FERNS OF GREAT BRITAIN. 113 



membranous wing around the veins, that it has more the 

 appearance of a sea-weed than a fern. The frond is 

 between lanceolate and triangular in form, the divisions 

 being so much waved as to give it a crisped appearance. 

 It is three or four times pinnatifid, and the slender 

 segments of which it is composed are either entire or 

 two-cleft at the apex, and a strongly-marked and 

 stout vein runs up the centre. Indeed the veins are so 

 prominent and rigid, that they seem the most conspi- 

 cuous part of the fern, and the frond might very well 

 be said to consist of a number of firm veins, three or 

 four times branched, and edged by a thin green mem- 

 brane-like wing. Some of the terminations of the veins 

 are surrounded by the green part, which forms a little 

 cup in which lie the capsules of fructification. The 

 involucre, as this is usually called, most commonly pro- 

 jects beyond the margin of the frond, but it sometimes 

 lies within it, and the bristle is often four or five times 

 the length of the cup, though in many cases scarcely 

 exceeding it in length. The fronds are from three 

 inches to a foot long, and mostly droop over the sides 

 of the rocks. Though appearing in May, they are not 

 matured till about November, nor do they attain their 

 whole size or bear their fructification until the third 

 year of their growth. Now that it is discovered to thrive 

 so well in the closed cases, this plant is a favourite sub- 

 ject of the cultivator's care. It requires a pure and con- 

 stantly humid atmosphere, shade and warmth, and these 

 conditions can all be given by the glass case. It may 

 be grown also in an earthen pot standing in water and 

 covered with a bell-glass. A variety of this fern, of 



