 shire, although along the western half of the South it will be 

 found from Hants to Devon and Cornwall. The same thing 

 may be expressed otherwise by saying that the lines of N. 

 Latitude 53 and W. Longitude i mark off a south-eastern 

 district from which this fern is absent. In Ireland it is a local 

 fern, occurring in the counties of Antrim, Donegal, Down, 

 Londonderry, Wicklow, and Kerry. In the Highlands it 

 reaches an elevation of 3500 feet. It is found in those parts 

 of Europe, Asia, and America that lie within the North 

 Temperate Zone. 



We have already dealt with the names of this species, and 

 need only add to prevent misconception that, although not 

 restricted to high elevations, as the name we have preferred 

 might suggest, it is in the mountainous districts that it is chiefly 

 seen. 



Three-branched Polypody (Polypodium dryopteris). 



There is a double reason why we and our readers should not 

 consent to give further currency to the name Oak-fern com- 

 monly applied to this species by popular writers on Ferns. In 

 the first place, it is pre-occupied. All the old herbalists knew 

 the Common Polypody as the Oak-fern, and there was reason 

 for it, for although that species grew on other trees beside the 

 oak, the old patriotism, and reverence of the oak as the British 

 tree, led them to attribute greater virtue to a medicinal plant 

 that had grown on that tree and had, as they thought, imbibed 

 some of its character. The second objection we have already 



