THE ROCK SPLEENWORT 
365 
the centre, tapered to an acute point at the apex, and 
tapered down to its base by the gradual diminution of its 
pinnae — which] are set on sometimes in opposite pairs, and 
sometimes in alternation along on opposite sides of the 
rachis — until they become the tiniest of leafy expansions. 
The pinnae are somewhat bluntly triangular in shape, and are 
divided into somewhat quadrate or four-sided pinnules, which 
in their turn are very sharply indented or serrated, giving a 
spinulose or prickly appearance to the frond. Along on each 
side of the rachis, and also along on each side of the mid- 
stems of the pinnae, there extends a very slight leafy expan- 
sion or wing, so slight however as not to be readily seen without 
the aid of a glass in small specimens, but more readily distin- 
guished in larger fronds. The stipes is extremely short, and 
of a very dark purple colour, almost approaching black. The 
usual length of the fronds is four or five inches only, but under 
the influence of congenial conditions of growth, and in cultiva- 
tion 'when subjected to the moist heat of a hothouse, it attains 
a height sometimes of a foot. The colour of the fronds is a 
bright green ; their texture is thick and leathery. In the 
venation there is no very distinct mid- vein in the pinnules. 
A vein proceeds from the bases of the latter, and becomes 
branched — a branch or venule proceeding to each of the 
marginal teeth. Upon the venules are borne the sori, which 
are first covered — each sorus — by a somewhat short though 
oblong scale or indusium, which, as the spores ripen, is thrown 
off and disappears. As in Lanceolatum the sori mostly keep 
distinct from each other. But they not unfrequently become 
confluent, and they then almost completely cover the under 
side of the pinnules. Five or six varieties of the normal form 
have been found. 
Distribution. — Asplenium fontcinum ranges through the 
following countries of Europe, namely, Belgium, France, 
Germany, Greece, Hungary, Italy, Spain, and Switzerland. 
