132 - FILICES 
are triangular and alternate ; the lower being deeply lobed and serrated at 
the margin. 
The fronds of the Black Spleenwort are not crisp and brittle, like those 
of many ferns, but have a tough and leathery texture, and are much veined. 
The winding mid-vein of each pinnule is very distinct, and from it issue 
veins which are either simple or forked ; one of these lesser veins extending 
to each point of the serrated margin, and bearing the cluster of capsules. 
The same mode of veining is apparent also in the ultimate divisions of the 
frond, as well as in the larger lobes, and these bear the -clusters near the 
point at which they unite with the mid-vein, so that the clusters are placed 
near the centre of every pinnule or lobe. In an early state the clusters are 
distinct, and are long and narrow; but as they mature, they form one dark- 
brown thick mass, almost covering the whole of the under 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 obtuswm, which is found growing on serpentine 
rocks in Aberdeenshire ; while sometimes, especially when growing in very 
shady places, it assumes a more slender and tapering shape, and is called 
acutum ; this has been recorded from South-west Ireland. Both these forms 
are rare in this country, though on the Continent they seem well known, 
and are considered so permanent that they are sometimes described as 
species. 
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. Smooth Rock Spleenwort (4. jfonténwm).—Fronds linear-lanceo- 
late, twice pinnate ; pinne oblong, somewhat egg-shaped ; pinnules wedge- 
shaped and toothed. This is a very rare fern, mentioned by our older 
botanists 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 Derbyshire, on a very old 
wall at Tooting, also on a rock at Stonehaven, and more recently by the 
Rey. W. H. Hawker, growing in some quantity on a very old wall near 
Petersfield, in Hampshire. It has been regarded as a doubtful native, and 
this doubt has been made almost a certainty by the fact that it has only 
been found in such situations as would suggest that it had been planted 
there at some previous date, or that its spores had been blown thence from 
garden specimens. 
It is not infrequent in Continental countries, in rocky places. This 
Spleenwort is a very distinct and handsome little fern, its thick rigid fronds 
growing in small tufts to the height of three or four inches. The upper 
surface of the frond is deep green, but the under part is of a pale whitish 
green, and it retains its colour throughout the winter. The outline of the 
frond is narrow lanceolate, the stalk very short and scaly at the base. It is 
twice pinnate, the pinne being oblong egg-shaped, and the pinnules inversely 
egg-shaped, somewhat wedge-shaped, tapering towards the base, and toothed 
