FILICES. (FERNS.) 595 



Var. dilatatum, Gray. Fronds wider in outline, of a rather firmer text- 

 lire; the pinna- fewer and set farther apart, the lowest pair largest] with the 2-3 

 lower basal pinnules elongated ; segments larger and more distant ; fruit-dots 

 larger j indnsium smooth. (A. dilatatum, Stvartz. A. campylopterum, Kun-.,.) 

 — .Summits of the Black Mountains, North Carolina, llwjd. — Fronds l°-2° 

 long, 10'- 10' wide. 



5. A. Ludovicianum, Knnze. '"Fronds membranaceous, rather rigid, 

 finely glandular-pubescent beneath on the midribs, ovate, acuminate, bipinnate; 



pinna; distant, petioled, ovate or oblong, acuminate; pinnules ovate, deeply 

 pinnatifid; the lowest divisions sessile with a narrowed base; the upper ones 

 adnate, oblong, obtuse, crenately appresscd-scrrate ; serratnres acute, sometimes 

 denticulate ; fruit-dots half-way between the midrib and margin, on the upper 

 branches of the forked veins ; indusium rcniform, thiekish, entire, smooth, per- 

 sistent." Mettenius. — Florida to Louisiana, Kunze. — " Rootstock oblique; 

 fronds 2° - 3° long ; stipe straw-color, sparsely chaffy." — I have not seen this 

 Fern, which has more recently been referred by Mettenius to A. Canariensc, 

 Al. Br. 



6. A. Floridanum. Fronds thiekish, broadly lanceolate, pinnate ; lower 

 pinna; sterile, triangular-lanceolate, deeply pinnatifid, with closely set oblong, 

 obtuse divisions ; upper pinna; fertile, narrower and longer, again pinnate, with 

 oblong obtuse pinnules, distant on the narrowly winged secondary rachis ; fruit- 

 dots large, half-way between the midrib and margin ; indusium round-reniform, 

 smooth. (Nephrodium Floridanum, Hook.) — Wet woods, Florida to Louisiana. 

 — Fronds l°-2° high, the sterile ones shorter, growing in a crown from a 

 thick and scaly rootstock. — The plant has much the appearance of large 

 forms of A. cristaturn, Swartz, and may prove to be an extreme state of that 

 species. 



7. A. marginale, Swartz. Fronds evergreen, smooth, thiekish and al- 

 most coriaceous, ovate-lanceolate, bipinnate ; pinna? lanceolate from a broad 

 base ; pinnules oblong or linear-oblong, attached by a broad base to the nar- 

 rowly winged secondary rachis, entire or crenately toothed ; fruit-dots large, 

 very near the margin ; indusium round-reniform, convex, thiekish, smooth. — 

 Mountains of North Carolina, and northward. — Fronds bluish-green, l°-2° 

 long, on a short stipe, which, like the short thick rootstock, is shaggy with large 

 brown chaffy scales. 



§ 2. POLYSTICHUM, Roth, Schott. Indusium orbicular, fixed by the de- 

 pressed centre. 



8. A. acrostichoides, Swartz. Fronds evergreen, thiekish, smooth and 

 shining, lanceolate, the fertile ones tallest, pinnate ; pinna; numerous, short- 

 stalked, oblong-lanceolate, auriculate at the base on the upper side, cuneate at 

 the lower, obtuse or acute, finely serrate or incised with spinulosc-pointcd teeth ; 

 the upper pinnae of the fertile frond contracted and covered with the copious 

 fruit-dots ; indusium round, peltate, smooth and entire. — Shady and rocky 

 woods, Florida to Mississippi, and northward. — Fronds l°-2° high. Root- 

 stock and stipe very chaffy. 



