38 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



12. Cheilanthes wootoni Maxon, Biol. Soc. Wash. Proc. 31: 146. 



1918. 

 Clear Creek (Coconino or Navajo County), and mountains of 

 Yavapai, Graham, Gila, Pinal, Cochise, Santa Cruz, and Pima 

 Counties, 3,000 to 6,500 feet, rock ledges and among boulders; com- 

 mon. Oldahoma, southeastern Colorado, and western Texas to 

 Arizona and northern Mexico (Sonora). 



13. Cheilanthes fendleri Hook., Sp. Fil. 2:103. 1852. 



Slate Mountain (Coconino County), Hualpai Mountain (Mohave 

 County), to the mountains of Cochise, Santa Cruz, and Pima Counties, 

 4,000 to 8,000 feet, dry rocky slopes and cliffs. Western Texas to 

 Colorado and Arizona. 



14. Cheilanthes pringlei Davenp., Torrey Bot. Club Bui. 10: 61. 



1883. 



Cheilanthes sonorensis Goodding, Muhlenbergia 8: 92. 1912. 



Mazatzal Mountains (Gila County), Chiricahua Mountains (Cochise 

 County), Baboquivari Mountains (Pima County), 3,000 to 5,000 feet, 

 at base of cliffs. Known only from Arizona, the type collected by 

 Pringle in 1883, and northern Mexico. 



16. PELLAEA. Cliffbrake 



Kather small, rock-inhabiting ferns, with erect, nearly glabrous 

 foliage; fronds uniform, the blades 1- to 4-pinnate; segments cori- 

 aceous, varying in shape and size ; veins free ; sori terminal on the veins, 

 laterally confluent in a broad intramarginal line, usually concealed at 

 first by the reflexed or revolute, continuous, indusiform margin, the 

 border modified or not. 



Key to the species 



1. Rhizomes cordlike, creeping, often widely so; stipe and rachises buff or pale 



brownish 1. P. intermedia. 



1. Rhizomes thick, multicipital ; stipe and rachises castaneous to atropurpureous 



(2). 

 2. Scales of rhizome concolorous, light to dark ferruginous (3). 



3. Blades once pinnate, or the basal pinnae sometimes ternately cleft or 

 divided at base; rachises smooth 2. P. suksdorfiana. 



3. Blades bipinnate nearly throughout; rachises scabrous. 



3. P. ATROPURPUREA. 



2. Scales of rhizome bicolorous, i. e., with a sharply denned, linear, blackish 

 median stipe (4). 



4. Blades triangular-ovate; pinnae with 6 to 10 pairs of segments, these 



sessile or short-stalked, articulate, grayish-pruinose. 



4. P. LONGIMUCRONATA. 



4. Blades linear to narrowly lanceolate; pinnae ternately divided or with 1 

 to 4 pairs of semiadnate or sessile segments (5) . 

 5. Stipe and rachis castaneous; pinnae commonly with 2 or 3 pairs of 

 spaced segments or, if ternately divided, the apical segment stalked. 



5. P. WRIGHTIANA. 



5. Stipe and rachis atropurpureous, glaucous; pinnae ternately cleft or 

 divided or, if (rarely) pinnate, the 3 segments subequal, the apical 

 one sometimes stalked 6. P. ternifolia. 



1. Pellaea intermedia Mett. in Kuhn, Linnaea 36: 84. 1869. 



Sierra Ancha and Mazatzal Mountains (Gila County), Chiricahua 

 and Huachuca Mountains (Cochise County), near Patagonia (Santa 

 Cruz County), Baboquivari Mountains (Pima County), 3,500 to 7,000 



