1 8 WAYSIDE AND WOODLAND FERNS. 



up the vertical faces of exposed rocks far from any protecting 

 trees or shrubs. Such colonies, of course, are frequently 

 bathed in the mists that visitors find too much of a hindrance 

 to their examination of natural objects at high elevations, and 

 when the air is sufficiently dry and clear to permit so small an 

 object as a Filmy-fern to be seen, it appears dry and lifeless, 

 like many of the mosses that company with it. It is more 

 likely to be seen by the moss-collector than by the inexperienced 

 fern-hunter, for it looks more like one of the brown moss 

 colonies that are so plentiful in the same habitats. 



Doubts have been expressed whether the two Filmy-ferns 

 are really distinct, or merely sub-species of one. There is a 

 good deal to be said for the second view ; at the same time it 

 should be pointed out that the differences in " habit " and the 

 character of the indusium render them so distinct that a 

 beginner in fern-lore would have no difficulty in separating 

 them. In unilaterale there is a strong tendency for the pinnae 

 on opposite sides of the midrib to bring their under surfaces 

 together, which, of course, greatly contributes to its withered 

 appearance. Then, too, whilst the toothed urns of tunbridgense 

 remain almost in the same plane as the back of the frond, 

 those of the present species stand out conspicuously at right 

 angles from the midrib, and have a more swollen form. The 

 frond is also of a stiffer substance and darker hue ; more 

 oblong in shape, and the pinnae are divided mostly on the side 

 nearest to the tip of the frond. The urn-like body is here more 

 obvious, not only because of its superior size, but largely as a 

 result of the way in which it stands out on its distinct footstalk 

 from the curved surface of the frond. The two valves of which 

 it is composed are, moreover, entirely without the teeth which 

 interrupt the upper margins of tunbridgense. These capsules 

 are sufficiently large and so placed that they may be seen 

 clearly in some parts of the photograph, though the fronds, 

 from their dark green and admixture of brown, make very 



