3 



3. Pellaea densa (Brack.) Hook. 

 Oregon Cliff-brake. (Fig. 65.) 



Onvfhium dtnsnm Brack, Fil. U. S. Expl. 

 Pellaea densa Hook. Sp. Fil. 2: 150. 1858. 



Rootstock rather slender, chaffy with 

 blackish scales. Stipes densely tufted, 

 wiry, slender, light brown, 3'-o/ long; 

 leaves ovate or triangular-oblong in out- 

 line, i '-3' long, densely 3-pin nate, the seg- 

 ments 3"-6" long, linear, nearly sessile, 

 acuminate or mucronate, those of the fer- 

 tile leaves tapering at each end, with 

 narrowly recurved margins ; apices of the 

 rare sterile leaves sharply serrate, these 

 otherwise similar to the fertile ones. 



Mt. Albert, Gasp, Quebec. Also from 

 British Columbia to Wyoming and California. 

 Summer. 



POLYPODIACEAE. 



15. CHEILANTHES Sw. Syn. Fil. 126. 1806. 



Mostly pubescent or tomentose rock-loving and small ferns with much divided leaves, 

 the son terminal on the veins, at first small, ultimately more or less confluent Indusium 

 formed of the reflexed margin of the leaf, roundish and distinct or more or less conflu- 

 ent. Sporanges pedicelled, provided with an elastic ring which bursts transversely, often 

 much concealed in the scales or tomentum which covers the segments in many species. 

 [Greek, in allusion to the lipped indusia of some species.] 



About 65 species, of temperate and tropical regions. Besides the following, some 14 others 



occur in the western and southwestern parts of North America and one in Florida. 



Leaves nearly glabrous, 2-pinnate. i. C. Alabamensis. 



Leaves hirsute and glandular, not tomentose ; indusia not continuous. 2. C. lanosa. 

 Leaves more or less tomentose ; indusia mostly continuous. 



Leaves z'-g long ; stipes slender, at length nearly glabrous. 3. C. gracilis. 



Leaves 6'-ig long ; stipes stout, densely brown-tomentose. 4. C. totnentosa. 



i. Cheilanthes Alabamensis (Buckl.) Kunze. Alabama Lip-fern. (Fig. 66.) 



Pteris Alabamensis Buckl. Amer. Journ. Sci. 

 45 : 177- 1843. 



Cheilanthes Alabamensis Kunze, Linnaea, 20 : 

 4- 1847- 



Rootstock creeping, rather stout and 

 short, clothed with slender brown scales. 

 Stipes black, 3'-7' long, slender, wiry, 

 villous at least towards the base with rusty 

 wool ; leaves lanceolate in outline, glab- 

 rous, 2 / -io / long, z-pinnate ; pinnae numer- 

 ous, ovate-lanceolate, acuminate, very 

 short-stalked, the lowest usually smaller 

 than those above ; pinnules oblong or tri- 

 angular-oblong, mostly acute, often auricu- 

 late on the upper side at the base, more or 

 less toothed or incised ; indusia pale, mem- 

 branous, interrupted by the incising of the 

 pinnae. 



On rocks, Virginia to Alabama, west to Hli- 

 nois, Arkansas and Arizona. Aug.-Oct. 



