1042 POLYPODIACEAE 



or triangular-ovate, pinnately parted or pinnate below; segments oblong, obtuse, 

 crenate-dentate or the lower pinnatifid with toothed lobes. "N.S." — N.H. — Ga. 

 — N.M.— Wis.; Ariz, and (?) "B.C." 



4. FILIX Adans. 



Ferns, with pinnately compound fronds of rather thin texture. Sori roundish, 

 indusiate, borne on the veins. Indusia dehcate, hood-hke or flattish, attached 

 at one side of and partly under the sorus, at first arched over it, finally thrown 

 back or withering. Veins free. [Cystopteris Bernh.] 



Blades of the fronds deltoid-lanceolate or broadly lanceolate, twice or thrice pinnate. 

 Blades elongate deltoid-lanceolate, 3-12 dm. long; basal pair of pinnae the largest. 



1. F. bulbifera. 

 Blades broadly lanceolate, 2^.5 dm. long; basal pair of pinnae usually shghtly short- 

 ened. 2. F. fragilis. 

 Blades of the fronds deltoid-ovate, three to four times pinnate. 3. F. montana. 



1. F. bulbifera (L.) Underw. Rhizome short; fronds clustered; blades 

 minutely more or less glandular beneath, especially on the rachises and midribs; 

 pinnae oblong-ovate to lanceolate-oblong, pinnate; pinnules unequally oblong- 

 ovate, obtuse, variously inci.sed to deeply pinnatifid, more or less adnate or free ; 

 rachis and pinnae commonly bulbiferous beneath, the bulblets producing new 

 plants after falUng to the ground; indusia short, convex, truncate. C. bulbifera 

 (L.) Bernh. Damp places, especially about rocks: "Newf." — N.S. — "Man." — 

 Wis.- — -Ark. — Ga.; Utah — Ariz. Boreal — Austr. — Son. 



2. F. fragilis (L.) Gilib. Rhizome creeping; fronds clustered or slightly 

 scattered, glabrous; stipe and primary rachis slender, brittle, stramineous or 

 brownish below; secondary rachises usually winged; pinnae deltoid-lanceolate or 

 deltoid-ovate; segments decurrent, variable, roundish-oval or ovate or rhomboid- 

 ovate or ovate-lanceolate, dentate, with short obtuse teeth or deeply toothed or 

 cleft, with narrower teeth, or cleft or sometimes pinnatifid, with toothed segments ; 

 indusia dehcate, convex, roundish or commonly pointed, often toothed or lacini- 

 ate at apex. Cystopteris fragilis (L.) Bernh. Rocky places: Greenl. — Ga. — 

 Okla. — Cahf. — Alaska; trop. Am., and the Old World. Plain — Alp. 



3. F. montana (Lam.) Underw. Rhizome slender, creeping; fronds scat- 

 tered, 12-45 cm. long; stipes slender; blades often subternate; basal pair of pin- 

 nae much the largest, unequally deltoid-ovate; pinnules deeply divided; segments 

 oblong, deeply toothed or divided; indusia convex, ovate, soon thrown back or 

 •evanescent. Lab. — Que. — Ont.; Colo.; B.C. — Alaska; Eurasia. Mcnii. — Sub- 

 alp. 



5. POLYSTICHUM Roth. Holly Fern, Christmas Fern. 



Ferns of mostly rigid habit, with firm-textured pinnate to pinnately decom- 

 pound fronds usually with sharply toothed or spinulose margins. Sori roimd, 

 indusiate, borne on the veins. Indusium peltate. Veins free. 



Blades normally simply pinnate; piimae auricled or the upper side at base, obUquely 

 truncate at the lower. 

 Fronds very short-stalked; pinnae broadly lanceolate, falcate, on the lower triangular. 



1. P. lonchitis. 

 Fronds rarely very short-stalked; pinnae horizontal, slightly falcate, lanceolate or 

 linear, afuminate. 2. P. munilum. 



Blades ncjnnallv more compound. 



Blades jwiiliferous below the ape.x. 3. P. Andersoni. 



Blades not proliferous. 



Pinnae serrate in the distal part, pinnately lobed at base. 4. P. scnpulinum. 



Pinnae pinnately divided almost throughout the blade, commonly fully bipinnate. 



5. /'. Braunii. 



1. P. Lonchitis (L.) Roth. Fronds growing in a crown, 8-22 cm. long; 

 stii)es and rachises chaffy with light brown scales; blades linear-lanceolate, 

 gradually tapering toward base; pinnae 1-4.5 cm. long, densely spinulose-toothed, 

 the teeth mostly spreading; sori medial or supramedial. Woods: Greenl. — N.S. — 

 "Wis." — Alta. — Colo.— Calif. — Alaska. Boreal. 



2. P. munitum (Kaulf.j Presl. Frondsgrowinginacrown, 22-152 cm. long; 

 stipes densely chaffy at base, less so above; rachises chaffy; scales bright reddish 



