6 POLYPODIACEAE. 



10. ASPLENIUM. Spleenwort. 

 Fruit dots oblong or linear, oblique, separate; indusium straight, 

 attached to the upper side of the vein; veins free. 



Rachis of the leaf brown; leaflets oval, slightly crenate. A. trichomanes. 



Rachis of the leaf green; leaflets ovate, deeply crenate. A. viride. 



Asplenium trichomanes L. Common Spleenwort. Leaf-stalks tufted, 

 dark-brown, shiny; blades simply pinnate, linear in outline, 6-20 cm. long; 

 leaflets oval or oblong, unsymmetrical, obscurely crenate, 15-30 pairs, firm 

 and evergreen, with a brown rachis. 



Mossy rocks, rare in our limits. Alaska to Arizona. Widely distributed 

 in the Northern Hemisphere. 



Asplenium viride Huds. Much like A. trichomanes, but the thinner 

 paler leaflets deeply crenate and the rachis of the leaf green. 



Mount Baker, Washington, Flett; Ucluelet, Vancouver Island, British 

 Columbia, Macoun. A rare but widely distributed fern. Alaska to Washing- 

 ton, Colorado and New England. Eurasia. 



11. ATHYRIUM. 



Large or small ferns with simple, lobed, 2-3-pinnate or pin- 

 natifid leaves; fruit dots oblong or linear (nearly round when 

 young), oblique, separate; indusium more or less curved, some- 

 times horseshoe-shaped, often crossing to the outer or lower side 

 of the vein; veins free. 



Athyrium cyclosorum Rupr. Rootstock creeping, short, densely covered 

 by the bases of the petioles; petioles tufted, 20-30 cm. long, straw-colored or 

 brownish; blades delicate, glabrous, broadly oblong-lanceolate or oblong- 

 ovate, acuminate at the apex, 30-90 cm. long, bipinnate to tripinnatifid; 

 •leaflets oblong-lanceolate, 5-20 cm. long; ultimate segments oblong, obtuse, 

 obscurely 9-13-lobed, the lobes serrate; terminal segments confluent; fruit 

 dots short, straight or curved. 



In swampy places, common. Very similar to the more eastern Lady-fern, 

 A. filix-foemina. Alaska to Arizona and Nebraska. 



12. POLYSTICHUM. 



Large or medium sized ferns, mostly with firm evergreen leaves, 

 pinnate, bipinnate or bipinnatifid, the leaflets serrate and usually 

 auricled at the base on the upper side; veins free; indusium 

 orbicular and peltate, depressed in the center and attached by a 

 stalk to the middle of the fruit dot; fruit dots round. 



Leaflets, at least the lower ones, lobed. P. scopulinum. 



Leaflets all simple. 



Leaf-stalk short; segments triangular or broadly lanceolate. P. lonchitis. 



Leaf-stalk long; segments linear-lanceolate. P. munitum. 



Polystichum scopulinum (D. C. Eaton) Maxon. Leaves lanceolate in 

 outline, short-stalked, 15-25 cm. long; divisions ovate, obtusish, serrate, the 

 lower ones usually pinnately lobed. 



In loose rocks in the mountains, rare. Eatonville, Flett; Mount Adams, 

 Henderson. Washington and Idaho to California and Utah. 



