OEDEB 160 -FILICES. 821 



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

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



ATHYRIITM. Indusium oblong, snbreniform, opening half around. Frond bipinnatc...No. 7 

 ASPLKNIUM proper. Indusium narrow, straiphtish, opening only on one edge, (a) 



a Frond bipinnatifid, with numerous pinnw (leaflets). Stalks green No fl 



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. Trichomanes L. DWARF SPLEENWORT. Frond pinnate ; If is. roundish, sub- 

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

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

 Frond 36' high, lance-linear in outline, with 8 12 pairs of roundish, sessile 

 leaflets, 34" long. Fruit in several linear-oblong, finally roundish sori on each 

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



2 A. ebeiieum Willd. EBONY SPLEENWORT. Frond pinnate ; Ifls. lanceolate, sub- 

 falcate, serrate, auriculate at base on the 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 5 9' long, 1 \\' wide, linear-lanceolato 

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

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

 in short lines on each side the midrib. July. 



3 A. angustifolium Michx. Frond pinnate; Ifts. alternate, upper ones sub- 

 opposite, linear-lanceolate, serrate towards the apex, somewhat repand, the base 

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

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

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

 confluent. July. 



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

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

 small and delicate fern, ia 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 6) 2 or ^-toothed segments ; sori 

 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 the size. Segments more 

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



6 A. thelypteroides 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 side 

 the midvein, convergent b^-low, with shining, silvery indusia when young. July. 



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

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

 or lunate, arranged near the 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, the 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, Presl. WALKING FERN. (Gr. avri, like, 

 ypdmw, 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; indusiurn simple, linear. Frond 

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



