THE RUE-LEAVED SPLEENWORT 
351 
in rocky crevices ; and the crumbling mortar and vegetable 
soil intermixed with it favour the growth of the Wall Rue, 
which is always found in greatest luxuriance on the loose 
tops of walls, where there has been necessarily the greatest 
accumulations of vegetable deposits. Sometimes loose walls 
and other loose stony structures are thickly covered with 
specimens of the Wall Rue, the little plants generally 
growing in an almost horizontal position, and seeking the 
protection for their crowns of some little jutting fragment of 
stone, their wiry rootlets being inserted into the moist seams 
between the stony masses. 
Description. — Though a small plant, Asplenium ruta- 
murciria has a somewhat thick, tufted, rootstock furnished 
with densely-crowded fibrous rootlets, occasionally so pressed 
and crowded together as to form quite a compact and 
almost solid mass. From this rootstock it throws up 
usually a considerable number of little fronds, mostly an 
inch or two long ; but occasionally, vdien growing under 
very congenial circumstances, reaching a length of five or 
six inches. In the smaller specimens, the stipes is usually 
about the same length as the leafy part of the frond, but in 
more luxuriant specimens the stipes is frequently double the 
length of the leafy part. The stipes is very slender and 
dark-green throughout, except at its extreme base, 'where it 
is somewhat blackish in colour. The upper part of the 
frond, like the stipes, is dark-green in colour, thick and 
leathery in texture, and shining. Its leafy portion is some- 
what triangular in shape and twice pinnate, sometimes in 
luxuriant specimens nearly three times pinnate in the lower 
part of the frond. The pinnae are placed alternately along 
and on opposite sides of the rachis. The lower pinnae are 
divided into two or three — generally three— stalked pinnules, 
which are of various forms, sometimes egg-shaped or pear- 
shaped, and then attached by their narrower ends, to the 
v 
