318 BOTANY. 



of the pinnules; involucres continuous, formed of the membranaceous and 

 somewhat altered margin of the pinnule, at first reflexed along the two 

 sides and meeting at the midrib, at length opening out flat; rootstock short; 

 stalks stramineous, tufted ; fronds smooth, herbaceous, dimorphous ; sterile 

 ones on shorter stalks, tri — quadri-pinnatifid, with toothed or incised ovate or 

 obovate segments ; fertile ones long-stalked, less compound, with narrowly 

 elliptical or oblong-linear pod-like segments. — Allosorus, Bernhardi, in part. 

 The generic name was proposed in 1823 by Robert Brown, in Dr. Rich- 

 ardson's Appendix to Franklin's first journey, for our species, and with it he 

 associated the European Pteris crispa, Linn. Allosorus of Bernhardi is a 

 much older name, but the character assigned to it was exceedingly vague, 

 and the species referred to it, if by Bernhardi's expression " alle Adianta 

 spuria Sw." we are to understand the species of Pteris which Swartz placed 

 in his section Adiantoideai, are now scattered among half a dozen diverse 

 genera. Presl's Allosorus is likewise worthless, being a most heterogeneous 

 assemblage of unlike species. Since the true object of scientific nomen- 

 clature in botany is to clearly set forth natural affinities and distinctions, 

 and not, as some would have it, to perpetuate antiquated obscurities, I am 

 quite content to follow the great masters Robert Brown and Sir W. J. 

 Hooker in using the name Gryptoyramme, though the name Allosorus may 

 perhaps be kept, as by Mr. Baker, for a section of Pellcea. 



Cryptog-raiiiitie acrostichoides, E. Brown. — Or. crispa, forma Ameri- 

 cana, Hook. Sp. Pil. ii, p. 130. Allosorus acrostichoides, Sprengel, Gray's Manual. 



Usually iu dense tufts among rocks, often at high elevations. Isle Royale, Lake Superior, and 

 generally in the Eocky Mountains and the Sierra from Colorado and California northward to 5G° or 60° 

 north latitude (Dr. Richardson), and iu the Aleutian Islands, where it has a more condensed habit 

 (Allosorus foveolatus, Ruprecht). The American plant is considered a form of the European C. crispa by 

 Sir W. J. Hooker and by Dr. Milde, and one occasionally sees specimens which would seem so inter- 

 mediate iu charater as to justify this disposition, but the American plant is decidedly more rigid and 

 subcoriaceous than the other, has less compound fronds, less incised sterile segments, and lougcr and 

 more linear fertile ones. Iu C. crispa, the sporangia occupy only the upper portion of the fertile veins, 

 and in C. acrostichoides they descend nearly or quite to the midrib. Curiously enough, Dr. Milde makes 

 Pellcea gracilis also a form of his Allosorus crispus. 



VI. PELL2EA. Link. 

 $ 1. CHBILOPLECTON. Fee, Baker. 



" Texture herbaceous or subcoriaceous, and veins clearly visible, the invo- 

 lucre broad, and in most of the species rolled over the sorus till full maturity." 



