CANADIAN FILICINEJE. 199 



in dry or rocky woods. Rootstock very slender, widely creeping, slightly chaffy on its 

 newer parts and especially toward the advancing end, giving off but few rootlets ; stalks 

 usually exceeding the fronds and sometimes very much so, scattered, erect, very slender, 

 brittle, dark-colored and chaffy near the base but smooth and green above, stramineous 

 when dry ; fronds light green, very thin and delicate in texture, smooth, 3 to 12 inches 

 long by about the same or even a little greater breadth, ternate into stalked, widely spread- 

 ing, triangular, pinnate divisions ; middle division the broadest and symetrical, while the 

 lateral have the pinnae on the lower side the longest, often very markedly so ; pinnae ses- 

 sile and pinnatifid, or even on the middle division bi-pinnatifid ; ultimate segments entire 

 or toothed ; sori near the margin. 



Like the rest of the genus, P. Dryopteris is subject to but little variation. Stouter, tal- 

 ler, and more rigid forms, which are not uncommon, are described as var. ereclum by Law- 

 son in Can. Nat., Vol. I, p. 269. 



Common in all or nearly all rocky woodlands from Nova Scotia to British Columbia, 

 and extending northward to the Arctic Circle. Not one of the commonest ferns, but to be 

 met with in most localities in Nova Scotia. — Rev. E. H. Ball. Common in New Bruns- 

 wick. — Fowler. Common in Quebec. — Maclagan, D 'Urban, Provancher, Macoim, etc. Com- 

 mon in rocky parts of Ontario. — Billings, Macoun, Burgess, etc, Along the Canada Pacific 

 Railway north of Lakes Huron and Superior.— J. Fletcher. Common along Lakes Manitoba 

 and YVinnipegosis, and in the Riding, Duck, and Porcupine Mountains, Man. ; Rocky 

 Mountains, specimens over 12 inches wide. — Macoun. Echimamish River to Oxford 

 House, N. "W. Ter.,— jR. Bell. Rocky Mountains and Great Bear Lake, lat. 66°.— Hook., in 

 Fl. Br.-Am. British Columbia. — G. M. Dawson. 



4— P. calcarea, Fee, (Limestone Beech-Fern, Limestone Polypod), Eaton, Ferns of N. 

 A., II, 211. Underwood, Our Nat. Ferns, etc., 102. 



Ph. Robertiana, A. Braun. 



Ph. Dryopteris, Fee, var. Robertianum, Davenport. 



Polypodium Robertianum, Hoff, Lawson, Can. Nat., I, 270. 



Polypodium calcareum, Smith. 



Polypodium Dryopteris, var calcareum, Gray, Man., ed. 2nd, 590. 



This, being a more rigid, is a somewhat less graceful plant than P. Dryopteris. It is a 

 non-evergreen species, from 10 to 20 inches high, found growing on limestone rocks. 

 Rootstock slender, widely creeping, slightly chaffy especially at and toward the advanc- 

 ing end; stalks scattered, slender, glandular, chaffy and darkened near the base; fronds 

 herbaceous but rigid, minutely glandular, 4 to 8 inches long by nearly the same width, 

 ternate into stalked, pinnate divisions, the lateral of which have the inferior pinner some- 

 what longer than the superior ; pinnae sessile and pinnately lobed or divided ; ultimate 

 segments oblong, obtuse, crenately toothed, or, in very large specimens, again lobed ; sori 

 copious and submarginal. 



This fern is closely related to P. Dryopteris, but is distinguished by its glandular stalks 

 and fronds, its greater rigidity, and by its having smaller inferior pinnae on its lateral 

 divisions. 



Though long attributed to America, the Limestone Polypod was not clearly known 

 as a native until a few years ago, when it was collected on slaty rocks in eastern Minne- 



