210 MACOUN AND BUEGESS ON 



smooth above but cbaffy 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, spiuulose-serrate with pointless teeth between the serra- 

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

 mid vein and margin, following the outline of the auricles as well as of the pinnœ. 



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

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

 seen oblanceolate 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.— ^. H. McKay. Found sparingly at Foster's Flats, 

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

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

 tain slopes of Bow River Pass, Rocky Mountains, N. W. Ter., and in Peace River Pass, 

 Rocky Mountains, Lat. 5G' ; Cascade Mountains, above Yale, B. Qi.—Macoim. Kootauie 

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

 Mountains, Lat. 52"- 56°. — Dnimmond. 



1 1 Stalks at least several inches long. 



12.— A. ACROSTICHOIDES, Sioartz (Christmas-Fern, Chaffy Shield-Fern), Syn. Fil., 44. 

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

 Can., V18. Macoun's Cat., No 2313. Fowler's N. B. Cat., No. TSQ. Ball, Trans. N. S. Inst. 

 Nat. Sci., IV, 153. Eaton, Ferns of N. A., I, 2b1. Underwood, Our Nat. Ferns, etc., 102. 



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



Nephrodium acrostichoides, Mx., Fl. Bor.-Am., II, 26*7. 



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

 10 inches to 2| 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 pinnœ contracted and 

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

 brown at the base, chaffy especially below ; fronds leathery, lanceolate from a scarcely 

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

 less chafiy below, pinnate ; pinnœ 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 pinnœ. 



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

 is carried so far that the pinnœ are almost piunatifid, making a form that stands interme- 

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

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

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

 with forking fronds and pinnœ have also been reported. 



