114 THE BRITISH FERNS. 
sometimes more obliquely cuneate there, thus becoming sub- 
trapeziform or rhomboidal, distant and usually opposite below, more 
crowded and alternate above, attached by a distinet slender stalk, 
the margin crenated or inciso-crenate, except at the cuneate base, 
which is entire. Occasionally the pinne are equal-sided and 
broadest at the base, much shortened and rounded at the apex; 
and sometimes they are more elongated and acute. 
Venation consisting of a costa or midvein, producing forked veins 
at the base of the pinnæ, and simple ones above. The veins and 
venules terminate abruptly within the margin, the point of termi- 
nation being marked by an elevation on the upper surface. 
Fructification more copious on the upper part of the frond, pro- 
duced on the anterior side of the vein; opposite the furcation and 
extending below it, if the vein is forked, and situated toward the 
base, that is, near to the costa, if the veins are simple. Sori linear 
oblique, indusiate, contiguous to the costa, and soon becoming 
confluent. Indusium narrow, crenated on the free margin. Spore- 
cases globose. Spores angular, rough. 
Duration.. The caudex is perennial. The fronds are produced in 
spring, and remain fresh through the winter, so that the plant is 
evergreen. 
Though similar to A. Trichomanes, and associated with it by some 
of our first botanists, this plant may be distinguished by its green 
compressed rachis, which is not prominent and rounded behind, nor 
furnished with a membranaceous border on the anterior face ; also by 
the more central situation of the sori, which are placed rather below 
than above the fork of the veins. It is, moreover, always of a much 
paler green colour, and has a more delicate herbaceous appearance. 
The Green Spleenwort is found principally in the moist moun- 
tainous rocky districts of the north of England and Scotland, widely 
dispersed, and of frequent occurrence in congenial situations, but not 
generally abundant. It is also not unfrequent in Wales, and is 
found in Shetland. More southern stations are reported in the 
provinces of the Severn, Trent, and Mersey; but in these it is very 
local. It has also been found located in somewhat dubious situations 

