WOODSIA. CLXIV. FILICES. 631 



in outline, with 8 12 pairs of roundish, sessile leaflets, 3 4" long. Fruit in 

 several linear-oblong, finally roundish sori on each leaflet, placed oblique to the 

 midvein. July. 



5. A. THELiPTERolDEs. Michx. Silvery Spleenwort. 



Frond bipinnatifid ; Ifts. pinnatifid, oblong-lanceolate, acuminate ; segments 

 oblong, obtuse, sermte-crenate ; sori in parallel, oblique lines. A fine, large 

 fern, on shady banks of streams. Fronds 1J 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 i' long. Sori arranged 

 in 2 rows on each segment, one on each side the midvein, convergent below, 

 with shining, silvery indusia when young. July. 



6 A. FILIX-FOBMINA. Bernh. (Aspidium Filix-fo3mina and asplenoides. Sw. 



A. angustum. W.) Frond bipinnate -,.lfts. lanceolate, acuminate ; seg. ob- 

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

 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 23 teeth at the summit. 

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

 dark brown hue. July. 



7. A. RUTA-MURARIA. Wall-rue Spleenwort. 



Frond bipinnate at base, simply pinnate above ; Ifts. small, petiolate, cu- 

 neate, obtusely dentate above. An extremely small and delicate fern, in dry, 

 rocky places. Frond 2 3' high, J as wide, smooth, growing in tufls, somewhat 

 coriaceous. Segments usually 3 on each leaflet, less than J' long. Stipe flat 

 and smooth. Sori linear-oblong, slightly oblique, of a rusty-brown color, finally 

 confluent. July. 



8. A. MONTANUM. Willd. (A. Adiantum-nigrum. Michx.) 



Frond glabrous, bipinnate ; Ifts. oblong-ovate, pinnatifid ; seg. 2 3-toothed 

 at the apex ; sori linear, finally confluent. Mountain rocks, Bethlehem, Penn. 

 Schwenitz (fide Deck), S. to Car., W. '.o Ky. Fronds growing in tufts, 4 8' 

 high, narrowly 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. 



4. WOODSIA. Brown. 



In honor of Joseph Woods, an excellent English botanist 



Sori roundish, scattered ; indusium beneath the sorus, open, with 

 a multifid or fringed margin, including the pedicellate thecse, like a 

 calyx. 



1. W. ILVENSIS. Br. (Polypodium. Willd.) 



Frond pinnate, leaflets pinnatifid, lanceolate ; segments ovate-oblong, ob- 

 tuse ; sori near the margin, at length confluent ; rachis and stipe chaffy. Grow- 

 ing in tufts, on rocks and in dry woods. Fronds 5 or 6' high, on chaffy and 

 woolly stipes, most chaffy at base. Foliage 3 or 4' long, as wide, oblong- 

 lanceolate in outline, woolly or chaffy beneath, with opposite and alternate leaf- 

 lets about an inch in length. The lower leaflets are pinnatifid, upper ones 

 wavy on the margin or entire. June. 



2. W. PERRINIANA. Hook. & Grev. (Hypopeltis obtusa. Tvrr.) 

 Frond subbipinnate, minutely glandular-pilose; segments of the kaflcts pin- 



natifid; ultimate segments roundish-oblong, obtuse, bidentate ; sori submarginal- 

 stipe somewhat chaffy. About a foot high, among and on rocks. Fronds lance 

 oblong in outline, 3 times as long as wide. Segments of the leaflets crenate- 

 serrate, the lower ones distinct, upper confluent. Sori orbicular, becoming 

 nearly confluent, each subtended by a half round indusium notched into little 

 teeth on the margin. July. 



3. W. HYPERBOREA. Br. (Polypodium. Willd.) Flower-cup Fern. 

 Frond pinnate ; Ifts. suborbicular, subcordate, 3-parted or incisely pinnati- 

 fid, cuneate at base, rough pilose beneath. A very small species, much resent- 



