CANADIAN FILICINI^.-E. 213 



aeniTs XV.— CYSTOPTERIS, Bernh., Bladdek-Fern. 

 * Frouds OA^ate-lanceolate, bi-tripiunate. 



1. — C. FRAGiLis, Bernh., (Brittle-Fern), Gray, Man., 667. Provaiieher, Flor. Cau., 719. 

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

 Goode, Cau. 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. 



Poll/podium 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. 



Ci/athea fragilis. Smith. 



Cystea fragilis, Smith, Watt, Cau. Nat., IV. 363. 



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 occi^r. It is non-CA^ergreen, being very sensitive to frost. Root- 

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

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

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

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

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

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

 shallowly incised and toothed ; sori small, roundish, visually 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 frouds that might be referred to different ones of the numerous so-called 

 varieties, of which the following are perliaps the best known : — Var. deidata. Hook., with 

 narrow scarcely bipinnate frouds, less pointed pinna>, and obtuse merely bluntly toothed 

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

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

 Var. laciniata, Davenport, with narrow and little more than pinnate frouds and ovate pinucT-, 

 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 piuna\ in having the pinnœ very far apart and uar- 

 roM'ly 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. 

 muUifida,^ oMenio-a. It resembles var. angustata in general appearance, but has the ends of 

 the fronds as well as most of the pinnœ aud 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 pinnœ remark- 



