564 THE FERN FAMILY. [Aspidium. 



districts of northern England. Fr. summer and autumn. Some 

 botanists regard this and the two preceding species as varieties of 

 A. Filix-mas, into which they appear (when seen growing in profusion) 

 to pass, through numerous intermediate forms. 



VIII. ASPLENIUM. SPLEEN WORT 



Fronds (in the British species) once, twice, or thrice pinnate or forked, 

 usually rather stiff, though slender, and often small. Sori oblong or 

 linear, on the under surface, usually diverging from near the centre 

 of the segments, covered when young by a membrane or indusium, which 

 opens outwards, being attached lengthwise along the outer side. 



Widely dispersed over the globe, and one of the most natural among 

 the large genera of Filices, for although a few of the larger species are 

 scarcely to be distinguished from some species of Aspidium and Poly- 

 podium, except by the sori, the great majority have a peculiar, dark 

 green, smooth appearance, which makes them easy to recognise. 



Fronds twice or thrice pinnate, with numerous primary pinnas, 

 the lowest or several lower pairs decreasing in size. 

 Frond 2 or 3 feet high, the longer pinnas 3 to 6 inches or 



more 1. A. Filix-foemina. 



Frond not a foot high, the longer pinnas seldom 1£ 

 inches. 

 Broadest part of the frond above the middle. Ulti- 

 mate segments 1 to 1| lines long . . . . 2. A. fontanum. 

 Broadest part below the middle. Ultimate segments 



broad, 2 to 3 lines long 3. A. lanceolatum. 



Fronds once pinnate, with numerous segments, the lower pairs 

 decreasing in size. 

 Segments thick, ovate, or lanceolate, J to 1 inch long or 



more 4. A. marinum. 



Segments thin, ovate or orbicular, under 5 lines long. 



Stalk black ... 5. A. Trichomanes. 



Stalk green 6. A. viride. 



Fronds more or less divided, the lowest pinnas larger, on 

 longer stalks, or more divided than the others. 

 Frond 6 inches to a foot, shining green, with numerous 



lanceolate pinnas and sessile segments . . . 7. A. Adiantum-nigrum. 

 Frond 3 or 4 inches, with a few small, stalked segments. 



Segments obovate 8. A. Ruta-muraria. 



Segments narrow-oblong 9. A. germanicum. 



Segments linear 10. A. septentrionale. 



1. A. Filix-fcemina, Bernh. (fig. 1295). Lady Fern. — A most elegant 

 Fern, with the short woody rootstock and circular tuft of fronds of 

 Aspidium Filix-mas, but more divided, the stalk less scaly, and the sori 

 different. Fronds usually 2 to 3 feet high, broadly lanceolate, twice 

 pinnate, the lower pairs of pinnas decreasing in size, the segments 

 oblong-lanceolate and pinnatifid, with pointed teeth. Sori shortly 

 oblong, diverging from the centre of the segments, with the indusium 

 attached along one side as in other Aspleniums, but shorter, and the 

 lower ones of the segment often slightly kidney-shaped, showing some 

 approach to those of Aspidium. Athyrium Filix-foemina, Bernh. 



In moist, sheltered woods, hedge-banks, and ravines, throughout 

 Europe and central and northern Asia, from the Mediterranean to the 

 Arctic regions, and in North America. Abundant in Britain. Fr. 



