268 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



2. Dryopteris dilatata (Hoffm.) Underw. Wood pern. Frequent in moist woods 

 and in alder thickets; sometimes about sphagnum bogs. Alaska to Calif., Mont., 

 N. C, and Greenl.; also in Eur. (Aspidium spinulosum dilatatum Hook.) — Leaves 

 loosely tufted, 25 to 90 cm. high, pale green, triangular-ovate to broadly oblong; 

 pinnules with short-pointed teeth. 



Usually associated with the lady fern and male fern. The plants are mostly 

 scattered, but in some localities they are abundant. 



3. Dryopteris cristata (L.) A. Gray. Crested shieldfern. Rare; under bushes 

 at edge of sphagnum bog, Johns Lake. Idaho to Nebr., Va., and Newf. {Aspidium 

 cristatum Swartz.) — Leaves densely tufted, 25 to 60 cm. long, the fertile ones much 

 longer than the sterile ones; scales of the leaf stalk pale brown; segments of the leaf 

 broad, oblong or triangular-oblong, obtuse, finely toothed. 



4. Dryopteris filix-mas (L.) Schott. Male fern. Frequent in moist woods; 

 sometimes on moist, open or brushy slopes, or even on rock slides; occasionally 

 found above timber line. B. C. to Oreg., N. Mex., S. Dak., Vt., and Newf.; southern 

 Calif.; also in Eur. (Aspidium filix-mas Swartz.) — Leaves tufted, deep green, rather 

 firm, 25 to 100 cm. long, broadly oblong-lanceolate; pinnules toothed, especially at 

 the apex. 



Usually associated with the lady fern; a fine, handsome plant, the fronds usually 

 stiffly erect. 



10. WOODSIA R. Br. Woodsia. 



Leaves densely tufted, often forming large clumps, rather stiff, erect, pinnate, the 

 pinnae deeply lobed and toothed. 



Leaves with flat jointed whitish hairs on the lower surface . . . 1. W. scopulina. 

 Leaves without jointed hairs 2. W. oregana. 



1. Woodsia scopulina D. C. Eaton. Frequent on cliffs and rock slides. Alaska to 

 Calif., N. Mex., and Nebr.; Que. and N. C. — Leaves 10 to 30 cm. long, lanceolate; 

 pinnae oblong-ovate. 



2. Woodsia oregana D. C. Eaton. East entrance, on rocky hills, Uvibach. B. C. to 

 Calif., Ariz., Sask., and Que.— Leaves 10 to 25 cm. long, lance-oblong; pinnae 

 triangular-oblong. 



11. FILIX Adans. 



1. Filix fragilis (L.) Gilib. Brittle fern. Frequent at nearly all altitudes, on 

 cliffs or mossy banks. Widely distributed in N. Amer. and in the Old World. 

 {Cystopteris fragilis Bernh.) — Leaves few, soft and lax, 10 to 30 cm. long, oblong- 

 lanceolate, 2 or 3 times pinnate; pinnae ovate or lanceolate, irregularly lobed or 

 toothed. 



One of the most widely distributed of all ferns. The leaf stalks are very brittle. 

 The brittle fern often grows with Woodsia, but it is easily recognized by the thin 

 leaves, which are often pendent. The leaves, too, do not endure dry weather like 

 those of Woodsia, but turn yellow and shrivel. 



3. EQTJISETACEAE. Horsetail Family. 



1. EQUISETUM L. Horsetail. 



Rushlike plants, simple or with whorled branches, with rootstocks, the stems 

 hollow, jointed, with toothed sheaths at the nodes; spores borne in a terminal cone 

 composed of shieldlike bracts. — The stems are roughened with a gritlike silex. They 

 were formerly much used for scouring, hence the name scouring-rush, which is some- 

 times applied to the plants. 



The following key to the species has been furnished by Dr. J. H. Schaffner. 



