GENUS 17. 



FERN FAMILY. 



33 



2. P. densa. 



17. PELLAEA Link, Fil. Hort. Berol. 59. 1841. 



Rock-loving small or medium-sized ferns, with nearly uniform leaves, the blades 

 l-3-pinnate, smooth, the fertile divisions commonly narrower than the sterile. Sori roundish 

 or elongate, on the free veins, usually confluent in a submarginal line. Indusium formed by 

 the reflexed margins of the segments. [Greek, alluding to the dark-colored stipes.] 



About 50 to 60 species of wide geographic distribution. Besides the following several occur 

 in the western and southwestern United States. Type species : Pellaea atropurpurea (L.) Link. 

 Blades pinnate or 2-pinnate with large pinnules. i. P. alropurpurea. 



Blades small, 3-pinnate, the pinnules narrow. 



i. Pellaea atropurpurea (L.) Link. 

 Purple-stemmed Cliff-brake. Fig. 76. 



Pteris atropnrpurea L. Sp. PI. 1076. 1753- 



Pellaea atropurpurea Link, Fil. Hort. Berol. 59. 



1841. 



P. glabella Mett. ; Kuhn, Linnaea 36: 87. 1869. 



Rootstock short, densely clothed with long- 

 attenuate rusty scales. Stipes tufted, 2'-8' 

 long, dark purple, smooth, or, with the rachis, 

 more or less pubescent with hair-like chaff; 

 blades coriaceous, lanceolate, ovate-lanceolate 

 or deltoid-ovate, 4' -12' long, 2' -6' wide, simply 

 pinnate, or below 2-pinnate; pinnules and 

 upper pinnae i'-2 f long, glabrous, or sparsely 

 fibrillose below, 3" or less wide, short-stalked 

 or sessile; veins obscure. 



On rocks, preferring limestone, Ontario to 

 British Columbia and Mackenzie, Georgia, Mis- 

 sissippi, Texas and California. Reported from 

 northern Mexico. June-Sept. Clayton's Cliff- 

 brake, Rock- or Winter-brake, Indian's Dream. 



2. Pellea densa ( Brack.) Hook. Oregon 

 or Clayton's Cliff-brake. Fig. 77. 



Onychium densum Brack. Fil. U. S. Expl. Exp. 



120. 1854. 



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



Rootstocks slender, creeping, entangled, chaffy 

 with narrow blackish scales. Stipes numer- 

 ous, densely tufted, wiry, slender, light brown, 

 3'-o/ long; blades ovate or triangular-oblong, 

 i '-3' long, densely 3-pinnate, the segments 

 3"-6" long, linear, nearly sessile, acuminate or 

 mucronate, those of the fertile blades taper- 

 ing at each end, with narrowly recurved mar- 

 gins ; indusium distinctly scarious; segments 

 of the rarely sterile blades broader and serrate. 



Mt. Albert, Gaspe, Quebec and Grey county, 

 Ontario ; British Columbia to Montana, Wyoming 

 and California. Summer. Indian's Dream. 



18. CHEILANTHES Sw. Syn. Fil. 

 126. 1806. 



Small rock-loving ferns, mostly with pubescent, tomentose or scaly leaves, the blades 

 uniform, i-3-pinnate, the divisions often minute and bead-like. Sori terminal upon the 

 veins, marginal, roundish and distinct, or somewhat confluent, often obscured by the hairy 

 or scaly covering. Indusia formed of the revolute or reflexed usually modified margins of 

 the segments. [Greek, in allusion to the marginal sori.] 



About 100 or more species, of temperate and tropical regions. Besides the following numer- 

 ous other species occur in the southwestern and western United States and in Mexico, 

 species : Chcilanthes micropteris Sw. 



Blades nearly glabrous. i. C. alabamensis. 



Blades hirsute or tomentose. 



Blades hirsute and glandular; indusia discontinuous. 

 Blades tomentose; indusia mostly continuous. 



