2 
POLYPODIACEAE. 
Sori linear or oblong, at least twice as long as broad. 
Sori marginal. 
Indusium present formed of the recurved leaf margin. 
Indusium double, the inner membranous one opening outwardly; leaves 
large, scattered. 7. Pteridium. 
Indusium single. 
Leaves dimorphous, the sporophyls contracted and more or less pod¬ 
like. 8. Cryptogramma. 
Leaves uniform or nearly so. 
Leaves chaffy or tomentose, the ultimate segments small and bead- 
like. 9. Cheilanthes. 
Leaves smooth with dark polished stalks; segments broader. 
10. Pellaea. 
Indusium wanting; under surface (in the Colorado species) with white pow¬ 
der; rachises zigzag. 11. Northolaena. 
Sori dorsal, oblique to the midribs or rachises, covered with a special in¬ 
dusium. 
Leaves pinnate or pinnately compound. 
Sori straight. 12. Asplenium. 
Sori curved, often crossing the veins; indusia occasionally horseshoe¬ 
shaped. 13. Athyrium. 
Leaves dichotomous, the divisions few and narrow; small rock-loving plants 
of the mountains. 14. Belvisia. 
1. POLYPODIUM L. Polypody. 
1. Polypodium hesperium Maxon. [P. vulgare of western botanists.] On 
rocks, Mont, to B. C., Wash., Colo, and Ariz.—Alt. about 8500 ft.—Red Moun¬ 
tain road, south of Ouray. 
2. PHEGOPTERIS Fee. Beech-Fern. 
1. Phegopteris Dryopteris (L.) Fee. In moist-rocky places; Newf. to 
Alaska, Ore., Colo, and Va.—Alt. about 8000 ft.—Green Mountain Falls. 
3. POLYSTICHUM Roth. Holly-Fern. 
1. Polystichum Lonchitis (L.) Roth. On rocks, Arctic America to N. S., 
Calif, and Colo.—Alt. 8500-10,000 ft.—Ruby; Red Mountain road, south of 
Ouray; Fish Creek Falls, Routt Co. 
4. DRYOPTERIS Adans. Male-Fern, Wood-Fern. 
1. Dryopteris Filix-mas (L.) Schott. On rocks, N. S. to northern Mich., 
Alaska, Calif., Ariz. and Colo.—Alt. 6000-8500 ft.—Red Mountain road, south 
of Ouray; Horsetooth Mountain; Canon City; Rist Canon. 
5. WOODSIA R. Br. 
Teeth of young leaves coarse, not ciliate. 
Stalks and pinnules covered with minute flattened hairs. 1. W. scopulina. 
Stalks and pinnules smooth. 2. W . oregana. 
Teeth of young leaves fine, ciliate at the tips. 3. W. mexicana. 
1. Woodsia scopulina D. C. Eaton. On exposed rocks, Mich, to B. C., 
Calif., Ariz. and Colo.—Alt. 5000-7000 ft.—North Cheyenne Canon; vicinity 
of Arthur’s Rock; Boulder; Horsetooth Gulch; gulch west of Soldier Canon; 
foot-hills, Larimer Co.; South Boulder Canon. 
