i8 



POLYPODIACEAE. 



VOL. I. 



Indusia flat, thin. 



Blades narrow, linear-oblong to lanceolate ; sori nearly medial. 5. D. cristata. 

 Blades broader, narrowly oblong, ovate or triangular ovate ; sori near midvein. 

 Apex attenuate ; pinnae broadest at base ; sori 3-7 pairs. 6. D. Clintoniana. 

 Apex short-acuminate, often abruptly so ; pinnae broadest above the base ; 



sori 6-10 pairs. 7. D. Goldiana. 



Indusia convex, firm. 



Sori near the margin. 8. D. marginal is. 



Sori near the midvein. 9. D. Filix-mas. 



Blades 2-pinnate to 3-pinnate ; segments spinulose or mucronate. 



Blades ovate-lanceolate, triangular, or broadly oblong, usually not narrowed below. 

 Indusia glabrous or nearly so ; pinnae usually somewhat oblique to the rachis, the 



lowest broadly and unequally ovate to triangular. 

 Pinnules flat, decurrent ; sori terminal on the veinlets ; scales pale brownish. 



10. D. spinulosa. 

 Pinnules concave, some not decurrent ; sori mostly subterminal ; scales dark brownish. 



n. D. dilatata. 

 Indusia glandular ; pinnae usually at right angles, the lowest unequally lanceolate to 



ovate-lanceolate. 12. D. intermedia. 



Blades elongate-lanceolate, usually narrowed below. 13. D. Boottii. 



Indusia wanting ( Phegopteris). 



Basal pinnae sessile or partially adnate : rachis more or less alate. 



Blades usually longer than broad; rachis and midveins freely chaffy; under surfaces pilose. 



14. D. Phegopteris. 



Blades usually broader than long; rachis and midveins scarcely scaly; under surfaces 

 slightly pubescent. 15. D. hexagonoptera. 



Basal pinnae long-stalked ; rachis not alate. 



Blades nearly horizontal, glabrous or nearly so, subternate, the basal pinnae approaching 



the terminal portion in size. j 6. D. Dryopteris. 



Blades suberect, copiously glandular, triangular-ovate, the basal pinnae considerably smaller 

 than the terminal portion. 17. D. Robertiana. 



i. Dryopteris noveboracensis (L.) A. Gray. 

 New York Fern. Fig. 37. 



Polypodium noveboracense L. Sp. PI. 1091. 1753. 

 Aspidium noveboracense Sw. Schrad. Journ. Bot. 



i8oo 2 : 38. 1801. 

 Dryopteris noveboracensis A. Gray, Man. 632. 1848. 



Rootstock slender, widely creeping. Stipes slen- 

 der, short; blades lanceolate, tapering both ways 

 from the middle, i-2 long, 4,' -7' wide, membra- 

 nous, once pinnate, the apex long-acuminate ; pinnae 

 ii'-3$' Jong, lanceolate, sessile, long-acuminate, 

 deeply pinnatifid, pilose along the midribs and veins, 

 especially beneath, ciliate, the lower (2-7) pairs 

 gradually shorter and deflexed, commonly distant, 

 the lowest auriculiform ; segments flat, oblong, ob- 

 tuse, the basal ones often enlarged; veins simple or 

 those of the basal lobes forked ; sori near the mar- 

 gin ; indusia small, delicate, glandular, withering. 



In moist woods and thickets, Newfoundland to On- 

 tario and Minnesota, south to Georgia, Alabama and 

 Arkansas. Ascends to 5000 ft. in Virginia. Sometimes 

 sweet-scented in drying. July-Sept. 



2. Dryopteris Thelypteris (L.) A. Gray. 

 Marsh Shield-fern. Fig. 38. 



Acrostic hum Thelypteris L. Sp. PI. 1071. 1753. 

 Aspidium Thelypteris Sw. Schrad. Journ. Bot. i8oo 2 : 40. 



1801. 

 Dryopteris Thelypteris A. Gray, Man. 630. 1848. 



Rootstock slender, creeping, blackish. Leaves long- 

 stipitate, the blades lanceolate or oblong-lanceolate, 

 scarcely narrowed at base, i-24 long, 4'-6' wide, 

 short-acuminate, membranous, once pinnate ; pinnae 

 ii'-3' long, linear-lanceolate, short-stalked or sessile, 

 horizontal or decurved, broadest at the base, short- 

 acuminate, pubescent or pilose beneath, deeply pinnat- 

 ifid ; segments oblong, obtuse or appearing acute from 

 the strongly revolute margins; veins regularly once or 

 twice forked ; sori nearly medial, crowded ; indusia 

 small, glabrous. 



In marshes and wet woods, rarely in dry soil, New 

 Brunswick to Manitoba, south to Florida, Louisiana and 

 Texas. Ascends to 2000 ft. in Vermont. Europe and 

 Asia. Summer. Wood-, Swamp-, Quill- or Marsh-Fern. 



