138 PELLiEA. 



*** Fronds bi-tripinnate. 



9. V. gracilis ; caudex 4-6 inches high very slender fili- 

 form slightly scaly, fronds thin-membranaceous pale-green 

 bipinnate, sterile pinnules obovate or subrhomboidal sinuato- 

 lobate, fertile ones lanceolate ol)tuse crenate all more or less 

 petiolate, terminal ones elongated, veins remote simple or 

 forked, sori subrotund, involucres broad continuous very 

 thin membranaceous whitish subconvex but close-jiressed, 

 stipes very slender dark-brown glossy, superior rachises 

 winged, (Tab. CXXXIII. B.) — Allosorus gracilis, Pr., Gray, 

 Man. of the Bot. of North. U. St. p. 264. ed. 2. p. 591. t. 9 

 {excellent). Pteris gracilis, Mich. Fl. ii. p. 262 {not Fee). 

 Cheilanthes gracilis, Kaulf. Enum. Fil. p. 209. 



Hab. N. America; Canada (near Malhaye), Michaux ; Goldie in Herb. Nostr. 

 Shaded calcareous rocks, Vermont to Wisconsin, rare, Dr. Asa Gray. Dells of 

 the Wisconsin river, J. A. Lapham, Esq. Near New York, Dr. Knieskem; 

 VemuXAn, Dr. Sartvcll in Herb. Nostr. Northern India; Champwa, Kumaon, 

 elev. 10,000 feet, Messrs. Strachey and ]]'interbottom in Herb. Noslr. Balti, 

 N. W. Tibet, elev. 9000 feet ; temperate regions. Dr. T. Thomson.— The rarity 

 of this pretty and very delicate Fern, the difficulty of obtaining perfect speci- 

 mens, and the general resemblance of the fronds to that of some of the states 

 of Cryptogramme cri.spa, together witli my detecting specimens identical with 

 them among Dr. Thomson's and Messrs. Strachey and \A'interbottom's plants, 

 gathered by them as Cryptogramme crispa, induced me for a long time to refer 

 them to a form of that species ; nor did the excellent figure recently published of 

 Allosorus gracilis, in Dr. Asa Gray's second edition of his ' Manual of the Botany 

 of the Northern United States,' sufficiently convince me of my error. Upon lay- 

 ing my doubts before Dr. Gray, however, he most kindly sent me a beautiful 

 suite of specimens from Mr. Sullivant (gathered by Dr. Sartwell) with the ex- 

 pression of regret that they are destitute of " root-stock, which is never collected, 

 but it has a very small and filiform one, — not the thick rhizome of Allosorus 

 crispus ; nor do the fronds grow ia tufts, as in that species, but scattered, so that 

 the various shapes of frond may be found in the same patch (if the sparse assem- 

 blage may be so called) ; they are not clustered in one root." Thus, although 

 the barren and fertile pinnje differ in form, it is not that marked ditference that 

 is found in Cryptogramme, as seen in one and the same tuft. 



Thanks to these specimens, and others from Mr. Lapham, and to Dr. Gray's 

 remarks, I am satisfied the P. gracilis is a very distinct plant, that it is rather a 

 Pellcea than a Cryptogramme, and happily I find the slender filiform caudex, 

 alluded to by Dr. Gray, among Messrs. Strachey and Winterbottom's specimens. 

 This then is one of the characteristics of P. gracilis. The fronds are moreover 

 less comi)ound than in Cryptogramme ; the pinnules are fewer and more remote 

 upon each pinna; the texture is much more thin and delicate, more pellucid; 

 the involucre more uniformly tliin and membranaceous, all of the same texture, 

 and it is more closely appressed to the frond, never rolled back ; the sori are 

 shorter, rarely extended beyond the edge of the involucre, never covering the 

 whole i)ack of the pinnule ; the stipes is more slender, not stramineous, but deep 

 brown (badius) and glossy, scarcely ebeneous. 



10. p. airo-purpurea, Link; glabrous or with the rachis 



