348 FILICES. Cy.ilojderis. 



14. CYSTOPTERIS, Beinhanli. 

 Sori ratlicr small, roinul, placed on the back of tlio free veins, covered when ynung 

 by a very delicate roundish or ovate convex indusium lixcd across the veinlet just 

 below the sporanj,'ia, and usually turned back by the latter as they ripen. Delicate 

 ferns with small fronds. 



Of the five known species one {C. bulhifcra) is peculiar to Eastern North America, and two to 

 Europe and Western Asia. The other two occur in both iicinisplieres. 



1. C. fragilis, ISernhardi. Ivootstock elongated, creeping, chafly toward the 

 apex : stalks clustered, fragile, a few inches to a foot long : fronds broadly lanceo- 

 late, thin-membranaceous, smooth, usually bipinnate ; pinnae oblong-ovate or some- 

 what deltoid, pointed ; \nnnu\es decurrent on the winged secondary rhachis, ovate 

 or ovate-oblong, obtuse, toothed or variously incised with toothed lobules ; veiulets 

 mostly extending to the points of the teeth : sori small ; indusium roundish, entire 

 or toothed, often hidden by the ripened sporangia. — Torr. Fl. N. York, ii. 501 ; 

 Williamson, Fern Etchings, t. 4G ; Eaton, Ferns of N. Amer. ii. 49, t. 53, 



Common in rocky phaces. The lange of this fern is from witliin the Arctic Cii( le to Chili in 

 the west, and to South Africa and Tasmania in the cast. 



C. MONTANA, with small deltoid deliiatcly tripinnate fronds and a very slender and creeping 

 rootstock, has been found in the Kocky Jlountaiiis of IJritisii Anu'rica, and may possibly occur in 

 the northern part of the Sierra Nevada. 



15. WOODSIA, 1!. Brown. 

 Sori round, borne on the back of the free veins : indusium very delicate, attached 

 to the receptacle beneath the sporangia and at first partly or wholly enclosing them, 

 divided sometimes almost to the centre into irregular lobes or into a delicate fringe. 

 Small tufted ferns, growing on exposed rocks. 



This genus, consisting of a dozen or fifteen species, varies a good deal in the form of the indu- 

 sium, which is sometimes shaped at first like a bowl and then breaks into irregular segments, or 

 it is composed of several lobes folded together like an ohlfashioned wallet, or it is reduced to a 

 minute saucer-like scale beneath the sjiorangia, having the edge fringed with longer or shorter 

 cilia. Robert Brown's three original species, IT. I/vcnsis, hypcrborca and (fhibeUti, all occur in 

 Canada and the Northeastern States, and /F. ubiusa, Torrey, is common from the Atlantic to 

 Arkansas, and perhaiis Colorado. 



1. "W". SCOpulina, Eaton. Plant growing in dense tufts : stalks 2 to 4 inches 

 high, brownisli-stramineous, puberulent like the rhachis and the lower surface of the 

 frond with minute jointed hairs and stalked glands : fronds 4 to 8 inches long, oblong- 

 lanceolate, pinnate; pinna3 numerous, 8 to 15 lines long, oblong-ovate, subacute, 

 deeply pituiatilid into 5 to 8 pairs of short ovate or oblong obtuse crenulate or 

 toothed lobes : sori submarginal ; indusium very delicate, deeply cleft into narrow 

 segments which terminate in short hairs composed of irregular cylindrical cells. — 

 Canad. Nat. ii. 91, and Ferns of N. Amer. ii. 193, t. 71. 



From Mono Pass northward to Oregon and eastward to Colorado. This and the next have not 

 the obscure articulation in the stalk which is seen in the three species named by Robert Brown. 



2. W. Oregana, Eat(m. Habit and stature of the last, but the fronds almost 

 or quite smooth, the sterile ones shorter than the fertile ; teeth of the lobes often 

 reHexed and covering the submarginal sori : indusium very miimte, divided almost 

 to the centre into a few moniliform hairs. — Canad. Nat. ii. 90, and Ferns of N. 

 Amer. ii. 185, t. 71 ; (>ray's Manual, 5 ed. GG9 ; Williamson, Fern Etchings, t. 51. 



In masses around lava-rocks on high plateaus along Pitt River, Lcmmun. Oiegon to Lake 

 Superior, Colorado and Arizona. The glabrous fronds and rudimentary involucre distinguish it 

 from the last. 



