

258 THE BRITISH FERNS. 
the fructification may be seen lying hood-like over the roundish 
masses of spore-cases. It is a plant so polymorphous in character 
that the species which botanists have from time to time endeavoured 
to separate from it, though sometimes assuming a distinct-looking 
aspect, appear in other cases to become united by intermediate 
forms, and are then with difficulty defined even as varieties. 
Cystopteris fragilis must indeed be considered as being, like the 
still more polymorphous Athyrium Filix-femina and Lastrea dilatata, 
a botanical ignis fatuus, alluring the incautious novelty-seeker 
among the quagmires of species-making, in which, at length when 
his mental vision becomes cleared by more extended observations, 
he finds himself hopelessly floundering. 
This small and elegant herbaceous annual-fronded species is widely 
distributed, occurring here and there over the whole of Great Britain. 
It is most abundant among the hills and mountainous tracts of the 
north of England and of Wales; and becomes somewhat rare in 
the south and south-eastern parts of the island. It is found how- 
ever, in the extreme south of England, and extends in Scotland 
northwards to the Hebrides and the county of Sutherland, ascend- 
ing, in the east Highlands, to an elevation of more than 3000 feet 
above the sea. It generally occurs growing in the fissures of moist 
shady rocks, or of masonry. In Ireland, though here and there 
abundant, it seems less generally distributed. The chief recorded 
habitats are as follows :— 
Peninsula.—Devonshire: Exwick, near Exeter; since reported 
to be only a seedling of Athyrium Filix-femina; near Ilfracombe, 
Rev. J. M. Chanter ; limestone rocks near Torquay, very rare. 
Somersetshire : Cheddar Cliffs, Sir W. C. Trevelyan, Bart.; Hamp- 
ton Cliffs, Bath, R. Withers, &c. ; abundant. 
Channel.—Dorsetshire. Wiltshire: Box Quarries, abundant, 
E. Newman. Sussex: Tunbridge Wells. j 
Thames.- Surrey : Albury, T. M. 
Ouse. Suffolk: Yoxford; Bungay, D. Stock. Norfolk, S. P. 
Woodward. Northamptonshire. 
Severn.—W arwickshire: near Arbury Hall; Leamington, Dr. 

