POLYPODIACEAE. 7 



Polystichum Ionchitis (L.) Roth. Holly Fern. Leaves densely tufted, 

 20-40 cm. long, very short stalked, pinnate; divisions broadly lanceolate, 

 auricled on the upper side, spinulose-dentate, 2-4 cm. long, the lowest ones 

 much shorter and triangular. 



In rocky places in the mountains. Alaska to Quebec, Colorado and Cal- 

 ifornia. Eurasia. 



Polystichum munitum (Kaulf.) Presl. Pacific Christmas Fern. Leaves 

 simply pinnate, 60-120 cm. long, forming a crown; petioles stout, chaffy with 

 numerous brown scales; rachis also chaffy; leaflets linear or lanceolate-linear, 

 acuminate, very sharply and often doubly serrate, sometimes chaffy on the 

 midvein beneath, 3-10 cm. long; fruit dots abundant, arranged in a row on 

 each side of the midrib half-way to the margin. 



Very common in the woods. Alaska to Idaho and California. 



Polystichum munitum imbricans (D. C. Eaton) Maxon. Like the species 

 but smaller, the leaves 20-40 cm. long; divisions much overlapping each other, 

 oblique to the rachis and cuspidate at the apex. 



Among rocks in the mountains at 1000 to 1700 m. elevation. British 

 Columbia to California, rather rare. 



Polystichum munitum inciso-serratum (D. C. Eaton) Maxon. Differs 

 from the species mainly in the leaflets being deeply incised and the lobes 

 serrate ; the base of the leaflets usually conspicuously auriculate. 



Rare, British Columbia to California. 



13. DRYOPTERIS. Shield Fern. 



Fruit-dots round, borne on the back or rarely at the apex of 

 the veins; indusium fiat or fiattish, heart-shaped and attached 

 at the middle of its sinus; veins nearly always free. 



Veins simple or once forked; leaves glandular. D. oreopteris. 

 Veins freely forking; leaves not glandular. 



Leaves bipinnate, thin and delicate. D. spinulosa. 



Leaves tripinnate, firm, half -evergreen. D. rig' ' 



Dryopteris oreopteris (Sw.) Maxon. Tufted; leaf -stalks short, scaly at 

 base; leaves bipinnatifid, broadly lanceolate, glandular, 60-90 cm. long; 

 ultimate segments oblong, nearly entire; indusia delicate, toothed on the mar- 

 gins. 



In the mountains, Alaska to Washington. Eurasia. Shawnigan Lake, 

 Vancouver Island, Macoun; Bridge Creek, Okanogan County, Elmer. Very 

 rare south of Alaska. 



Dryopteris spinulosa dilatata (Hoffm.) Underw. Wood Fern. A tufted 

 delicate fern; leaf-stalks 15-40 cm. long with slender dark brown scales; blades 

 tripinnate or tripinnatifid, broadly ovate in outline, 30-40 cm. long; ultimate 

 divisions oblong-lanceolate, the lowest ones longest, spinulose-toothed; 

 indusia minutely glandular ciliate. 



In rich woods, common. Alaska to Newfoundland, south to California, 

 Montana and Virginia. Eurasia. 



Dryopteris rigida arguta (Kaulf.) Underw. Leaf -stalks clustered; blades 

 firm, half-evergreen, 30-90 cm. long, ovate-lanceolate, bipinnate; ultimate 

 segments oblong, incised and spinulose; indusia bearing stalked glands. 



Principally in rocky places. Alaska to California, more common south- 

 ward. Victoria, Anderson; Sauvies Island, Oregon, Howell. 



