148 BRITISH FERNS. 
intermediate in habit and form, and will be reputed 
a variety of either by those who are unacquainted with 
European species. 
39. RUE-LEAVED SPLEENWORT. Rura-mugarta. 
WALL RUE 
Asplenium Ruta-muraria, Linneus. B. F. 258, 266. 
The caudex is black, tufted, and clothed with bristly 
scales: the fronds make their appearance in May or 
June, arrive at maturity in September, and continue 
_ perfectly green throughout the winter, and until the 
radiate from the stalk to the outer edge of the pin- 
nule, and to them are attached the elongate lines of 
seeds, two, three, four and even five on a pinnule: 
these are at first covered by an elongate, linear, white 
- involucre, the free margin of which generally faces 
the median line of the pinnule, and is jagged and 
uneven; this is soon pushed aside by the swelling 
