go Our Native Ferns. 



XXFronds larger, mostly 2° — ^° high. 



A. Fronds bipinnatifid or nearly twice pinnate; indusia large 

 thinnish and flat. 



9. A. Floridanum,* D. C. Eaton. Stipes 6' — 10' long, spar- 

 ingly clothed with ovate scales ; fronds 18' — 20' long, 5' — 8' broad, 

 lanceolate ; fertile pinnse confined to the upper half of the frond, 

 narrowly lanceolate, cut down to the narrowly winged secondary 

 rachises into oblong, distinct pinnules ; the sterile pinnse broader, 

 shorter and sub-deltoid below, less deeply cut. {A. cristatum, var. 

 Floridanum, Hook. Fla. to La. VI. 



10. A. cristatum, Swz. Fronds linear-oblong or lanceolate in 

 outline, 1° — 2° long ; pinnse short, 2'— 3' long, triangular-oblong or 

 the lowest nearly triangular, deeply pinnatifid ; segments, 6 — lo 

 pairs, finely serrate or cut-toothed ; sori as near the midvein as 

 the margin ; indusium smooth, naked. Northern U. S. III. 



Var. Clintonianum,* D. C. Eaton. Fronds much larger, 2]4° 

 — 4° long ; pinnas oblong-lanceolate, broadest at base, 4' — 6' long, 

 if — 2' broad, deeply pinnatifid ; segments 8 — 16 pairs, crowded or 

 distant, linear-oblong, obscurely serrate ; veins pinnately forking 

 bearing the sori near the midvein. N. Eng., N. Y. and west- 

 ward. -III. 



11. A. Goldianum,* Hook. Fronds broadly ovate, 2° — 4° 

 long ; pinucB 6' — 9' long, broadest in the middle, pinnately parted ; 

 the segments, about 20 pairs, oblong-linear, sub-falcate, serrate 

 with appressed teeth ; veins bearing the sori very near the mid- 

 vein ; indusia very large, orbicular with a narrow sinus. N. Eng. 

 to Ky. and northward. III. 



B. Fronds mostly bipinnate; indusia convex, without marginal 

 glands. 



12. A. filix-mas, Swz. (Male-fern). Rhizoma short, stout ; 

 fronds in a crown, 1° — 3° high, broadly oblong-lanceolate, 

 slightly narrowed toward the base, bipinnatifid or bipinnate ; pin- 

 nules oblong, smooth, polished beneath, the larger ones pinnately 

 incised ; sOri large near the midvein commonly on the lower half 

 or two-thirds of the segment ; indusia firm, smooth ; rachis more 

 or less chaffy. Canada, L!''Superior to Col., Ore. and north- 

 ward. II. 



13. A. marginale,* Swz. Fronds smooth, nearly coriaceous 

 in texture, 6'— 2° long, ovate-oblong; pinnse lanceolate, broadest 

 just above the base ; pinnules oblong or oblong-falcate, entire or 

 crenately toothed ; sori close to the margin. Northern U. S. III. 



