818 ORDER 160. FILICES. 



Jn. (0. interrupta MX.) As tho sterile Ifts. unfold latest, early specimens show 

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



6. ACROS'TICHUM, L. GOLDEN FERN. (Gr. dupoc, a point, crr/fcof, 

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

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

 Fronds of various habit. 



A. aureum L. Frond pinnate, pinnae 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 W. Indies. 



7. POLYPO'DIUM, L. POLYPOD. (Gr. TTOAV$, many, noda, feet; 

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

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

 or involucre). Ferns of various habit. 



MAKGINARIA (simply pinnate) reticulate-veined, clothed with scales No. 1 



POLYPODIUM. Frond with tho veins forked, distinct, simply pinnate No. 2 



bipinnatiful Nos. 3, 4 



ternate, bipinnatifid No. 5 



1 P. inceimini Ph. Fronds deeply pinnatifid; segments alternate, linear, very 

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

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

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

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

 "W. States! and also Southern. The scales resemble the indusia of other Ferns, 

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



2 P. vulgar e L. COMMON POLYPOD. Frond deeply pinnatifid, 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. Phegopteris L. BEECH POLYPOD. Frond bipinnatifid, triangular in out- 

 line, veins ?iairy, tho lower pinnas deflexed but curving forward toward the apex; 

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

 stipe retrorsfly pubescent, rachis chaffy. Shady woods, Can. to Wis. and N. States. 

 Frond longer than wide (3 to G' by 2 to 5'). Sori small, about 4 on each seg- 

 ment. July. 



4 P. hexagonoptemm MX. TRIANGULAR POLYPOD. Frond bipinnatifid, pinnae, 

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

 dentate, glandularly puberuknt lencath, the lowest decurrent and forming a con- 

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

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

 Jl. (P. Phegopteris /?. 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. 



/3. CALCAREUM. Branches of the frond erect, rather rigid. (P. calcareum Sm.) 



8. STRUTHIOP'TERIS, Willd. OSTRICH FERN. (Gr. erpovOog, an 

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

 backwards and covering the round, confluent sori, whicl: are otherwise 

 without an indusium. Fronds bipinnatifid, the fertile piinae moniliform- 

 linear. 



