Obdeb 160.— FILICES. 823 



closed 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 Bornh. Frond bipinnate, narrowly lanceolate, segments of tho 

 lfts. opposite, oblong, serrate, ^ho lower one pinnatifid; rachis bulbiferous, wing- 

 less ; 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 

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

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



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

 ture; lfts. ovate-lanceolate, segru. oblong, obtuse or acute (3 to 5"), incisely lobed 

 or pinnatifid, its lobes subentiro ; rachis tuinged by the decurrent lfts. ; sori single 

 at the base of each tooth; stipe slender, longer than frond. — A delicate Fein on 

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

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

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



19. ONOC'LEA, L. Sensitive Fern. (Gr. uvog, a kind of vessel, 

 A'AeiO), to close.) Fronds sterile and fertile; sori clustered, confluent ; 

 proper indnsium very thin, lateral ; common indnsium formed of the 

 segments of the frond, whose margins are revolute 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. sensibili3 L. Common in low grounds. Fronds about a foot high, tho barren 

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

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

 fertilo frond is very dissimilar ia its form to the others, resembling a compound 

 spiko enclosing the fruit in the globular segments of its short divisions. Color 

 dark brown. Jl. — Very sensitive to frost. 



/?. OUTUSILOBATA Torr. Fertile frond segments leaf-like, only partially revolute, 

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



20. ASPID'IUM, L. Shield Fern. (Gr. aarrtg, a small 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. 



§ Upper half of the frond fruitfnl, contracted, unlike the lower sterile half Nos. I, 2 



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



a Frond simply pinnate, lfts. ovate, seiniauriciilate No. 3 



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



a Frond bipinnate, segments equilateral, deeply pinnatilid No. 8 



a Frond pinnate with pinnatifid leaflets, (b) 



b Segments subcoriaceous, with the soii near the midvein Nos. 7, 8 



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



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



— hairy. Sori without order No. 12 



1 A. acrostichoides "Willd. Lea/lets 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 are fruitful, are contracted in 

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



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

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

 above; lower lfts. incisely pinnatifid with very obtuse, subentire lobes, upper with 

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

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



3 A. lonchitis Willd. Frond pinnate, linear-laDceolate in outline, rigidly erect 



