ORDER 1GO ^-FILICES. 821 



the upper or forward side of the lateral veins and opening towards the 

 midvein. Ferns of various habit. Veins forked or pinnate. 



ATIIYRIUM. Imlusium oblong, subreniform, opening half around. Frond nipinnatc...No. 7 

 ASPLKNIUM proper. Imhisiiiia narrow, straightish, opening only on one edge, (a) 



a Frond bipinnatirid, with numerous pinna- (leaflets). Stalks green. . . . No. 6 



a Frond bipinnatifid, with few divisions. Stalks greenish Nos. 4, 5 



a Frond simply pinnate, thin, large, with green stalks No. 3 



subcoriaceous, with dark purple stalks Nos. 1, 2 



1 A. Trich6manes L. DWARF SPLEENWORT. Frond pinnate ; If Is. roundish, sub- 

 sessile, small, roundish-obovate, obtusely cuneato and entire at base, crenate above ; 

 stipe black and polished. A small and delicate fern, forming tufts on shady rocks. 

 Frond 3 6' high, lance-linear in outline, with 8 12 pairs of roundish, sessily 

 leaflets, 3 4" long. Fruit in several linear-oblong, finally roundish sori on each 

 leaflet, placed oblique to tho midvein. July. (A. melanocaulon Muhl.) 



2 A. ebeneum Willd. EBONY SPLEENWORT. Frond pinnate ; Ifts. lanceolate, sub* 

 falcate, serrate, auriculate at base on tho upper side ; stipe smooth and polished. 

 A beautiful fern, in dry woods, hills. Fronds 8 14' high, on a slender stipe of 

 a shining brown or black color. Foliage 59' long, 1 !-' wide, linear-lanceolate 

 in outline. Leaflets near an inch in length, rather acuminate and curved at apex, 

 dilated at base on the upper side, and sometimes on tho lower. Fruit arranged 

 in short lines on each side the midrib. July. 



3 A. angustifolium Michx. Frond pinnate; Ids. alternate, tipper ones sub- 

 opposite, linear-lanceolate, serrate towards tho apex, somewhat repand, the bases 

 truncate on the upper side and rounded on tho lower. In low woods, frequent, 

 Vt. to Ga. Fronds thin, fragile, 1 2 f high, ia tufts, the outer ones barren, inner 

 fertile. Sori large, diverging from tho midrib, parallel with the veins, at length 

 confluent. July. 



4 A. Ruta-muraria L. Frond bipinnate at base, simply pinnate above; Ifts. 

 small, petiolate, cuneate at base, erose-dentate at the blunt apex. An extremely 

 small and delicate fern, in dry, rocky places. Frond 2 3' high, - as wide, smooth, 

 growing in tufts, somewhat coriaceous. Segments usually 3 on each leaflet, less 

 than ' long. Stipe flat and smooth. Sori linear-oblong, slightly oblique, of a 

 rusty-brown color, finally confluent. July. 



5 A. montanum Willd. (A. Adiantum-nigrum. Michx.) Frond glabrous, 

 bipinnate ; Ifts. oblong-ovate, parted into a few (5 or G) 2 or '&-lootlied segments ; son 

 linear, finally confluent. Mountain rocks, Penn. to Car. (Curtis), W. to Ky. 

 Fronds growing in tufts, 4 8' high, rhombic or oblong-lanceolate in outline, 

 mostly bipinnate, but more or less divided according to tho size. Segments more 

 obtuse than in the foreign A. Adiantum-nigrum. July. 



6 A. thelypteroidea Michx. SILVERY SPLEENWORT. Frond bipinnatifid ; Ifts. 

 pinnatifid, oblong-lanceolate, acuminate ; segments oblong, obtuse, serrate-crenate ; 

 sori in parallel, oblique lines. A fine, large fern, on shady banks of streams. 

 Fronds 1^ 3f high, of an ovate-acuminate outline, on a slightly chaffy, pale stipe. 

 Leaflets distinct and rather remote, narrow, 4 6' long. Segments rounded at the 

 end, near %' long. Sori arranged in 2 rows on each segment, one on each sido 

 the midvein, convergent below, with shining, silvery indusia when young. July. 



7 A. Filix-fcemina Bernh. Frond bipinnate ; Ifts. lanceolate, acuminate ; seg. 

 oblong-lanceolate, deeply cut-pinnatifid ; ultimate seg. 2 3-toothed ; sori reniform 

 or lunate, arranged near tho veins ; stipe smooth. A delicate, finely-divided fern 

 in moist woods. Fronds 1 2f high, with subopposite divisions. These are sub- 

 divided into distinct, obtuse segments, which are themselves cut into oblong, deep 

 serratures, and lastly, tho serratures are mostly with 2 3 teeth at the summit. 

 Sori large, at first in linear curves, finally confluent, giving the whole frond a dark 

 brown hue. July. (Aspidium, Swtz.) 



15. ANTIGRAM'MA, Prcsl. WALKING FERN. (Gr. avri, like, 

 ypdnf-ia, writing ; said of the fruit dots.) Sori linear or oblong, scat- 

 tered without order on the transverse veins, oblique at various angles, 

 often in pairs and facing each other; indusium simple, linear. Frond 

 simple, veins reticulated in the midst, forked and free only ia the margin. 



