ORDER 160. FILICES. 623 



e!o33(l and subtending the sorus on three sides, opening on the fourth 

 which looks towards the apex of the segment ; veins forked, free. 



1 C. bulbifera Borah. Frond bipinnate, narrowly lanceolate, segments of the 

 Ifts. opposite, oblong, serrate, the lower one pinnatifid ; rachis bulbiferous, wing, 

 (ass ; sori roundish, placed singly at the clefts between the lobelets. In damp 

 woods, frequent. Frond 12 to 18 high, remarkable for the little bulbs produced 

 iu the axils of the rachis, which, falling to the ground, take root. Foliage nar 

 row, tapering to an acute summit. Stipe smooth. Jl. (Aspidium, Swtz.) 



2 C. fragilis Bernh. Frond bipinnate, oblong-lanceolate in outline, delicate in tex- 

 ture; Ifts. ovate-lanceolate, Begin, oblong, obtuse or acute (3 to 5'') incisely lobed 

 or pinnatifid, its lobes subentire; rachis winged by the decurrrent Ifts.; sori single; 

 at the base of each tooth ; stipe slender, longer than frond. A delicate Fern <>n 

 moist rocks, frequent. Fronds 6 to 12' high, dark green, its divisions rathet 

 remote, and with the subdivisions, considerably variable in form. Sori smali, 

 about 1 at the base of each lobe, soon naked. Jn.. Jl. (Aspidium tenue Swtz.) 



19. ONOC'LEA, L. SENSITIVE FERN". (Gr. <W, a kind of ves- 

 sel, Kheiu, to close.) Fronds sterile and fertile ; sori clustered, con- 

 fluent; proper indusium very thin, lateral; common indusium 

 formed of the segments of the frond, whose margins are revolute 

 and contracted into the form of a berry, opening, but not expand- 

 ing. Sterile fronds deeply pinnatifid, ample ; fertile bipinnate, with 

 recurved and globular, contracted segments. 



O. sensibilis L. Commoa in low grounds. Fronds nbout a foot higb, the barren 

 ones broad and somewhat triangular in outline, composed of broad, oblong, sinuate 

 divisions, the upper ones smaller, nearly entire, becoming united at base. The 

 fertile frond is very dissimilar in its form to the others, resembling a compound 

 spike enclosing the fruit in the globular segments of its short division?. Color 

 dark brown. Jl. Very sensitive to frost. 



3. OBTUSILOBATA Torr Fertile frond segments leaf-like, only partially revolute, 

 not concealing the sori. Mass., N. Y., very rare. (O. obtusiloba Schk.) 



20. ASPID'IUM, L. SHIELD FEES. (Gr. aa-ig, a small shield ; 

 from the resemblance of the indusium.) Sori orbicular, scattered, 

 terminal or lateral on the pinnate veins ; indusium orbicular, peltate 

 or reniform with a deep sinus, covering the sorus, opening all around. 



Upper half of the frond fruitful, contracted, unlike the lower sterile half Nos. 1, 2 



Upper half of the frond like the lower, not contracted, (a) 



a Frond simply pinnate, Ifts. ovate, semiauriculate No. 3 



a Frond bipinnate, segments seiniauricuhte, sharp-toothed Xos. 4, ft 



a Frond bipinnate, segments equilateral, deeply pinnatifid No. C 



a Frond pinnate with pinnatifid leaflets, (b) " 



b Segments subcoriaceous. with the sori near the mid vein Xos. T. S 



b Segments subcoriaceous, with the sori at the margin No. 9 



b Segments soft and thin, smoothish. Sori in 2 rows Nos. 10, 11 



hairy. Sori without order No. 12 



1 A. acrostichoides \Villd. Leaflets of the frond undivided, subsessile, falcate- 

 lanceolate, auriculate on the upper side at base, ciliatc-serrulate, only the upper 

 ones fertile; sori at length confluent; stipe chaffy. Common in rocky shades. 

 Frond 15 18' high, of a narrow-lanceolate outline. Stipe with loose, chaffy- 

 scales. Leaflets numerous, slightly curving upwards, 1 2' in length, (incised in A. 

 Schweinitzii Beck), the terminal ones, which alone are fruitful, are contracted iu 

 size, th3 under side becoming overspread with the sori. June Aug. 



2 A. Ludovicianum Riddell. Frond tall (2 to 4f), rigidly erect, narrowly oblong- 

 lanceolate in outline, pinnate and barren below, bipinnate. fruitful and contracted 

 above,; lower Ifts. incisely pinnatifid with very obtuse, subentire lobe?, upper with 

 distinct, oblong, obtuse, crenate-serrate segments; indusia peltate, in 2 intra- 

 marginal rows. Swamps, Ga., Fla. to La. The short stipe and long rachis chaffy. 



3 A. lonchitia "Willd. Frond pinnate, linear-lanceolate in outline, rigidly erect 



