74 Our Na/ive Ferns. 



** Fronds dichotomously forked, with numerous pinncs spring- 

 ing from the upper side of the two branches. 



5. A. pedatum, L. Stipes 9' — 15' long, dark chestnut-brown, 

 glabrous; fronds nearly circular in outline; central pinnae 6' — 9' 

 long, 1'— 2' broad; pinnules triangular-oblong, short-stalked; sori 

 roundish or transversely oblong. N. C. to Cal. and northward. III. 



VII. PTERIS, L. Brake. 

 Sori marginal, linear, continuous, occupying a slender filiform 

 receptacle which connects the tips of the free veins. Indusium 

 membranous, formed of the reflexed margin of the frond. 



§1. EUPTERIS. Veins free, stipes tufted, indusium single. 

 * Lower pinner linear, undivided. 



1. P. longifolia, L. Stipes 6' — 12' long, clothed more or less 

 below with pale brown scales; fronds 1° — 2° long, 4' — 9' broad, 

 oblong-lanceolate ; pinnae sessile, 2"— 5" broad, linear, enfire ; 

 veins close and fine, usually once branched ; indusium yellowish- 

 brown. Fla. VI. 



** Lower pinncE forked or slightly pinnate below, 



2. P. Cretica, L. Stipes 6' — 12' long, erect, stramineous or 

 pale-brown; fronds 6'— 12' long, 4' — 8' broad, lateral pinnae usu- 

 ally in 2 — 6 opposite sessile pairs, the sterile ones considerably the 

 broadest and spinulose-serrate, the lower pairs often cleft nearly 

 to the base, into two or three linear pinnules ; veins fine, parallel, 

 simple or once forked ; indusium pale. Fla. VI. 



3. P. serrulata, Linn. f. Stipes 6' — 9' long, naked, pale or 

 brownish ; fronds 9' — 18' long, 6' — 9' broad, ovate, bipinnatifid, the 

 main rachis margined with a wing which is i" — 1" broad at the top 

 and grows narrower downwards ; pinnae in six or more distant 

 opposite pairs, upper ones simple, the lower ones with several 

 long linear pinnules on each side, the edge of the barren ones 

 spinulose-serrate ; veins simple or once forked. Ala. VI. 



\ 2. PvESIA, St. Hilaire. Veins free, rhizom.a creeping, stipes 

 sub-distant, indusium more or less double. 



4. P. aquilina, L. Rhizoma stout, wide-creeping, subterra- 

 nean ; stipes 1° — 2° high, erect, stramineous or brownish ; fronds 

 2° — 4° long, 1° — 3° wide, ternate, the three branches each bipin- 

 nate; upper pinnules undivided, the lower more or less pinna- 

 tifid. North America everywhere. I. 



Var. caudata,* Hook. Pinnules sometimes linear and entire, 

 or with less crowded segments than the type and the terminal 

 lobe linear and entire. N. J., Del., Fla. to Tex. 



