210 MACOUN AND BURGESS ON 



smooth above but chaffy below ; pinnae very numerous, crowded and often overlapping, 

 broadly lanceolate-falcate or the lower triangular, strongly auricled on the upper side 

 wedge-truncate on the lower, spinulose-serrate with pointless teeth between the serra- 

 tions ; sori confined to the upper part of the frond, placed about half way between the 

 midvein and margin, following the outline of the auricles as well as of the pinnae. 



This fern shows but little tendency to variation, the only noticeable differences being 

 in the size of the fronds and their coarser or finer serration. Occasionally, too, fronds are 

 seen oblaneeolate in outline, while from Europe they are reported as sometimes forking at 

 the apex, which teratological variation would probably also be found here if sought for. 



Found in North-eastern Nova Scotia, this fern is not seen again until it reappears in 

 Central Ontario, on leaving which it is again absent until the Eocky Mountains are reached, 

 although in the north it is reported in Hooker's Arctic Plants as being found on rocks along 

 the Arctic coast from the Mackenzie Eiver to Baffin Bay. In considerable abundance 

 near Aspey Bay, Cape Breton, N. S. — A. H. McKay. Found sparingly at Foster's Flats, 

 below the Whirlpool, Niagara Falls, Out. ; very common on rocky ground, especially 

 under cliffs, throughout the Bruce Peninsula, and around Owen Sound, Out. ; on the moun- 

 tain slopes of Bow Eiver Pass, Eocky Mountains, N. W. Ter., and in Peace Eiver Pass, 

 Eocky Mountains, Lat. 56° ; Cascade Mountains, above Yale, B. C. — Macoun. Kootanie 

 Pass, Eocky Mountains, about Lat. 49°, at 6,500 feet elevation. — G. M. Damon. Eocky 

 Mountains, Lat. 52 - 56°. — Drummond. 



f f Stalks at least several inches long, 



12. — A. acrostichoides, Swartz, (Christmas-Fern, Chaffy Shield-Fern), Syn. Fil., 44. 

 Gray, Man., 666. Hook, and Baker, Syn. Fil., 250. Pursh, II, 661. Provancher, Flor. 

 Can., "718. Macoun's Cat., No. 2313. Fowler's N. B. Cat., No. 759. Ball, Trans. N. S. Inst. 

 Nat. Sci., IV, 153. Eaton, Ferns of N. A., I, 257. Underwood, Our Nat. Ferns, etc., 102. 



Polystichum acrostichoides, Schott, Lawson, Can. Nat. I, 285. Watt, Can. Nat. IV, 363. 



Nephrodium acrostichoides, Mx., Fl. Bor.-Am, II, 267. 



A narrowly lanceolate fern with dark shining evergreen foliage, growing about 9 or 

 10 inches to 2i feet high in tufts in woods and on wooded hillsides, and especially favor- 

 ing rocky soil. The sterile and fertile fronds are somewhat dissimilar, the latter being 

 generally rather taller and more erect, with the upper fruit-bearing pinnae contracted and 

 smaller. Eootstock creeping and covered with old stalk-bases ; stalks green above but 

 brown at the base, chaffy especially below ; fronds leather}', lanceolate from a scarcely 

 narrowed base, 6 inches to 2 feet long bv 3 to 5 inches wide, smooth above but more or 

 less chaffy below, pinnate ; pinnae linear-lanceolate, the upper often more or less falcate, 

 short-stalked, abruptly narrowed at the lower side of the base and auricled above, serrulate 

 with appressed bristle-pointed teeth ; sori placed near the midvein, confluent, when ripe 

 covering the entire under surface including the auricles of most of the fruiting pinnae. 



Fronds with the pinnae incised-serrate are not very uncommon, and occasionally this 

 is carried so far that the pinnae are almost pinnatifid, making a form that stands interme- 

 diate between the typical plant and var. incisum, Gray. The latter has the pinnae cut 

 lobed, those of the fertile fronds being nearly or quite all fruit-bearing, with the sori gen- 

 erally covering the upper pinnae, but confined to the tips of the lower ones. Specimens 

 with forking fronds and pinnae have also been reported. 



