FILICES. 105 



with lower edge of pinnse. Huachuca Mountains, Arizona 

 (^Leiinnoti). 



\\ RacJiis green. 



8. A. viride Hiids. Stipes densely tufted, 2'— 4' lon.ii:, 

 naked, the lower part chestnut-brown ; fronds 2—6' long, ^ 

 broad, with 12—20 pinnse on each side, which are ovate or 

 rhomboidal in outline, the upper edge narrowed suddenly at 

 the base, the lower obliquely truncate, the outer part deeply 

 crenate ; rachis naked ; sori copious. Vermont, Canada, and 

 New Brunswick. 



9. A. dentatum L. Stipes tufted, 2—6' long, naked, 

 ebeneous below; fertile fronds 2'— 3' long, i' broad, with 6—8 

 pairs of stalked, oblong-rhomboidal pinnae, the lower side trun- 

 cate with a curve, the outer edge irregularly crenate ; sterile 

 fronds smaller on shorter stipes ; rachis naked ; sori copious in 

 parallel rows. Florida, South Carolina. 



ft Pi'nncE only 2 — 5, linear-cuneafe. 



10. A. septentrionale (L.) Hoffm. Stipes dense, tufted, 

 3' — 6' long, slender, naked, ebeneous toward the base ; fronds 

 irregularly forking, consisting of two to five narrowly linear 

 rather rigid segments, which are entire or more frequently cleft 

 at the end into a few long narrow teeth ; sori elongate, placed 

 near the margin, usually facing each other in pairs, commonly 

 only two or three to each segment. Ben Moore, New Mexico 

 {Bigehnu) ; Middle Mountains, Colorado, Arizona. 



ttt PinncB numerous, linear or linear-oblotig, acuie or acuim'nafe. 



11. A. ang-ustifolium Michx. Stipes 1° or irnre long, 

 brownish, slightly scaly below ; fronds 1^° — ?.° long, 4' — 6' 

 broad, lanceolate-oblong, flaccid ; pinnae 20—30 pairs, linear- 

 lanceolate, acuminate, entire or crenulate, those of the fertile 

 frond narrower; texture thinly herbaceous ; sori linear, 20 — 40 

 each side of the midvein. New England to Kentucky and Wis- 

 consin. 



12. A. firmum Kunze. Stipes 4' — 8' long, erect, grayish, 

 naked; fronds 6' — 12' long, 3' — 4' broad ; pinnae 12 — 20 pairs, 

 oblong-lanceolate, the point blunt ish, the margin inciso-cre- 

 nate, the upper one narrowed suddenly at the base, the lower 



