Aspidium. 89 



4. A. Oreopteris, Swz. Rhizoma short, erect or decumbent, 

 scaly ; stipes short, tufted, scaly below ; fronds \\° — 2° long, firm 

 membranous, broadly lanceolate, gradually tapering and atten- 

 uated below, glandular ; pinnae 2' — 3' long, sessile from a broad 

 base, lanceolate-acuminate, deeply pinnatifid, gradually shorter to 

 the lowest which are more distant, deltoid and less than i' long ; 

 segments flat, nearly entire, oblong ; sori quite marginal ; indusia 

 delicate membranous, more or less toothed at the margin. Cal.? 

 Unalaska. IV. 



W Lower pinna little smaller than those above. 



5. A. Thelypteris, Swz. (Marsh-fern). Rhizoma slender; 

 fronds 1° — 2° long, 4' — 6' broad, lanceolate, pinnae mostly horizon- 

 tal, linear-lanceolate ; segments oblong, entire, obtuse or appear- 

 ing acute in fruit from the strongly revolute margins ; veins mostly 

 forked, bearing the sori near their middle ; indusium minute, 

 smooth and naked. Northern U. S. to Fla. III. 



6. A. patens, Swz. Rhizoma rather stout bearing several 

 fronds at the growing end ; fronds 2° — 3° long, 4' — 10' broad, 

 ovate-oblong, softly pubescent beneath ; pinnae closely placed, 

 linear-acuminate, lowest pair somewhat deflexed, all cut three- 

 fourths of the way to the midrib ; segments numerous, acutish, 

 basal ones longest ; veinlets evident, lowest ones of adjoining seg- 

 ments often uniting ; sori near the margin, indusia very pubescent. 

 Fla., S. C, Tex., Cal. VI. 



** Texture firmer or sub-coriaceous, veins forking freely. 

 \ Fronds pinnate ; pinnce cut into spreading triangular lobes; 

 sori confluent. 



7. A. unitum, R. Br., var. glabrum, Mett. Stipes 1° — 1^° 



long, brownish, naked ; fronds x%,° or more long, 5' — 8' broad ; 

 pinnae narrow cut from one-third to half-way down into sharp 

 pointed lobes; lower pinnae not reduced; veins pinnate in the 

 broad lobes with 6 — 8 veinlets on each side, the lower ones of con- 

 tiguous groups united ; sori near the ends of the veins principally 

 in the lobes. Fla. VI. 



\\ Fronds bipinnatifid or bipinnate ; indusia rather large; seg- 

 ments not spinulose. 



XFronds small, narrowly lanceolate. 



8. A. fragrans, Swz. Fronds 4'— 12' high, glandular and aro- 

 matic ; pinnae linear-oblong, pinnately parted : segments toothed 

 or nearly entire, nearly covered beneath with the very large thin 

 imbricated indusia, which are orbicular with a narrow sinus, the 

 margin ragged and sparingly glanduliferous. N. New England to 

 Wis. and northward. II. 



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