CVSTOPTERIS. 197 



hdbiiing temperate climates both of the old and new world, 

 and both hemispheres. Fronds (jeneralhj small, delicate, 

 membranaceous, bi-lripinnatijid or pinnate. V^'ins pinnate 

 and forked, vcinlcts jOee, terminatina a little within the 

 margin. 



Obs. — A genus founded on the well-known C.frag'di.i, whose fructifica- 

 tion has been viewed by authors in very different lights, hence the copious 

 list of synonymous genera : and it must be confessed that the smallness of 

 the fructification, together with the very delicate succulent nature of the 

 involucre when fresh, membranous when diy, soon becoming revolute and 

 shrinking, has occasioned much of the difficulty. The few species which 

 it contains are found to be extremely variable, and they have been need- 

 lessly multiplied ; while on the other hand species have been added which 

 clearly have no connexion with it. Confined to its legitimate species it is 

 a very natural genus, and may assuredly be considered a connecting link 

 between the DavaUlavcce and Aspidiacrcr, harmonizing better with the for- 

 mer than with the latter, especially with that group, or subgenus, as it is 

 here called, of DavalUa, Leucostegia. The involucre forms a kind of cup at 

 the base, holding, as it were, in the young state, the sorus, and having a 

 broad point of attachment. On account of the affinity with Davalliu, I 

 place the genus between that and Lindscm, some of whose species, as has 

 been already intimated, bear also a close affinity to DavalUa. 



1. C. frag it is, Bernh.; fronds broad lanceolate bipinnale, 

 pinnae ovate or lanceolate variously toothed or laciniated or 

 pinnatifid the segments more or less acnte entire or again 

 toothed, sori scattered more or less distant sometimes crowd- 

 ed and almost confluent, rachis winged. 



a. vulgaris; Ironds decompound pale green, sori rather 

 large generally crowded, involucres usually acuminated 

 conspicuous. 



Cystopteris f'ragilis, Bernh. Neu. Journ. Bot. ii. p. 27. 

 Polypodium, L. Aspidium, Sw. Willd. Sp. PL v. p. 280. 

 Schkh. Fil. t. 54 {e.vcellent), and vars. tt. 55, 56. Cyathea, 

 Sm. Engl. Bot. t. 1587. Cyathea, Sm. Eng. Fl. iv. p. 289. 

 C. orientalis, Desv. 



Hah. (a.) Hocks and walls, chiefly in northern or alj)ine regions through- 

 out Europe. Kamtschatka, {Herb, iioslr.) Iceland, Hooker. Abyssinia, 

 Schimper. — N. America, from the middle slates to the Polar sea: among 

 the Rocky Mountains, and both on the Pacific and Atlantic sides of that 

 continent. Madeira, Mund {Herb. Carmichucl), Lowe and others). Nor- 

 thern India, Affghanistan, Griffith. Kaffre country. Cape of Good Hope, 

 Ecklon. 



The type of this species, which I here call a. vulyarii, is familiar to every 

 European botanist, and scarcely less common in moist mount<iin rocks iu 

 N. America ; but no one can have seen an extensive suite of specimens, 

 from the same or from different localities, without being aware of the va- 

 ried aspect it exhibits. In South America it assumes rather a different 

 character from the European plant, chiefly however depending on colour, 

 whence it may be called 



