i6 



POLYPODIACEAE. 



Vol. I. 



6. POLYSTICHUM Roth, Romer's Arch. Bot. 2 1 : 106. 1799. 



Coarse and usually rigid erect ferns of harsh texture, with pinnatifid to quadripinnatifid 

 leaves borne typically in a crown upon a suberect or decumbent rootstock, the stipe not jointed 

 to it. Sterile and fertile leaves similar, the vascular parts usually chaffy; divisions of the 

 blade mainly auriculate and spinulose or mucronate, with free veins. Sori round; indusium 

 superior, orbicular, attached at its middle. [Greek, signifying many rows, in allusion to the 

 numerous regular rows of sori in P. Lonchitis (L.) Roth, the typical species.] 



About 100 species, of wide distribution, mainly in temperate regions. 



Leaves simply pinnate. 



Lower pinnae gradually much reduced; upper (soriferous) pinnae conform. 



1. P. Lonchitis. 

 Lower pinnae scarcely reduced; upper (soriferous) pinnae of fertile fronds contracted. 



2. P. acrostichoides. 

 Leaves bipinnatifid or bipinnate. 



Leaves coriaceous, the pinnae deeply lobed at their base. 3. P. scopulinum. 



Leaves herbaceous, fully bipinnate. 4. P. Braunii. 



i. Polystichum Lonchitis (L.) Roth. Holly-fern. Fig. 33. 



Polypodium Lonchitis L. Sp. PI. 1088. 1753. 

 Aspidium Lonchitis Sw. Schrad. Journ. Bot. 1800 2 : 30. 



1801. 

 Polystichum Lonchitis Roth, Rom. Arch. Bot. 2 1 : 106. 



1799. 

 Dryopteris Lonchitis Kuntze, Rev. Gen. PI. 813. 1891. 



Rootstock short, stout, densely chaffy. Stipes 

 l'-S' long, bearing large ferruginous scales with 

 smaller ones intermixed ; blades rigid, coriaceous, 

 evergreen, 6'-2° long, linear-lanceolate, once pinnate ; 

 pinnae numerous, close, broadly lanceolate-falcate, 

 l'-li' long, acute, strongly auricled on the upper 

 side at the base, obliquely truncate below, notably 

 spinulose-dentate, the lowest commonly triangular 

 and shorter; sori large, borne usually in two rows, 

 nearly equidistant between the margin and midrib, 

 subconfluent with age ; indusium entire. 



On rocks, Labrador to Alaska, south to Nova Scotia, 

 Ontario, Wisconsin, Montana and Washington, and in 

 the mountains to Utah, Colorado and California. Also 

 in Greenland, Europe and Asia. Called also' Rough 

 alpine fern. Aug. 



2. Polystichum acrostichoides (Michx.) Schott. Christmas-fern. Fig. 34. 



Nephrodium acrostichoides Michx. Fl. Bor. Am. 2 : 267. 



1803. 

 Aspidium acrostichoides Sw. Syn. Fil. 44. 1806. 

 Polystichum acrostichoides Schott, Gen. Fil. 1834. 

 Dryopteris acrostichoides Kuntze, Rev. Gen. PI. 812. 1891. 



Rootstock stout, creeping. Stipes $'-7' long, densely 



chaffy; blades lanceolate, i°-2° long, 3'-$' wide, rigid, 



evergreen, subcoriaceous, once pinnate; pinnae i's' 



long, narrowly oblong-lanceolate, somewhat falcate, 



acutish at the apex, half halberd-shaped at the base, 



with appressed, bristly teeth, the lower pinnae scarcely 



smaller, sometimes deflexed; fertile fronds contracted 



at the apex, the reduced pinnae soriferous, their under 



surface nearly covered with large contiguous sori in 2-4 



rows, confluent with age; indusium entire, persistent. 



In woods and on hillsides, most abundant in rocky 

 places, Nova Scotia to Ontario and Wisconsin, south to 

 Texas and the Gulf states. Ascends to 2700 ft. in Mary- 

 land. July-Aug. Called also Christmas shield-fern. 



Forms with cut-lobed or incised pinnae are known as 

 var. Schweinitzii; occasional forms are 2-pinnatifid. 



