54 BRITISH FERNS. 



or less lobed or pinnatifid, the lobes being sharply toothed 

 in a varying manner. 



From the delicate herbaceous texture of the fronds the 

 venation is very distinct ; and is seen to consist, in each pin- 

 nule, of a wavy midvein, from which proceed alternate veins, 

 which again produce alternate venules, and on the anterior 



is borne an oblong sorus. In the larger and more divi 



pinnules the veining is more compound. The sori are them 



selves oblong, a little curved, the basal ones usually hippo- 

 cr^piform or horse-shoe shaped ; they are covered by indusia 

 of the same form as the sorus, and in the case of the curved, 

 or horse-shoe shaped sori, the indusium becomes apparently 

 almost circular with a lateral notch, in which state it resem- 

 bles a Lastrea. On one side the indusium is fixed longitudi- 

 nally to the side of the vein which forms the receptacle ; its 

 other margin, which is fringed, or split into a number of 

 hair-like segments, becomes free. This description applies 

 to the commoner forms of the Lady Fern, which, however, 

 are very variable in size, according to the situation and cir- 

 cumstances which influence their development, sometimes 

 scarcely exceeding a foot in height, and at other times reach- 

 ing the height of four or five feet, the latter being the result 

 of growth in a damp, shady situation, the former the conse- 

 quence of a more exposed and drier locality. 



The variety rhceticum, sometimes called convexum, differs 

 in its fronds, its pinnae, and its pinnules being narrower or 

 narrower-looking than in the common forms. The fronds, 

 which seldom exceed two feet in height, are erect, and their 

 form is narrow-lanceolate ; the pinnae are taper-pointed ; the 

 pinnules set quite clear of each other, very narrow, that is, 

 linear, with sharp points, the margins bluntly toothed, but 

 rolled under so that very little of the toothing is seen ; the 

 sori are very often confluent. It occurs in boggy places. 



The variety latifolium, also a very distinct and strong- 

 growing form, differs from the common sort, in the elongate 

 or oblong-lanceolate outline of its fronds, and in the broad, 

 leafy, crowded development of its ovate irregularly lobed 

 pinnules, which are deeply toothed at the margin, with the 

 curved sori lying near the sinuses of the lobes. It was found 

 in Westmoreland. 



The variety marinum has rather small fronds, usually 

 about a foot, or a foot and a half long, lanceolate, and re- 

 markable for the manner in which they taper from their 

 broad centre, equally towards the base and apex. These 



