AsriDiUM. CLXIV. FILICES. G29 



* Frond pinnate. 



1. A. ACRosTiCHoiDEs. WiUd. (Nephrodium. Michx.) 



Leaflets of the frond distinct, alternate, suhsessile, falcate-lanceolate, aiiri- 

 culate on the upper side at base, ciliate-serrulatc, only tiie upper ones fertile; 

 sorl at length contiucnt; stipe chaffy. — Common in rocky shades. Frond 15 — 18' 

 high, of a narrow-lanceolate outline. Stipe with loose, chafiy scales. Leaflets 

 numerous, slightly curving upwards, 1 — 2' in length, the teiminal ones, which 

 alone are fruitful, are contracted in size, the under side becoming overspread 

 with the sori. June — Aug. 



/?. incisuTn. Gray. (A. Schwenitzii. Beck.') Pinnas irregularly and incisely 

 dentate ; sori mostly distinct. — N. Y., N. J. and Penn. Passes insensibly into a, 

 * * Frond pinnate with pinnaiifid leaflets. 



2. A. Thelypterj^. Willd. (A. Noveboracense. ejusd.) Shield-Fern. 



Leaflets of the frond linear-lanceolate, deeply pinnatifid, distinct, suhses- 

 sile; segments oblong, obtuse or acute, subentire, ciliate ; sori marginal, small, 

 at length confluent; stipe smooth and naked. — Damp woods. Fronds pale 

 green, thin and delicate, about a foot long and \ as wide, acuminate at apex. 

 Leaflets acuminate, becoming entire above, sometimes crossing (decussating) at 

 base. Rachis pubescent. Stipe slender, channeled on the upper side. Sori 

 in 2 marginal rows on each segment, finally nearly covering their under sur- 

 face. July. 



/?. Noveboracense. Rather paler and more delicate in texture ; leaflets more 

 narrow and remote. 



3. A. CRisTATUM. WiUd. (Nephrodium. Mx.) Crested Shield-Fern. 

 Frond nearly bipinnate, lanceolate-ovate ; leaflets subcordate, oblong-pin- 



natifid, segments oblong, obtuse, ciliate-serrate ; stipe %(i2\y. — Moist woods and 

 meadows, N. Eng., Mid. States, rather rare. Frond 12 — 18' high, pale green, 

 remarkable for its broad, ovate-lanceolate outline. Segments of the leaflets some- 

 times almost distinct, broad and obtuse, with sharp teeth. Sori large, in double 

 rows, tawny when mature, chiefly on the upper half of the frond. July. 



4. A. Lancastriense. Spreng. (A. cristatum. fi. 1st. edit.) Lancaster 

 Shield-Fern. — Stipe with a few large, oblong, torn scales, chiefly at base ; 



frond narrowly lanceolate; Uaflets subopposite, remote, short-petiolulate, broad- 

 est at base, the lower triangular-ovate ; sori large, in a single row each side the 

 midvein of each dentate segment ; indusium fixed near one side. — Woods, 

 Meriden, N. H., Rickard! to N. Y. and N. J. A beautiful fern, quite distinct 

 from the preceding, 24 — ^30' high. Frond dark green, 15 — 18' by 5 — 8'. Leaf- 

 lets gradually narrowing from base to apex. Segments nearly distinct, more or 

 less distinctly serrate-dentate, each with 1 — 25 dark-brown sori (lower leaflets 

 fruitless). July. 



5. A. GoLDiANUM. Hook. (A. Filix mas. Pursh.) Goldie's Fern. 

 Leaflets of the frond lanceolate, acuminate, deeply pinnatifid ; segments 



oblong, subacute, subfalcate, mucronate-serrate ; sori in 2 rows, each side of the 

 vein of each segment. A tall species, 2— 3f high, in rocky woods. Fronds 

 numerous, bright green, scaly upon the stipe and rachis* 5 — 10' wide. Leaflets 

 3—6' long, not widening at base, with elongated, narrow segments. July. 

 * * * Frond bipinnate. 



6. A. marginXle. Sw. (Nephrodium. Mx.) Marginal Shield-Fern. 

 Segments of the leaflets oblong, obtuse, decurrent, crenate-sinuate, repand 



at base, lower ones almost pinnatifid; sori marginal; stipe chafty. — A large, 

 handsome fern, in rocky woods, common. Frond 12 — 18' high, very .smooth 

 (rachis a little chafly), its divisions nearly opposite. Segments of the leaflets 

 distinct, near an inch long, i as wide, contracted at base, then decurrent, form- 

 ing a narrow margin along the rachis. Fruit in round dots, in regular rows 

 along the margins of the segments. Indusium large, orbicular, with a lateral 

 sinus. July.- 



7. A. TENUE. Sw. (A. fragile. Willd. Cistopteris. Bcrnh.) BnttU 

 Shield-Fern.— Segments of the leaflets oblong, obtuse or acute, incisely ser- 

 rate, approaching to pinnatifi'd, its serratures subentire; r^cAjs winged by the 



