POLYPODIACEAE. 3 



false indusia formed by the incurving of the whole of the leaf 

 margin. 



Leaf-blades glabrate above, bipinnate; ultimate segments 



mostly entire. C. gracillima. 



Leaf-blades pubescent above, tripinnate or tripinnatifid; ulti- 

 mate segments mostly crenate. C. feei. 



Cheilanthes gracillima D. C. Eaton. Lace Fern. Petioles densely tufted, 

 shining brown, 4-8 cm. high, bearing a few scattered lanceolate scales; blades 

 2-8 cm. long, oblong-lanceolate, bipinnate; pinnae numerous, crowded, pin- 

 nately divided into 5-9 oval mostly entire pinnules, glabrate above, pubescent 

 beneath with rusty matted wool. Common in rock crevices in the mountains. 



Cheilanthes feei Moore. Petioles densely tufted, 4-6 cm. high, brownish, 

 when young covered with long hair-like scales, at length glabrate; blades 4-8 

 cm. long, oblong-ovate, the lowest usually remote; ultimate segments orbicular 

 or oblong, entire or crenate, crowded; upper surface with a few long hairs, 

 the lower densely matted with whitish or pale-brown long hairs. Bluffs of 

 Snake River near Almota. 



5. 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 cyclosonim 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; 

 pinnae oblong-lanceolate, 5-20 cm. long; pinnules oblong, obtuse, obscurely 

 9-13-lobed, the lobes serrate; terminal pinnules confluent; fruit dots shorty 

 straight or curved. Common in moist woods. 



6. 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. 



Polystichum munitum (Kaulf.) Presl. 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. In deep woods of the Blue Mountains. 



7. WOODSIA. 



Small or medium sized ferns, growing in rocky places; leaves 

 once or twice pinnate or pinnatifid; fruit dots round, borne on 



