566 THE FERN FAMILY. [A splenium, 
on a garden wall at Newry, is almost certainly a hybrid with A, Ruta- 
muraria. | 
6. A. viride, Huds. (fig. 1300). Green S.—Very near A. Trichomanes, 
and considered in the first edition of this Handbook as a variety of it. 
It is usually less rigid, the segments rather shorter and broader 
especially on the upper side, and the stalk is either entirely green or 
brown at the base only. 
Among rocks in the mountains of central and northern Europe, Asia, ~ 
and America. Not uncommon in most mountainous districts of Britain, 
Fr. the whole season. 
7. A. Adiantum-nigrum, Linn. (fig. 1301). Black S.—Fronds 
tufted, usually 6 inches to a foot high, including the rather long, 
dark-brown or black stalk, the leafy part triangular or broadly lanceo- 
late, of a dark. shining green, and firm consistence, twice pinnate, or 
the lower part three times; the pinnas gradually decreasing and less 
divided, from the lowest pair to the point ; the segments varying from 
lanceolate to ovate or even obovate, sharply toothed or cut. Sori 
narrow-oblong or linear, sometimes, when old, covering nearly the 
whole surface. 
On sandy hedge-banks, rocks, and old walls, in central and southern 
Hurope and western and central Asia, extending northwards to southern 
Scandinavia. Common in Britain. Fr. all summer and autumn, . 
8. A. Ruta-muraria, Linn. (fig. 1302). Wall-Rue.—Fronds densely 
tufted, usually 2 to 3 inches long, rather dark-green, but not shining ; 
the stalk more or less pinnately divided; the lower pinnas usually 
bearing 8 segments, the upper ones simple ; the segments all stalked, 
obovate or broadly oblong, seldom above 2 lines long, and usually 
minutely toothed. Sori shortly linear, becoming united into broad 
patches when old. 
On old walls and rocks, throughout Europe and central and Russian 
Asia, except the extreme north, and in North America. Common in 
Britain, except in some of the eastern districts. Fr. the whole season. 
9. A. germanicum, Weiss. (fig. 1803). German S.—Very near A. 
Ruta-muraria, and perhaps a variety; but the segments are much 
narrower, usually narrow wedge-shaped or oblong, on short stalks ; the 
whole frond narrow, usually simply pinnate, with the lower segments 3- 
lobed, or very rarely bearing 3 distinct segments; the segments entire or 
toothed at the summit. Sori few, long and narrow. A. alternifolium, 
Wulf. é | 
On rocks and old walls, dispersed over the greater part of Europe, 
from Spain to Scandinavia, and in the Himalaya and China. Has 
been found in isolated localities in western and northern England 
and central and southern Scotland. Fr. summer and autumn. 
10. A. septentrionale, Hoffm. (fig. 1804). Forked S.—This again 
is allied to A. Ruta-muraria, and has similar tufted fronds, 2 to 5 or 
6 inches high; but the whole frond usually consists of a stalk, forked 
towards the top, each branch bearing a single, linear, entire or 2-lobed 
segment, about half an inch long, the linear sori occupying the whole 
under surface except the narrow pointed extremity. Some fronds have 
but a single entire or 3-lobed terminal segment, and a few have 3 
distinct segments. he 
On rocks and old walls, in the mountainous districts of the greater — 
