FEKNS OE GREAT BRITAIN. 29 



lower brandies, and the upper part of the frond. A. 

 distinct winding mid-vein may be seen in each pinnule 

 or lobe, whence issue lateral veins either simple or 

 shghtly branched, near the termination of which, towards 

 the margin, are placed the round clusters of fructifi- 

 cation, which in the autumn run into a crowded mass, 

 and form a marginal series. The underground stem of 

 this fern is dark-brown and creeping, and its fibiious 

 roots tough. Freshly gathered specimens exhibit a 

 degree of downiness on the frond. It is a rare fern, 

 growing among the loose stones of the limestone regions. 

 It does not thrive so well as several of the species in 

 gardens near towns, but sometimes in country gardens 

 it grows well, requiring lime to be mixed with the soil. 

 It Seldom grows very abundantly, though it is very plen- 

 tiful on the rocks of Buxton, about Matlock Baths, and 

 the Cheddar cliffs, for it seems never to grow wild except 

 in Hmestone districts. Some authors term it Lastrea 

 Bobertidna, Polypodiwm, Bobertidnum, or Gymnocdrpium 

 Bobertidnum. 



5. P. alpkstre (Alpine Polypody). — Fronds lanceolate, 

 twice pinnate ; pinnules linear-lanceolate, pinnatifid, with 

 blunt sharply-serrated lobes. This fern has but recently 

 been added to the hst of our British species. It has 

 long been known as a native of Switzerland, as well as 

 of several countries at the north and in the middle of 

 Europe. It was first discovered in Britain in 1841, by 

 Mr. Watson, on the mountains near Dalwhinnie, and at 

 Great Corrie of Ben Aulder, Inverness-shire. It was 

 not, however, until 1844, when this botanist again saw 

 this fern in Canlochen Glen in Forfarshire, that its claim 



