POLYPODIACEAE. 



1. PHEGOPTERIS. Beech Fern. 



Medium sized or small ferns; leaves twice to thrice pinnate or 

 ternate; leaf-stalk continuous with the rootstock; fruit dots 

 small, round, without an indusium, borne on the backs of the 

 veins below <>r near their ends; veins free or reticulate. 



Phegopteris dryopteris (L.) Fee. Rootstock slender, horizontally creeping; 



petiole? 15-25 cm. tall, pale straw-colored, shiny, bearing a few brownish 



:, B toward the base; blades broadly triangular in outline, 10-20 cm. wide, 



nat< . t he lateral primary divisions bipinnate, the terminal usually tnpinnate, 



.,11 naked at the base; pinnae oblong, 2-5 cm. long, glabrous, pinnately-cleft 



or divided into 15-25 obtuse lobes; fruit dots near the margin, on the ends ot 



Common in rich woods. 



2. PTERIDIUM. 



1 .rge, mostlv coarse ferns, with variously divided leaves; 

 fruit dots marginal, linear, continuous on a slender thread-like 

 receptacle which connects the tips of free veins; false indusium 

 membranous, formed of the reflexed margin of the leaf. 



Pteridium aquilinum pubescens Undcrw. Bracken or Brake. Rootstock 

 stout, black, subterranean, horizontally-creeping; petioles 30-90 cm. high, 

 n or straw-color; leaf-blades 60-120 cm. long, 30-90 cm. wide, 

 glabrous above, pubescent beneath, ternate, the three branches each bipinnate; 

 pinnules oblong, acutish, mostly entire, the uppermost coalescent, the lower 

 more or less lobed. Common in coniferous woods, otherwise infrequent. 



3. PELLAEA. 



Small and smooth tufted rock ferns; leaves 1-4 times pinnate, 

 tin- petioles mostly dark colored; fruit dots terminal on the veins, 

 roundish but often confluent in a continuous band; false indusium 



intinuous, broad, formed by the reflexed margins of the pinnules. 



Pellaea densa (Brack.) Hook. Densely tufted, 10-20 cm. high; petioles 



d.irk brown, longer than the blades; blades 3-6 cm. long, ovate or ovate- 



oblong, tripinnate; ha Ikts crowded, linear-lanceolate, 6-12 mm. long, mucro- 



i in in- on the fertile leaves, serrate on the sterile ones. On cliffs and 



among boulders, Blue Mountains and top of Cedar Mountain, Idaho. 



4. CHEILANTHES. 



Mostly pubescent or tomentose rock-loving and small ferns 



th much divided leaves; fruit dots on or near the ends of the 



first small and distinct, afterwards crowded; sporangia 



n concealed in the scales or hairs which in many species 



er the segments. 



n ies occurring within our limits have the ultimate 



s of the pinnae very small and circular in form and the 



