Camptosorus, Phegopteris. 87 



the outer ones inclined to approximate in pairs, or to become con- 

 fluent at their ends, thus forming crooked lines. 



I. C. rhizophyllus,* Link. Fronds evergreen, tufted, spread- 

 ing or procumbent, 4' — 9' long, lanceolate from an auricled, heart- 

 shaped or^ often hastate base, tapering above into a slender pro- 

 longation which often roots at the apex. N. Eng. to Wis. and 

 southward. III. 



XVIII. PHEGOPTERIS, Fee. Beech-fern. 

 Sori small, round, naked, borne on the back of the veins below 

 the apex. Stipe continuous with the rhizoma. Veins free in our 

 species. 



'''Fronds triangular, bipinnatifid ; pinnce sessile, adnate to a 

 winged rachis. 



1. P. polypodioides, Fee. Stipes 6'— 9' long ; fronds 4' — 9' 

 long, 4' — 6' broad, hairy on the veins especially beneath ; pinnae 

 linear-lanceolate, the lowest pair deflexed, and standing forward ; 

 segments oblong, obtuse, entire, the basal ones decurrent and 

 adnate to the main rachis ; sori near the margin. N. Eng. to Va. 

 and westward. 11. 



2. P. hexagonoptera,* Fee. Stipes 8' — 18' long, stramineous, 

 naked; fronds 7'^I2' long, nearly as broad, slightly pubescent, 

 and often finely glandular beneath ; upper pinnae oblong, obtuse, 

 toothed or entire, the very large lowest pinnae elongated and 

 pinnately lobed ; sori near the margin or some between the sinus 

 and the midrib. Canada to 111., Ky., Miss, and Fla. III. 



**Fronds oblong-lanceolate, tripinnatifid ; rachis wingless. 



3. P. alpestris, Mett. Rhizoma short, thick, erect or oblique ; 

 stipes 4' — 10' long, with a few brown spreading scales near the 

 base ; fronds i" — 2° long, pinnae deltoid-lanceolate, the lower ones 

 distant and decreasing moderately; pinnules oblong-lanceolate, 

 incised and toothed ; sori small, rounded, sub-marginal. Cal. and 

 northward. IV. 



***Fronds ternate, the three divisions petioled ; rachis wingless. 



4. P. Dryopteris, Fee. (Oak-fern). Rhizoma slender, creep- 

 ing; fronds broadly triangular. 4' -8' wide; the three primary 

 divisions i — 2 pinnate ; segments oblong obtuse, entire or toothed ; 

 sori near the margin. Northeastern U. S. to Ore. II. 



5. P. calcarea, Fee. Stipes 6' — 10' long, stramineous when 

 dry, glandular ; fronds 6'— 8' long, 5' — 7' wide, deltoid-ovate in 

 outline , bipinnate, lowest pair of pinnse far the largest, pinnatifid 



