666 THE FERN FAMILY. [Atplenivm. 



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 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 

 Europe and western and central Asia, extending northwards to southern 

 Scandinavia. Common in Britain. Fr. aU 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 

 oearing 3 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 ivhole season. 



9. A. germanicum, Weiss, (fig. 1303). German 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. Son few, long and narrow. A. alternifolium, 

 Wulf. 



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. 1304). 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. 



On rocks and old walls, in the mountainous districts of the greater 



