33 FLOWERLESS PLANTS 



another species, a common enough kind on 

 walls, but very often overlooked on account of 

 its small size. The root-stock of this plant is 

 often tightly pressed between bricks or pieces 

 of rock, from which arise a number of small 

 fronds, sometimes only an inch or so in length. 

 As in the case of the Black Spleenwort, the 

 spore cases, when becoming ripe, swell up so 

 that the whole underside of the leaf is covered 

 with the brown masses. This very much adds 

 to the appearance of the handsome green leaves. 

 The Scaly Spleenwort {A. ceterach) is re- 

 markable for the manner in which the fronds 

 are protected on the underside with an abund- 

 ance of rust-coloured scales. There is little 

 doubt that these play a part in protecting the 

 foliage against undue loss of moisture, a danger 

 which is very real in the case of wall plants. 

 As well in dry weather the whole leaf rolls up, 

 so that most people might fancy that the fern 

 was dead. With the coming of moist weather 

 the normal habit of growth is resumed. The 

 spore cases which are clustered on the under- 

 side of the leaf have little in the way of a special 

 protecting scale, on account of the abundant 

 covering already mentioned. 



