124 
BEAUTIFUL FERNS. 
Allosorus gracilis, Presl. Tent. Pterid., p. 153. — Torrey, FI. New 
York, ii., p. 486. — Gray, Manual, ed. i., p. 624; ed. ii., p. 591, 
t. ix. — Parry, in Owen’s Geol. Surv. of Wisconsin, etc., p. 
.621. — Mettenius, Fil. Hort. Lips., p. 44. 
Cheilanthes gracilis, Kaulfuss, Enum. Fil., p. 209. 
Pteris Stelleri, Gmelin, “Nov. Com. Petrop., xii., p. 519, t. 12, f. i.” 
Allosorus Stelleri, Ruprecht, Distr. Crypt. Vase, in Imp. Ross., p. 
47. — Ledebour, FI. Ross., iv., p. 526. — Moore, Ind. Fil., p. 
46. — Lawson, in Canad. Naturalist, i., p. 272. 
Allosorus minutus & Pteris minuta, Turczaninow, fide Moore'. 
Hab. — Crevices of damp and shaded calcareous rocks, especially in 
deep glens; Labrador, Butler, to British Columbia, and southward to 
Iowa, Parry, Wisconsin and Pennsylvania. Also in Colorado, near 
Breckinridge City, Brandegee. Siberia, Tibet and the Himalayas. It 
is found in Sunderland, Massachusetts; at Trenton Falls, Chittenango 
Falls, and other deep glens in Central New York; in Lycoming and 
Sullivan Counties, Pennsylvania, and in other similar places in Vermont, 
Michigan, etc., but is by no means a common plant. 
Description: — This is the most delicate of all the 
Pellceas, and has fronds a good deal like those of Crypto- 
gramme acrostichoides, but tenderer, and with sub-marginal 
fructification. The root-stock is very slender, scarcely more 
than half a line in thickness, and sometimes two or three 
inches long. It is so hidden in the crevices of the rocks 
that it is seldom secured by collectors. The scales are mi- 
nute, appressed to the root-stock, and almost filmy in their 
delicacy. 
