818 Ordee 160.— FILICES. 



Jn. (0. interrupta Mx.) As the sterile Ifta. unfold latest, early specimens show 

 the upper Ifits. fertile. Earely the Joweat Ifts. are all fertile. 



6. ACROS'TICHUM, L. Golden Fern. (Gr. drepd?, a point, ffT(>;o?. 

 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. ai^Lieum L. Frond pinnate, pinuse alternate, oblong-lanceolate, entire, equi- 

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

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

 is a noble Fern 3 to 5f high. Common in tlie "W. Indies. 



7. POLYPO'DIUM, L. Polypod. (Gr. TroAvf, many, iroSa, 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. 



§ Mabginaria (siniijly pinnate) reticulate-veined, clothed with scales Wo. 1 



§ Poi,YPODiu.y. Pi'ond ivitli the veins foriied, distinct, — simply pinnate No. 3 



— bipinnatiiid Nos. 3, 4 



— teniate, bipinnatiiid No. 5 



1 P. incanum Ph. Fronds deeply pinnatifld; 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 parasitic 

 fern, 3 — 6' high, growing on the iuolined, 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. vulgare L. Common Polypod. Frond deeply pinnatifld, smooth ; segm. 

 linear-obloBg, 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 aro 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. Virgiuianum Willd.) 



3 P. Phegopteris L. Beech Polypod. Frond bipinnatifid, triangular in out- 

 line, veins hairy, the lower pinn33 deflexed but curving forward toward the apex ; 

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

 stipe retrorsely pubescent, rachis chaffy. — Shady w-oods, Can. to Wis. and N. States. 

 Frond longer than wide (3 to 6' by 2 J to 5'). Sori small, about 4 on each seg- 

 ment. July. 



4 P. hexagonopterum Mx. Teiangulab Polypod. Frond bipinnatifid, pinncB 

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

 dentate, glandularly puherulent ieneath, 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. Sbri many on. each segment. 

 Jl. (P. Phegopteris (3. od. 2.) 



5 P. Dry6pteri3 L. Ternate Polypod. Frond ternate, bipinnate; branches 

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

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

 ous woods, common North. Root blaclc 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. 



/?. calcareum. Branches of the frond erect, rather rigid. (P. oalcaroum Sm.) 



8. STRUTHIOP'TERIS, Willd. Ostrich Fern. (Gr. aTpovd6g,!m 



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

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

 without an indusium. — Fronds bipinnatifid, the fertile pinnsB moniliform- 

 linear. ^ 



