Plate 23. 
OYSTOPTEBPS eeagilis, Bernh. 
Brittle Bladder-Bern. 
Gen. Char. Sori subglobose. Involucre ovate, cucullate at the base, 
having its origin beneath the sorus, generally acuminate at its extremity. 
Cystopteris fragilis ; caudex creeping, elongated, very paleaceous towards the 
apex, with pale-brown, lanceolate, copious, very membranaceous scales ; sti- 
pites copious, approximate, slender, brittle, scaly near the base; fronds lan¬ 
ceolate, very membranaceous, bipinnate (rarely pinnate, with the pinnse 
deeply pinnatifid) ; pinnse deltoideo-ovate, acuminate; pinnules ovate or 
ovate-lanceolate, variously toothed or laciniate or pinnatifid, the segments 
entire or sharply lobato-serrate ; rachis winged. 
a. vulgaris ; fronds broad-lanceolate; pinnules subpetiolate, ovate, obovate or 
lanceolate, somewhat cuneate at the base, incise or pinnatifid; segments 
toothed; sori generally crowded, at a distance from the margin. 
Cystopteris fragilis. Bernh. N. Journ. Bot. v. 1. part 2. p. 27. t. 2. /. 9. 
Hook. and Am. Brit. FI. ed. 8. p. 197. Hook. Gen. Ml. t, 52 B ; Sp. Ml. 
v. 1. p. 197. Brest, Tent. Bterid. p. 93. t. 2>.f. 1. Moore , Brit. Ferns , 
Nat. Print, pi. 46 A. 
Polypodium fragile. Linn. Sp. PI. p. 1558. Bolt. Fit. p. 50. t. 27 and 46. 
Aspidium fragile. Sw. in Schrad. Journ. 1800, v. 2. p. 40. Syn. Fil.p. 58. 
Willd. Sp. PI. v. 5. p. 280. Schk. Fit. p. 53. t. 54-56 (very good, including 
several forms). 
Cyathea fragilis. Sm. Auct. Taur. 5417 ; FI. Brit.p. 1139 ; Engl. Bot. t. 1587. 
Cystea fragilis. Sm. Engl. FI. v. 4 . p. 298. 
(Subvar. angustata.) 
Cystea angustata. Sm. Engl. FI. v. 4 . p. 301. Forst. inE. Bot. Suppl. t. 2790. 
Cystopteris dentata, (3. Hook. Brit. FI. ed. 2. p. 443. 
Cyathea fragilis, ft. Sm. FI. Brit.p. 1139. 
Polypodium rhseticum. Dicks. H. Sicc. Ease. 1 . p. 17. 
(3. dentata ; fronds subbipinnate, pinnse ovato-lanceolate, pinnules sessile, ovate 
or oblong, obtuse, bluntly and unequally toothed, rarely pinnatifid, sori sub¬ 
marginal ; (intermediate between the common form and var. y). 
Cyathea dentata. Sm. Engl. Bot. t. 1558. 
Cystea dentata. Sm. Engl. FI. v. 4 .p. 300. 
Cystopteris dentata. Hook. Brit. FI. ed. 5 . p. 441. 
Polypodium dentatum. Dicks. Crypt. Fasc. 3. p. 1. t. 7. 
Aspidium dentatum. Sw. Syn. Fil.p. 59. 
Aspidium Pontederae. Willd. Sp. PI. v. 5. p. 278. 
y. Dickieana., Moore; fronds ovate-oblong, obtuse, very delicate, pinnate or sub- 
