POLYPODIACEAE (FERN FAMILY) 21 



brown, 8-20 cm. long: fronds 3-5 cm. long, ovate, closely tripinnate; the 

 ultimate segments linear, 6-12 mm. long, sessile; the sterile ones serrate. In 

 clefts of rocks; northwestern Wyoming to Oregon and California. 



4. Pellaea Wrightiana Hook. 1. c. 142, t. 115. Rootstock short, thick, 

 densely chaffy: stipes crowded, purplish-brown: fronds 1-2 dm. long, lanceolate 

 to triangular-ovate, bipinnate; pinnae longer than broad, having 3-13 oval or 

 oblong-oval pinnules; fertile ones with the margins rolled in to the midvein. 

 Exposed rocky places in canons; Colorado to Arizona and Texas. 



9. DRYOPTERIS Adans. SHIELD FERN 



Rather large coarse ferns; in ours the fronds bipinnate and subcoriaceous. 

 Indusia roundish-reniform with a narrow sinus, attached to the middle of the 

 sorus by a short central stalk. Veins free and the large sori borne near the mid- 

 vein. Aspidium in part. 



1. Dryopteris Filix-mas (L.) Schott. Gen. Fil. 1834. Fronds 3-8 dm. long, 

 broadly oblong-lanceolate, somewhat narrowed and twice pinnate towards the 

 base; pinnae lanceolate-acuminate from a broad base; pinnules or segments 

 oblong to ovate-lanceolate, obtuse or acute, toothed or incised, not glandular 

 but sometimes slightly chaffy beneath, the upper confluent: sori near the mid- 

 .vein, commonly only on the lower half of each segment: stalks more or less 

 chaffy with large scales. Aspidium Filix-mas. MALE FERN. Somewhat vari- 

 able; cosmopolitan, and not infrequent in our range. 



10. POLYSTICHUM Roth. HOLLY FERN 



Ferns with pinnate leaves and numerous large contiguous round sori; the 

 indusium orbicular and entire, fixed by the depressed center to the middle of 

 the sorus. Pinnae and pinnules often auricled on the upper side of the base. 

 Veins all free and the large sori borne near the margin of the leaf. Aspidium 

 in part. 



1. Polystichum Lonchitis (L.) Roth, Tent. Fl. Germ. 3: 71. 1800. Fronds 

 simple pinnate, 1-4 dm. long (stalks only 3-7 cm.), linear-lanceolate; pinnae 

 broadly lanceolate, falcate, sharply spinulose-serrate, the lower ones symmet- 

 rically triangular and shorter, the upper ones strongly auricled. Mountains 

 of Colorado, Utah, and Wyoming, north to Canada and east to the great lakes. 



11. FILIX Adans. 



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

 cut-toothed lobes. Indusium delicate, hood-like, or arched, attached by a 

 broad base on the inner side partly under the sorus, free at the other side and 

 early thrown back or withering away. V,eins free. Cystopteris. 



1. Filix fragilis (L.) Underw. Our Native Ferns 119. 1900. Fronds 

 1-3 dm. long, broadly lanceolate, usually bipinnate; pinnae oblong-ovate, 

 pointed; pinnules ovate or oblong, variously toothed or incised. Cystopteris 

 fragilis. BRITTLE FERN. Usually in shaded rock-crevices; throughout North 

 America. 



12. WOODSIA R. Br. 



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

 articulated to the rootstock, and the fronds are glandular-pubescent or 

 smooth, not chaffy. Indusium situated beneath the sorus and partly or wholly 

 inclosing it, soon dividing into irregular lobes or bursting into a delicate fringe 

 above. 



Fronds glandular-puberulent beneath . . . . . . .1. W. scopulina. 



Fronds smooth beneath ......... 2. W. oregana. 



