10 44 POLYPODIACEAE 



natp dandular pinnae broadest at base, deeply pinnatifid, noticeably short- 

 lairy below on the midribs or both midribs and midveins; veins simple or forked; 

 sori submarginal; indusia toothed. Dryopteris Oreopteris (Ehrh.) Maxon. Poly- 

 podium montanum Vogler. Alaska; Eu. Represented in our range by the variety 

 T Oreopteris hesperia Slosson, which differs chiefly in having the stipe and rachis 

 conspicuously powdered with small light brown scales, a few occurring also on 

 the midribs of the pinnae beneath, the fronds otherwise glabrous or occasionally 

 with only a few scattered microscopic hairs on or near the rachis or midribs, and 

 (?) the fronds smaUer. Near streams: B.C. Wash. Alaska. Mont.Subalp. 



3. T. Dryopteris (L.) Slosson. Rhizome slender, creeping; fronds scattered, 

 8-69 cm. long; blades broadly triangular; the three primary divisions stalked, 

 1-2 pinnate' segments oblong, obtuse, entire or toothed; rachis not winged; sori 

 submarginal. OAK FERN. Wood places: Greenl. Newf Va. Minn. (Black 

 Hills) S.D. Mont. Ida. Ore. Alaska; Colo., Ariz., and Eu. 



4. T. Robertiana (Hoffm.) Slosson. Rhizome slender, creeping; fronds 

 scattered, 13-62 cm. long, somewhat rigid; blaaes triangular-ovate, the three 

 primary divisions stalked, the lateral smaUer in proportion than in the preceding 

 species; sori submarginal. Woods: Alaska Yukon Terr. Que. la. Minn. 

 (?) Ida.;Eu. 



7. DRYOPTERIS Adans. SHIELD FERN, MALE FERN. 



Ferns with stipes not articulated to the rhizomes and mostly bipinnate to de- 

 compound fronds. Midribs and midveins of the pinnae's subdivisions attached 

 at a very acute angle. Veins pinnate, free, the veinlets usually forked. Sori 

 borne on the veins, round, usually indusiate. Indusia reniform or occasionally 

 resembling that in Filix. Fronds furnished with scales, at least on the stipes 

 and rachises, often glandular, without true hairs consisting of a single cell or row 

 of cells. Scales thin, entire or fimbriate, always consisting of 2 or more rows of 

 cells, which are mostly long and narrow, with flexuose walls. [Dryopteris, sub- 

 genus Eudryopteris C. Chr.] 



Indusia comparatively large, not dot-like. 

 Sori not close to the margin. 



Rachis usually conspicuously chaffy; fronds 4.5-40 cm. long. 1. D. fragrans. 

 Rachis naked or not noticeably chaffy; fronds 16-110 cm. long. 

 Pinnae triangular-oblong, or the lowest nearly triangular-ovate. 



2. D. cristata. 



Pinnae linear-lanceolate from a somewhat broader base. 4. D. Filix-rtias. 

 Sori close to the margin. 3. D. marginalis. 



Indusia minute, dot-like; blades bipinnatifld to tripinnate. 



Pinnules decurrent on the narrowly- winged midribs; indusia glabrous. 



5. D. spinulosa. 

 Larger pinnules not decurrent. 



Indusia, and frond when young, conspicuously glandular. 6. D. intermedia. 



Indusia glabrous or with only a few glands. 7. D. dilatata. 



1. D. fragrans (L.) Schott. Fronds borne in a crown, 4.5-40 cm. long, 

 aromatic; stipe and rachis chaffy with bright brown scales; blades lanceolate to 

 narrowly oblanceolate, somewhat narrowed toward base, nearly or quite bipin- 

 nate; pinnae oblong-lanceolate to deltoid-lanceolate; segments oblong, obtuse, 

 adnate-decurrent, subentire to deeply incised; indusia very large, ragged and some- 

 what glandular at margin. Onrocks: Alaska Ellesmereland Me. Minn. ; Russia. 



2. D. cristata (L.) A. Gray. Fronds crowded at apex of a short stout creep- 

 ing rhizome, the fertile erect, 2.5-10 dm. long, 7-15 cm. broad, much overtopping 

 the sterile; scales of stipe and rhizome pale brown, one-colored; blades linear or 

 lanceolate, bipinnatifid; segments rather broad, oblong or triangular-oblong, 

 obtuse, finely, usually sharply, serrate or obscurely or more deeply cut into ser- 

 rate lobes; sori about medial; indusia smooth. Swampy places and roadsides: 



Mack." n Ida. Man. Va. Newf .; Neb.; Eu. Submont.Subalp. 



3. D. marginalis (L.) A. Gray. Rhizome with golden brown scales; fronds 

 in a crown, 1.2-10 dm. long; blades evergreen, coriaceous, ovate-oblong or 

 ovate-lanceolate, usually bipinnate or nearly so; lower pinnae unequally deltoid- 



