ORDER 160. FlHCES. 823 



closed and subtending the sorns on throe sides, opening on the fourth 

 Avhich loots towards the apex of the segment ; veins forked, free. 



1 C. bulbifera Bernh. Frond bipinnato, *nrrowly lanceolate, segments of the 

 Ifts. opposite, oblong, serrate, the lower C'** pinnatifid; rachis bulbiferous, wing- 

 less ; sori roundish, placed singly at tho oaefts between the lobelets. In damp 

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

 in the axils of the rachis, which, falling to the ground, take root. Foliage narrow, 

 tapering to an acute summit. Stipe six>joth. JL (Aspidium, Swtz). 



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

 ture; Ifts. ovate-lanceolate, segm. oK-ong, obtuse or acute (3 to 5"), incisely lobed 

 or pinnatifid, its lobes subentirc ; rw.kis winged by the decurrent If is. / sori singlo 

 at the base of each tooth ; sti]?? "tender, longer than frond. A delicate Fern on 

 moist rocks, frequent. Fronds % to 12' high, dark green, its divisions rather 

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

 about 1 at the base cf each lobe, soon naked. Jn., JI. (Aspidium tcnue Swtz.) 



19. ONOC'LEA, L. SENSITIVE FERN. (Gr. ovog, a kind of vessel, 

 /t/Uto), to close.) Fronds sterile and fertile ; sori clustered, confluent ; 

 proper indusium very tbia, lateral ; common indusium formed of tho 

 segments of the frond, whose margins are revoluto and contracted into 

 the form of a berry, opening, but not expanding. Sterile fronds deeply 

 pinnatifid, ample ; fertile bipinnate, with recurved and globular, con- 

 tracted segments. 



O. sensibilis L. Common in low grounds. Fronds about a foot high, the barren- 

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

 divisions, tho upper ones smaller, nearly entire, becoming united at base. Tho 

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

 spike enclosing the fruit in the globular segments cf its short divisions. Color 

 dark brown. Jl. Very sensitive to frost. 



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

 not concealing the sort Mass., N. Y., very rare. (0. obtusiloba Schk.) 



20. ASPID'IUM, L. SHIELD FERN. (Gr. ocnrfc a Email shield ; 

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

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

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



TTpper 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, semiauricnlate No. 3 



a Frond bipinnate, segments seiniauriculate, sharp- toothed Nos. 4, 5 



a Frond bipinnate, segments equilateral, deeply pinnatifid No. 6 



a Frond pinnate with pinnatifid leaflets, (b) 



b Segments subcoviaceous, with the sori near the midvein Nos. 7, 8 



b Segments subcoriaccous, with tlie sod at the margin No. 9 



b Segments soft and thin, stnoothish. Sori in 2 rows JJos. 10, 11 



hairy. Sori without order No. 12 



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

 lanceolate, auriculate on the upper side at base, ciliate-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 aro fruitful, are contracted ia 

 size, tha under sido becoming overspread with tho 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 lobes, 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 



