38 



species of herbaceous plants ; requiring only the occasional re- 

 moval of its rapidly maturing fronds to maintain the lively green 

 appearance of the masses throughout the summer. The delicate 

 feathery character of the foliage renders it a favourite species for 

 pot culture, and in a cool greenhouse it becomes highly ornamental ; 

 but it is not well adapted for planting in closed cases, though often 

 recommended for the purpose, the slender rachis being too rapidly 

 extended in the damp confined atmosphere to support the length- 

 ened frond, while the attacks of mildew and other fungoid pests, 

 to which it is liable under confinement, often prove fatal to the 

 other species in its vicinity. 



All of the British species or varieties of Cystopteris are seen, 

 under cultivation, to the greatest advantage when planted on 

 shaded rock-work : like other rock and wall plants, they require 

 good drainage, a condition readily effected by the admixture of 

 about one-fourth of small fragments of old mortar with the soil 

 or compost employed ; the value of this addition is farther indi- 

 cated by the natural preference they seem to evince for limestone 

 districts. 



CYSTOPTERIS DENTATA. Toothed Bladder-Fern. TAB. XXI. 

 XXII. 



Fronds oblong-lanceolate, bipinnate: pinnules ovate-obtuse, 

 bluntly toothed. Sori submarginal. 



Cystopteris dentata, Hooker, Brit. Fl. E. B., 2nd ed. Cyathea 

 dentata, Smith, Flora Brit. Cystea dentata, Smith, Eng. 

 Flora. E. B. 1588. Cystopteris fragilis, var. dentata, 

 Moore, Handb., ed. 2, 76. 



Not unfrequent in the rocky parts of Wales, Scotland, and the 

 North of England, though very liable to be passed over as a form, 

 of C. fragilis, with which most modern botanists indeed seem 

 inclined to confound it. The present is, however, in maturity a 

 smaller plant, differing considerably in the general outline of the 

 frond, and in the form, division and arrangement of the pinnae, 

 which are so placed, that their upper faces, instead of being vertical, 

 tend more or less towards a horizontal position ; this character is 

 difficult to express by figure, where, as in the ordinary state of the 

 fern, the pinna3 are distant, but it will be understood by reference 

 to Tab. XXII., representing an assumed variety, C. Dickieana. The 

 pinnules vary in division according to the luxuriance of the frond, 

 being deeply toothed, or, rarely, pinnatifid, but the teeth or seg- 

 ments are always remarkably obtuse, without the slightest ten- 

 dency to become pointed at the extremity. The sori, produced at 



