G28 CLXIV. FILICES. AsriDiUM, 



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



(of 1 scale, opening outwardly. . Aspidium. 8 



< of 2 scales, 1 ol'them miirginal. . Dicksonia. 10 



J superficial, ( of several scales, opening inwardly. CheilanUies. 8 



rSori round Undusium < beneath the sorus, fimbriate Woodsia. 4 



i or roundish. { Indusium Polypodium. 1 



i t transverse, on the vendcts. . . Asplenmm. 3 



Frond pin- I < not marginal^ < parallel with the midvein. . . Woodwardia. S 



nate, &c. I Son linear oroblong, ^closely margnial, continuous Pterin. 7 



Sapex long-acumuiate, striking root in the ground. .... Amentum. i 



Frondcntire,^ apex acute, not rooting. Son linear, scattered Scolopendnum.d 



Frond pedate, on a black, polished, bifurcate stipe. Aaianlum. a 



Tribe 1. POL.YPODIACE J3.— Thecte furnished with a vertical, jointed, 

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

 larly. 



1. POLYPODIUJM. 

 Gr. jroXtif, many, irovs, foot; from the multitude of its roots. 



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

 tlie frond ; indusium none. 



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

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



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

 bearing the fertile segments near the apex ; sori 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 pinnatifid", smooth ; segments linear-oblong, obtuse, crenu- 

 .ate, 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 \' wide. Fruit in large, golden dots in a double 

 row, at length brownish. July. 



3. P. Phf.goptehis. (P. connectile. Mr.) Triangular Polypod. 

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



the 2 lower leaflets or pinnae 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. M.x.) Somewhat rigid; segments of tlie Lower 

 divisions all subentire ; veins nearly simple. 



y. hcxagonoptcrum. (P. hexagonopterum. Mr.) Texture more delicate, 

 seo-ments of the lower divisions pinnatifid ; veins much forked. 



4. P. Dryopteris. Ternate Polypod. 



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

 ments obtuse, subcrenate; sori 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. 

 li. calcarcum. (P. calcareum. Sm.) Bra7icAcs of t/ie fvnd erect, rather ri^id. 



2. ASPIDIUM. Swartz. 



Gr. no-TTif , a small shield ; from the form and position of the indusia. 



Sori 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. 



