628 CLXIV. FILICES. Aspidium. 



* * Fronds sometimes contracted, but never paniculate or spicate. 



(of 1 scale, opening outwardly. . Aspidium. 2 



\ of 2 scales, 1 of thera marginal. . Dicksonia. 10 



5 superficial, (ofseveral scales, opening inwardly. Cheilantliea. 8 



fSori round C Indusium { beneath the sorus, fimbriate Woudsia. 4 



I or roundish. I Indusium Polypodivm. 1 



i Uransverse,on the veinlets. . . Asplemum. 3 



Frond pin- 1 Inot marginal, (parallel with the midvein. . . Woodwardia. 5 



Date, &c. ISorilinearoroblong, ; closely marginal, continuous Fteris. 7 



J apex long-acuminate, striking root in the ground. .... Asplemum. 3 



Prondentire,< apex acute, not rooting. Son hnear, scattered Scolopendnum. 6 



Frond pedate, on a black, polished, bifurcate stipe Adiantum. 9 



Thibe 1. POLiYPODIACE.aE.— Thecse furnished with a vertical, jointed, 

 elastic, and usually incomplete ring, and bursting transversely and irregu- 

 larly. 



1. POLYPODIUM. 



Gr. iro\vi, many, Jrotjj, foot; from the multitude of its roots. 



Sori roundish, scattered on various parts of the under surface of 

 the frond ; indusium none. 



1. P. iNCANUM. Pursh. (P. ceteraccinum. Mx. Acrostichum polypodoi- 

 des. Linn.) — Fronds deeply pinnatifid; segvients alternate, linear, very 



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

 bearing the fertile segments near the apex; swi solitary and distinct. — A para- 

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

 particularly of the huge sycamores, to the height of 10 — 20 feet. In the damp 

 forests along rivers, Western States ! and also Southern. 



2. P. vuLGARE. (P. Virginianum. Willd.) Common Polypod. 



Frond deeply pinnatiiid, smooth; segments lineSr-oblong, obtuse, crenu- 

 late, 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 nearly a foot high, divided into 

 alternate segments nearly to the midvein. Stipe naked and smooth. Segments 

 parallel, a little curved, about Y wide. Fruit in large, golden dots in a double 

 row, at length brownish. July. 



3. P. Phegopteris. (P. connectile. Mx.) Triangular Polypod. 

 Frond bipinnatifid, slightly pubescent and ciliate, of a triangular outline, 



the 2 lower leaflets or pinnse deflexed ; subdivisions lanceolate, obtuse, the 

 upper ones entire, lower incisely crenate, lowest adnate-decurrent ; sori minute, 

 distinct, solitary. — A fern in low woodlands, remarkable for the broad triangu- 

 lar outline of its fronds. These are about a foot in height, and rendered a little 

 hastate by the lower leaflets (which are broadest) being deflexed. Divisions 

 acuminate, connected at base by the lower segments. Stipes smooth. Aug. 



/?. connectile. (P. -connectile. Mr.) Somewhat rigid; segments of the lower 

 divisions all subentire ; veins nearly simple. 



y. liexagonopterum. (P. hexagonopterum. Mx.) Texture more delicate ; 

 segments of the lower divisions pinnatifid ; veins much forked. 



4. P. Dryopteris. Tcrnate Pplypod, 



Frond ternate, bipinnate ; branches of the frond spreading, deflexed, seg- 

 ments obtuse, subcrenate ; sari marginal ; root filiform, creeping. — This beauti- 

 ful fern grows in shady places and mountainous woods. Rare. Root black 

 and very slender. Stipe slender and delicate, smooth, nearly a foot high, divid- 

 ing into 3 light green, drooping, compound leaflets of a very delicate texture. Jl. 

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



2. ASPIDIUM. Swartz. 



Gr. naTTig, a small shield ; fiom the form and position of the indusia. 



8ori roundish or elliptical, scattered ; indusium orbicular and um- 

 bilicate (fastened at the centre and opening all around), or reniform, 

 fastened on one side and opening on the other. 



