92 HOW TO KNOW THE FERNS 



appearance of three little balls, seeing that each 

 pinnae unfolds separately. The Limestone Poly- 

 pody occurs chiefly in the North of England. 



Polypodium alpestre. The Alpine Polypody. 

 This is a most remarkable species, in that it bears 

 a singular resemblance to the Lady Fern. By 

 some authorities it is positively regarded as a 

 Mountain form of the Lady Fern. The reason for 

 linking the species with the Polypodies is found 

 in the rounded son, which have no indusia. The 

 Alpine Polypody has a short tufted root-stock, 

 and from this arise the fronds, which may be a 

 foot or even more in height. The stipes is very 

 short when compared with the leafy portion, 

 and it is covered with brown scales. The 

 general outline of the fronds is broadly lanceo- 

 late, and they are twice divided. The pinnae 

 are arranged in alternation on either side of the 

 rachis, and these are divided into pinnules with 

 blunt points. The pinnules have toothed edges, 

 the son are chiefly situated near to the inside 

 border of the pinnules. Those who consider 

 that the Alpine Polypody is a form of the Lady 

 Fern call the species Pseudathyrium alpestre. 



The Alpine Polypody seems to be exclusively 

 confined, as far as the United Kingdom is con- 

 cerned, to the highlands of Scotland. It is 

 sometimes to be found at an altitude of four 

 thousand feet above sea-level. In spite of its 

 restricted locality the Alpine Polypody is an 

 easy subject for the garden, if it can be provided 

 with a well-drained situation. 



