CANADIAN FILICINE.E. 213 



Genus XV— CYSTOPTEKIS, Bernh., Bladder-Fern. 

 * Fronds ovate-lanceolate, bi-tripinnate. 



1.— C. fragilis, Bernh., (Brittle-Fern), Gray, Man., 661. Provancher, Flor. Can., 719. 

 Lawson, Can. Nat., I, 286. Hook, and Baker, Syn. Fil., 103. Maconn's Cat., No 2322. 

 Goode, Can. Nat., IX, 299. Fowler's N. B. Cat,, No. 762. Ball, Trans. N. S. Inst. Nat. Sci., 

 IV, 154. Eaton, Ferns of N. A., II, 49. Underwood, Our Nat. Ferns, etc., 108. 



C. tenuis, Desv. 



Polypodium fragile, L. 



Aspidium tenue, Swartz, Syn. Fil., 58. Pursh, II, 665. 



Aspidium fragile, Swartz, Syn. Fil., 58. 



Nephrodium tenue, Mx., Fl. Bor.-Am., II, 269. 



Cyathea fragilis, Smith. 



Cystea fragilis, Smith, Watt, Can. Nat., IV. 303. 



This is a slender, common, and variable species, most at home in crevices of moist 

 shaded rocks and among stones, but also found in rich woods and sometimes in open wet 

 places. Its usual height is about 8 to 16 inches, though occasionally, in favored localities, 

 it reaches even as much as 2 feet, while in mountainous districts, depauperated forms not 

 exceeding 2 to 4 inches occur. It is non-evergreen, being very sensitive to frost. Poot- 

 stock elongated, creeping, covered with old stalk-bases, and very chaffy toward the apex ; 

 stalks slender, clustered, very brittle, straw-color or brown shading to green in the rachis, 

 darkest at the base where also they are sparingly chaffy ; fronds mostly reclining, oblong- 

 lanceolate or ovate-lanceolate, commonly 4 to 8 inches long by 1 to 3 wide, thin, smooth, 

 bipinnate; pinna ovate-lanceolate or somewhat triangular, pointed; pinnules decurrent 

 along the narrowly winged secondary rachis, ovate-oblong, somewhat acutely toothed or 

 shallowly incised and toothed ; sori small, roundish, usually distinct ; veinlets mostly 

 running out to the teeth of the lobes ; indusia acute at the free end. 



This fern is extremely variable, and the same roots will at different times or even the 

 same time produce fronds that might be referred to different ones of the numerous so-called 

 varieties, of which the following are perhaps the best known : — Var. dentata, Hook., with 

 narrow scarcely bipinnate fronds, less pointed pinna 1 , and obtuse merely bluntly toothed 

 ovate pinnules. Var. angustata, Smith, with broad and often nearly triphmate fronds, acute 

 pinna, and acute lanceolate pinnules, which have sharp toothed, sharply pointed lobes. 

 Var. laciniata, Davenport, with narrow and little more than pinnate fronds and ovate pinna, 

 the lobes of which are irregularly laciniate with narrow teeth. Var. McKayii, Lawson, a 

 common form in America, differing from the ordinary European plant (also found with us), 

 which has broad, leafy, approximate pinnae, in having the pinnae very far apart and nar- 

 rowly lanceolate ; pinnules oblong, always more or less cuneate at the base, and rounded 

 at the apex ; sori few and scattered ; plant when growing with a hard, bare look and a 

 bluish-green colour. A very peculiar form found at Whycocomagh, N. S., falls under var. 

 mtihifida, Wolleston. It resembles var. angustata in general appearance, but has the ends of 

 the fronds as well as most of the pinna and some of the pinnules forked or showing a 

 tendency thereto. Another form, in some respects approaching var. Dickieana, Sim., from 

 near Michipicotin on the north shore of Lake Superior, is broadly triangular-lanceolate in 

 outline, and has the pinnules overlapping one another, those of the lowest pinna remark- 



