160 
BRITISH TERNS. 
bleakest rocks. Its roots penetrate so deeply that they 
are most difficult to extract. 
• The little Wall Rue seems to have a preference for 
the haunts of man, especially where he builds his fences 
of brick. The quaint dull green tufts cluster in the 
walls of our old tow r ns, establishing themselves uninvited 
in the most prosaic situations. But the fern has by no 
means forsaken its native wilds, as the limestone rocks 
of North Yorkshire can testify ; there, and in similar 
districts in other counties, the W r all Hue continues to 
adorn the old quarry and the frowning scar, and to deck 
the bridges over many a brawling stream. 
In olden times this fern was considered a remedy for 
coughs and scorbutic complaints, but all faith in its me- 
dicinal powers has died away. 
It is common in Britain, and throughout Europe and 
temperate Asia, also in North and South Africa, North 
India, Thibet, and United States. 
Very difficult of cultivation ; the best chance of natu- 
ralizing it in the fernery is to take the plants and the 
stones together, and build both into the rockwork. 
29. Asplenium Trichomanes* L. Common or 
Maiden-hair Spleenwort. 
Caudex short, thick, fibrous. Stems numerous, tufted, co- 
loured, glossy, only occupying a quarter the length of the frond. 
Fronds narrow, pinnate. Leaflets oval, blunt, dark green above, 
paler beneath, nearly sessile, serrated. Sori oblique, regular, 
oval. Involucres pale brown. 
The roots of this fern are black and wiry ; the caudex 
thick and massive, crowded with the stems of living 
fronds, and the remains of the stems of dead ones. The 
stems are deeply tinted with blackish-purple or red- 
