PERNS OF GREAT BRITAIN. 75 



they mature, they form one dark-brown thick mass, 

 almost covering the whole of the imder-surface of the 

 frond. The indusium is present only in an early stage of 

 their growth ; it is white, and has an undivided margin. 



When this fern varies into a much more blunt form, 

 it constitutes the variety called by botanists ohtusum; 

 while sometimes, especially when growing in very 

 shady .places, it assumes a 'more slender and tapering 

 shape, and is called acutum ; both these forms are rare 

 in this country, though on the Continent they seem 

 well known, and are considered so permanent that they 

 are described as species. 



The French call the Spleenwort Doradille ; the ^qx- 

 mwa.s, Streifenfarren ; ihe.'DvLich., Miltkruid ; the Italians 

 ajid Spaniards, Asplenia. It is a common plant on 

 rockwork in gardens, and very well adapted to it ; but 

 its fronds do not become large unless it grows in shade. 

 It does not thrive so well in the closed case as in the 

 open air. 



3. A. fontdnum (Smooth Rock Spleenwort). — Frond 

 linear-lanceolate, twice pinnate ; pinna oblong, some- 

 what egg-shaped ; pinnules wedge-shaped and toothed. 

 This is a very rare fern, mentioned by our older botan- 

 ists as occurring on places on which it is no longer to 

 be found. It was described by Hudson as growing 

 near Wybourn, in Westmoreland. It also formerly grew 

 on the walls of Amersham Church, in Buckinghamshire. 

 It has of late years been found at Matlock, in Derby- 

 shire, on a very old wall at Tooting, also on a rock at 

 Stonehaven, and very recently by the Rev. W. H. 

 Hawker, growing in some quantity on a very old wall 



