818 ORDER ICO. FILICES. 



.Li. (0. interrupta MX.) As the sterile Ifts. unfold latest, early specimens sho\< 

 the upper Ifts. fertile. Rarely the lowest Ifts. are all fertile. 



6. ACROS'TICHUM, L. GOLDEN FERN. (Gr. aKpog, a point, 0"r(^of, 

 a line or row ; from the fruit dots and lines.) Sporanges scattered (not 

 hi sori), occupying the under surface of the whole or a part of the frond, 

 Fronds of various habit. 



A. aureum L. Frond pinnate, pinna? alternate, oblong-lanceolate, entire, equi- 

 lateral, cuneate at base, the upper bearing the fructification. In deep swamps 

 near the sea coast, Fla. (Pursh). Cultivated occasionally in the greenhouse. It 

 is a noble Fern 3 to 5f high. Common in the "\V. Indies. 



7. POLYPO'DIUM, L. POLYPOD. (Or. TTOAVC, many, ~6da, feet; 

 from the multitude of creeping roofcstocks.) Sori roundish, scattered on 

 various parts of the under surface of the frond, with no indusium (cover 

 or involucre). Ferns of various habit. 



MAKGINAEIA (simply pinnate) reticulate-veined, clothed v.-itii scales No. 1 



POLYPODIUJU. Frond with tho veini forked, distinct, simply pinnate No. 2 



bipinnatifid Kos. 3, 4 



ternate, bipinnatifid No. 5 



1 P. incanum Ph. Fronds deeply pinnatirid; segments alternate, linear, very 

 entire, obtuse, scaly beneath, the upper ones gradually smaller; stipe scaly, bear- 

 ing the fertile segments near the apex; sori solitary and distinct. A parasitio 

 fern, 3 6' high, growing on the inclined, moss-clad trunks of living trees, parti- 

 cularly of the huge Sycamore, and the Magnolias, in the clamp forests along rivers, 

 \V. States ! and also Southern. The scales resemble tho indusia of other Fernr-, 

 but have no fruit under them. The veins are invisible. 



2 P. vulgare L. COMMON POLYPOD. Frond deeply pinuatifld, smooth; segm. 

 linear-oblong, obtuse, crenulate, the upper ones gradually smaller ; sori large, 

 distinct. Rather common on shady rocks and in woods, forming tangled patches 

 with their roots which are clothed with membranous scales. Fronds 6 to 12, 

 divided into alternate segments nearly to the midvein. Stipe naked and smooth. 

 .Segments parallel, a little curved, about \' wide. Fruit in large, golden dots in a 

 double row. at length brownish. July. (P. Virginianum Willd.) 



3 P. Fhegopteris L. BEECH POLYPOD. Frond bipinnatifid, triangular in out- 

 line, veins hairy, tho lower pinntc dcflexed but curving forward toward the apex ; 

 segments linear-oblong, obtuse, entire, ciliate, the lower adnate and decurrcnt; 

 fitipe retrorsely pubescent, rachis chaffy. Shady woods, Can. to Wis. and N. States. 

 Frond longer than wide (3 to 6' by 1\ to 5'). Sori small, about 4 on each seg- 

 ment. July. 



4 P. liexagonopterum MX. TRIANGULAR POLYPOD. Frond bipiunatifid, ^mnm 

 rather distant, the lowest deflexed ; segments lanceolate, obtuse, ciliate, cremate or 

 dentate, glandularly puberulent beneath, the lowest decurrent and forming a con- 

 spicuous wing to the rachis ; stipe smooth. Moist open woodsj U. S. common 

 .South. Frond wide as long (5 to 8') triangular. Sori many on each segment. 

 Jl. (P. Phegopteris fi. ed. 2.) 



5 P. Dryopteris L. TERNATE POLYPOD. Frond ternate, bipinnate ; branches 

 of the frond spreading, deflexed, segments obtuse, subcrenate; sori marginal; 

 root filiform, creeping. This beautiful fern grows in shady places and mountain- 

 ous woods, common North. Root black and very slender. Stipe slender and 

 delicate, smooth, nearly a foot high, dividing into 3 light green, drooping, com- 

 pound leaflets of a very delicate texture. Jl. 



ft. CALCAREUM. Branches of the frond erect, rather rigid. (P. calcarcum Sin.) 



8. STRUTHIQP'TERIS, Willd. OSTRICH FERN. (Gr. orpovOoc, an 

 ostrich, TTTfpic, a fern.) Fertile fronds contracted, the margins rolled 

 backwards and covering the round, confluent sori, which are otherwise 

 without an indtisium. Fronds bipinnatifid, the fertile pinr.ffi moniliform 



