PeUasa. FILICES. 339 



allied to Cheilanlhes, from which it differs in the continuous involucre, and in never having to- 

 mentose or scaly fronds. 



1. Fronds herbaceous or subcoriaceous ; veins clearly visible ; involucre broad, 

 and usually covering the sporangia till they are fully ripe. CHEILO- 

 PLECTOX, Hooker & Baker. 



1. P. Breweri, Eaton. Plant 4 to 8 inches high : rootstock short, stout, very 

 chaffy with narrow fulvous scales : stalks crowded, terete, fragile, brigl it-brown, 

 chaffy only at the base : fronds as long as the stalks, oblong, pinnate ; pinnae six to 

 twelve pairs, short-stalked, membranaceous, 6 to 9 lines long, mostly two-parted, the 

 upper lobe largest ; lobes and simple upper pinnae ovate or triangular-ovate, cuneato 

 and often subcordate at the base ; veins twice or thrice forked ; involucre delicate. 

 Proc, Amer. Acad. vi. 555, Bot. King Exp. 395, t. 40, fig. 17, and Ferns of N. 

 Arner. i. 331, t. 43. 



Clefts of exposed rocks in the higher canons of the Sierra Nevada, thence eastward to the 

 Wahsatch ; also in Colorado near the Rio Grande. Thinner in the texture of the frond than any 

 of the following, and related to P. gracilis of the East, and to the Mexican P. Secnuinni. The 

 stalks are excessively fragile. 



2. Fronds coriaceous or subcoriaceous ; veins not evident ; involucre conspicu- 

 ous. ALLOSORUS, Hooker & Baker. 



* Pinnules obtuse or emarginate. 



2. PC andromedsefolia, Fe'e. Eootstock slender, creeping, chaffy with nar- 

 row rusty scales : stalks scattered, erect, terete, smooth, brownish or reddish, chaffy 

 at the base, variable in length : fronds 4 to 24 inches long, ovate or ovate-oblong, 

 2 4-pinnate ; primary pinnae spreading, oftenest .opposite, ovate-lanceolate ; ulti- 

 mate pinnules glaucescent, subsessile, 2 to 4 lines long, broadly oval, slightly cordate 

 and emarginate, fertile ones with the edges rolled back to the midvein : involucre 

 herbaceous with a narrow whitish edge. Gen. Fil. 129 ; Hooker, Sp. FiL ii. 149 ; 

 Eaton, Ferns of N. Amer. i. 203, t. 27, fig. 1. Allosorus andromedcefolius, Kaulf. 

 in Kunze, Analect. Pteridogr. 18, t. 11. 



Rocks and hillsides, mostly in the Coast Ranges ; also in Chili. Plants with blood-red fronds 

 occur in the southern counties (var. rubens, Eaton in Torr. Bot. Bulletin, vi. 360). The color is 

 now believed to be occasioned by direct sunlight. 



* Pinnules acute or mucronate. 

 Fronds bipinnate only. 



3. P. Wrightiana, Hooker. Eootstock short, thick, nodose, densely chaffy 

 with narrow appressed dark-brown scales : stalks clustered, dark-purplish, polished, 

 very rigid, 4 to 10 inches long : fronds 4 to 10 inches long, lanceolate or triangular- 

 lanceolate in outline, bipinnate, pinnae subsessile, spreading ; pinnules coriaceous, 

 smooth, beneath glaucescent, at most about six pairs, crowded or remote ; those of 

 the sterile fronds roundish-oval, 3 to 5 lines long, two thirds as broad, rounded and 

 even subcordate at the base, the apex obtuse, but with a minute cartilaginous subu- 

 late point ; those of the fertile fronds rolled back to the midvein, often longer than 

 the sterile ones and curved upwards, similarly mucronate. Sp. Fil. ii. 142, t. 115, B; 

 Eaton, Ferns of N. Amer. ii. 5, t. 47, fig. 1 3. Also P. longimncronata, Hooker, 

 1. c. 143, t. 115 A. P. mucronata, Eaton in Bot. Mex. Bound. 233, in part. 



Growing in heavy compact masses from under a rock on Mount San Bernardino, at 7,000 feet 

 altitude ( IV. G. Wright, Lemmon) ; Arizona, New Mexico, and Bolivia (P. Wcddclliana, Fee). 

 The rootstocks are compacted in great masses, and though the resemblance to bipinnate forms 

 of P. Ornithopus is considerable, it seems best to keep the two ferns apart. 



4. P. brachyptera, Baker. Eootstock short, knotted, chaffy with narrow 

 rusty denticulate scales : stalks 6 to 8 inches long, erect, wiry, blackish and shining : 

 fronds nearly as long as the stalks, rigid, narrowly oblong-linear in outline, bipin- 



