18 
BRITISH FERNS. 
Frond once-pinnate , with numerous segments , the lower pairs decreasing 
in size. 
Segments thick, ovate or lanceolate, £ to I inch long or more. 
Asplenium marinum. 
Segments thin, ovate or orbicular, under 5 lines long. 
Asplenium Trichomanes. 
Fronds more or less divided , the lozvest 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. 
Asplenium Adiantum nigrum. 
Frond 3 or 4 inches, with few small, stalked segments. 
Segments obovate .. .. .. Asplenium Ruta-muraria. 
Segments narrow-oblong .. .. Asplenium germanicum. 
Segments linear .. .. Asplenium septentrionale. 
