82 THE BRITISH FERNS. 
We have seldom seen cultivated plants of this species thriving 
with the vigour they possess in their native hills, except when 
grown fully exposed to the air in sheltered shady situations and in 
a pure atmosphere. When confined within doors, especially in 
smoky localities, they often produce but puny and flaccid fronds. 
It roots, however, freely in a sandy compost of loam and peat, and 
with a free admission of air may be grown with tolerable success in 
frames or cool fern houses where it is necessary to use these means 
of sheltering plants of this nature from atmospheric impurities. In 
all cases, however, where a pure atmosphere is enjoyed, it will be 
found to grow better on the open rockery, than in pots under glass ; 
and when it is found requisite to adopt frame or house culture, the 
plants, though shaded, should be provided with as airy and light a 
situation as can be found. In situations where it can be grown out- 
doors the species is perfectly hardy, of erect habit, and not inelegant, 
though by no means comparable in beauty with some states of the 
Lady Fern, which it most resembles. The variety flerile forms a 
beautiful pot plant for a cool house or frame, its delicate spreading 
and gracefully curving fronds giving it a character of distinctness as 
well as elegance. The plants require good drainage, as they like a 
tolerable supply of water; and though they must have moderate 
shade they are not benefited by being placed in a confined situation. 
They may be increased by separating the lateral crowns of the 
caudex, as well as like most other Ferns, from the spores. 
. This Polypody is a very variable plant, but we have as yet no 
experience whether the variations are generally such as would be 
perpetuated under other conditions than those in which they natu- 
rally occur. The forms we have received from the natural habitats 
have a remarkable correspondence, as regards their general character 
and division, with those of Athyrium Filic-femina. The most 
striking of them are enumerated as sub-varieties below, with the 
object of recording, as we have done in other cases, the most 
marked modifications of development to which the species is subject. 
1. flexile (M.). This is a narrow lax form, with deflexed pinne ; 
and bears perhaps in its irregular toothing, and singular habits of 

