444 FILICES. (TRUE FERNS.) 



Var. incisum, Mett. Differs from the type in the rhachis with scanty 

 chaff ; the pinnules or segments rather distant, lanceolate, tapering to a sub- 

 acute point, and incised on the margin with serrated lobules. Eaton, Ferns 

 N. Am. i. 312. 



A. SPINULOSUM, Swartz, a very widely distributed and variable species, 

 is probably to be found within our range to the north and east. It has fronds 

 1 to 3 feet long, ovate to ovate-oblong, fully twice pinnate and but little nar- 

 rowed at base; pinnae short-stalked, the lowest ones triangular-lanceolate, 

 upper ones gradually narrower ; pinnules oblong, pinnate or pinnately incised 

 with spinulose-serrate lobes : indusium either smooth or glandular. 



# # Indusium orbicular and entire, fixed by the depressed centre to the middle of 



the sorus : pinnae, and pinnules often auricled on the upper side of the base. 

 2. A. Lonchitis, Swartz. Fronds simply pinnate, 6 to 18 inches long 

 (stalks only 1 to 3 inches), linear-lanceolate ; pinnae broadly lanceolate, falcr.te, 

 sharply spinulose-serrate, tbe lower ones symmetrically triangular and shorter, 

 the upper ones strongly auricled. In the Wahsatch Mountains, Utah, Mon- 

 tana, northward to British Columbia, and eastward to the Great Lakes. 



11. CYSTOPTERIS, Bernhardi. 



Tufted ferns, with slender and delicate twice or thrice pinnate fronds, and 

 cut-toothed lobes. 



1. C. fragilis, Bernh. Fronds 6 to 12 inches long, broadly lanceolate, 

 usually bipinnate ; pinnae oblong-ovate, pointed ; pinnules ovate or oblong, 

 variously toothed or incised. Throughout North America. Usually in crev- 

 ices of shaded rocks and among stones. 



12. WOOD SI A, R. Brown. 



Small tufted ferns growing on exposed rocks. Ours have the stalks not 

 articulated, and the fronds glandular-pubescent or smooth, not chaffy. 



1. "W. scopulina, Eaton. Fronds 4 to 8 inches long, puberulent beneath 

 with minute jointed hairs and stalked glands, oblong-ovate, pinnate with deeply 

 pinnatifid pinnae, the lobes oblong-ovate and crenulate : indusia deeplij clrft 

 into narrow segments terminating in jointed hairs. From Colorado westward to 

 California and Oregon, and eastward to Dakota and Minnesota. In dense 

 masses on rocks and in crevices. 



2. W. Oregana, Eaton. Very similar, but with smooth fronds, the fertile 

 taller than the sterile : the indusium reduced to a few moniliform hairs. From 

 Arizona and Colorado to British Columbia and Lake Superior. Habits like 

 the last. 



