POLYPODIACEAE. 



Vol. I. 



i. Pteridium aquilinum (L.) Kuhn. Brake. 

 Bracken. Fig. 73. 



Pteris aquilina L. Sp. PI. 1075. 1753. 



Pteridium aquilinum Kuhn, in Decken's Reisen III. 



Bot. Ost.-Afrika 11. 1879. 



Stipe i°-3° long, straw-colored or brownish, rigid, 

 without chaff, swollen at the base. Blade 2°-4° 

 long, i°-3° broad, triangular to deltoid-ovate, usually 

 subternate, the long-stalked basal pinnae and the 

 middle ones 2-pinnate, those above 2-pinnate to 

 lobed or simple ; segments oblong to lanceolate, the 

 under surface glabrous or pubescent. 



In thickets or open situations throughout most of 

 North America. Ascends to 5000 ft. in North Carolina. 

 Aug. Nearly cosmopolitan. July-Sept. Earnfern, 

 Eagle-fern, Lady-bracken, Adder-spit, Hog-brake. 



The var. pseudocaudatum Clute, from Massachusetts 

 southward, has long linear pinnules, nearly simple. 



16. CRYPTOGRAMMA R. Br. App. 

 Franklin's Journ. 767. 1823. 



Small mainly alpine or boreal ferns with dimorphous leaves, the stipes greenish or straw- 

 colored, the blades 2-3-pinnate, the fertile exceeding the sterile. Sori borne at or near the 

 ends of the free forking veins, at length confluent. Indusia formed of the altered reflexed 

 margin of the segment. [Greek, alluding to the sori hidden before maturity.] 



Four species, the following and 2 of Europe and Asia. Type species : C. acrostichoides R. Br. 

 Rootstocks stout, clustered, ascending; fertile segments linear. 1. C. acrostichoides. 



Rootstocks slender, creeping ; fertile segments much broader. 2. C. Stelleri. 



i. Cryptogramma acrostichoides R. Br. 



American Rock-brake. Fig. 74. 



Cryptogramma acrostichoides R. Br. App. Frank- 

 lin's Journ. 767. 1823. 



Rootstock stout, short, chaffy; leaves clus- 

 tered, the fertile ones surpassing the sterile. 



Stipes 2'-6' long, chaffy below, those of the 



sterile leaves slender, greenish and of the fer- 

 tile stouter and stramineous; blades ovate or 



ovate-lanceolate, thin, glabrous, 2-3-pinnate, the 



sterile ones with the ultimate segments and 



pinnules crowded, ovate, oblong or obovate, 



obtuse, crenate or incised; fertile blades with 



segments 3"-6" long, 1" or less wide, the thin 



margins involute to the midrib at first, at 



maturity expanded, exposing the sporanges. 

 Among rocks, Labrador to Alaska, south to 



Lakes Huron and Superior, in the mountains to 



Colorado and California. Summer. 



2. Cryptogramma Stelleri (S. G. Gmel.) 

 Prantl. Slender Cliff-brake. Fig. 75. 



Pteris Stelleri S. G. Gmel. Nov. Com. Acad. 



Petrop. 12: 519. pi. 12. f. 1. 1768. 

 Pellaea gracilis Hook. Sp. Fil. 2: 138. 1858. 

 Cryptogramma Stelleri Prantl, Engler's Bot. 



Jahrb. 3 : 413. 1882. 



Rootstock slender, creeping, somewhat scaly. 

 Stipes scattered, 2-5' long, straw-colored or 

 pale brown, slightly chaffy below ; blades thin- 

 membranous, ovate or oblong-ovate, 2'-$' long, 

 1 '-2' wide; pinnae few, the lower nearly 2-pin- 

 nate, the middle pinnate, the upper simple; 

 segments of sterile blades ovate to obovate, 

 cuneate, crenately lobed, those of the fertile 

 linear-oblong or lanceolate ; indusium broad. 



On rocks, preferring limestone, Labrador to 

 Alaska, Pennsylvania, Iowa, Wisconsin and Colo- 

 rado. Also in Asia. Aug.-Sept. 



