492 FILICES. Asplenium. 



2. Asplenium ebeneum, Wiild. Screw-fern. 

 Frond pinnate ; pinnas lanceolate-oblong, somewhat falcate, serrate, sessile, auriculate at 



the base on the upper side ; stipe and rachis dark purple, smooth and shining. — Willd. sp. 

 5. p. 329 ; Pursh, ft. 2. 666 ; Bigel. jl. Bost. p. 393 ; Torr. cornpend. p. 383 ; Beck, hot. 

 p. 453 ; Darlingt. fl. Cest. p. 581. A. trichomanoides, Michx. jl. 2. p. 265. 



An upright straight fern, 8-14 inches high ; the frond lanceolate-linear in outline. Pinnae 

 numerous, 5-8 lines long, often slightly twisted, so that at a distance the frond has a spiral 

 appearance. Veins pinnate, forked, free. Sori 12-20 on each pinna, oblong, finally confluent. 

 Involucre very thin and membranaceous. 



Rocky woods : common. Fr. July. 



3. Asplenium angustifolium, Michx. Narrow-leaved Sj)leemvort. 

 Frond pinnate ; pinns linear-lanceolate, acute, crenate-serrulate, somewliat repand ; the 



base truncate on the lower side, rounded on the upper. — Miclix. Jl. 2. p. 265 ; " Schk. Fit. 

 t. 67 ^f- 69 " ; Pursh, Jl. 2. p. 666 ; Bigel. Jl. Bost. p. 393 ; Torr. compend. p. 383 ; Beck, 

 bat. p. 452. 



About 18 inches or 2 feet high, erect. Stipe and rachis minutely dotted. Sterile frond 

 oblong in outline ; the pinnre 2-4 inches long and about half an inch broad, very thin and 

 delicate, nearly sessile ; the veins forking near their base, and then often again divided, but 

 never anastomosing. Fertile fronds much narrower, attenuate at the apex : pinnae 1-2 inches 

 long, lanceolate-linear, often somewhat falcate ; the lower ones rather erect. Sori oblong- 

 linear, arising from the upper fork of the veins, closely approximated, and extending from 

 near the midrib to within a short distance of the margin, finally confluent. Involucre vaulted, 

 thick, and somewhat leathery. 



Shady moist woods, western and northern parts of the State ; also on Long Island, about 

 three miles from Brooklyn. Fr. July. 



♦• AcROPTERis, Link. Fronds pinnate, bipinnale or forked ; segments laciniate or serrate ; midrib iridefinite or wanting; 



the veins radiating from the base, 



4. Asplenium Ruta-muraria, Linn. Wall-rue Spleenwort. 

 Frond bipinnate below, simply pinnate above; segments rhomboid-cuneate, toothed at the 



extremity. — Linn. sp. 2. p. 1081 ; Engl. hot. t. 150 ; Michx. Jl. 2. p. 268 ; Pursh, Jl. 2. 

 p. 667 ; Bigel. fl. Bost. p. 393 ; Torr. compend. p. 383 ; Beck, hot. p. 453 ; Darlingt. Jl. 

 Cest. p. 582. 



Whole plant 2-4 inches long, smooth ; the frond ovate in outline, somewhat rigid, glaucous 

 green : segments few and distant and somewhat ternate, 2-4 lines long, tapering at the base 

 in a petiole ; the exiremity cut into irregular obtuse or acute teeth. Sori linear-oblong, large 

 for the size of the frond. Involucre membranaceous. 



Limestone rocks, usually in shady situations : rare. Fr. July. In all respects similar to 

 the European plant, except that it is usually smaller. 



