THE OTHER BRITISH FERNS— POLTSTICHUM, ATHTRIUM, CETERACH 



'Athyrium flexile grows intermixed with A. alpestre amongst rocks in the north corrie of 

 Ben Alder from 2750 to 3400 ft. Matm^e plants of A. flexile are readily distinguishable by 

 their much smaller size — the fronds rarely exceed 6 in. in length — by the more distant 

 and usually deflexed pinnae with narrow-based pinnules and the distinctly narrower 



FLEXILE LADY FERN, {natural size of a large plant). 



Fig. 85. Newman's original illustration oi Athyrium flexile (1854). 



and more tapering fronds. When the rhizome is not too deeply embedded amongst 

 stones the very short stipes are bent over at their bases so that the fronds spread more 

 or less horizontally, further accentuating the difference in appearance between this 

 species and the invariably erect A. alpestre. These differences in habit and frond 



96 



