116 HISTORY OF BlllTISII FERKS. 



nearly opposite, and having more or less of obliquity, from 

 the larger development of the lower side. The pinnro are 

 pinnate, and the pinnules near their base often so deeply 

 divided as to be again almost pinnate ; the rest are pin- 

 natifid, or in the upper parts merely deeply-toothed, but 

 the margins, uhetlier deeply or shallowly-lobcd, are set 

 "vvith teeth which end in short spinous points. The vein- 

 ing is very similar to the more compound parts of the 

 allied species. Tlic fructification is produced in great 

 abundance, the sori beina; vanfred in two lines crosswise 

 the pinna? on the larger lobes, or lengthwise on the less 

 divided parts. The sori are covered by kidney-shaped 

 scales or indusia, which are fringed around the margin 

 with projecting glandular bodies. 



There is met with a variety or form of this Fern, which 

 has the fronds shorter, almost triangular in outline, and 

 often remarkably convex ; it has, moreover, usually a 

 dark green colour, often with a broAniish tinge. It is 

 found in more exposed places than the normal form, and 

 . is not uncommon. 



Another variety, sometimes called nana, seems chiefly 

 remarkable for its small size, seldom exceeding six or eight 

 inches in height, which peculiarity it maintains under cul- 



