Genus 12. 



FERN FAMILY. 



29 



Wall Rue Spleenwort. Fig. 65. 



8. Asplenium Ruta-muraria L. 



Asplenium Ruta-muraria L. Sp. PI. 1081. 1753. 



Rootstock short, creeping or ascending, the small 

 evergreen leaves closely clustered. Stipes naked, 2' -3' 

 long, green throughout; blades ovate or deltoid-ovate, 

 2-5' ■ long, glabrous, evergreen, 2-3-pinnate, at least 

 below; pinnae and pinnules mostly alternate, stalked; 

 pinnules very variable in shape, size and marginal cut- 

 ting, commonly rhombic or obovate, obtuse, with the 

 margins dentate or incised, but often cuneate-spatulate, 

 the margins deeply fimbriate; veins flabellate; sori few, 

 linear-oblong, confluent when mature and covering 

 nearly the whole pinnule; membranous, delicate. 



On limestone, Vermont to southern Ontario and Michi- 

 gan, south to Alabama and Missouri. Ascends to 2100 ft. 

 in Virginia. Also in Europe, Asia and northern Africa. 

 July-Sept. Dwarf Spleenwort. Tentwort. Stone-rue. Stone- 

 fern. Rue-fern. White maiden-hair. A hybrid between this 

 species and A. Trichomanes, described originally from 

 European specimens, has been found also in Vermont. 



Asplenium montanum Willd. Mountain Spleenwort. Fig. 66. 



Asplenium montanum Willd. Sp. PI. 5 : 342. 1810. 



Rootstock short, creeping, dark-chaffy at the apex. 

 Stipes tufted, slender, naked, dark brown at the base, 

 green above, 2'~4l' long; blades deltoid-ovate to deltoid- 

 lanceolate, acuminate, rather firm, evergreen, 1-2-pin- 

 nate; lower pinnae largest, deltoid, pinnate or pinnatifid, 

 the lobes of segments ovate or rhombic-oblong, dentate, 

 often narrowly cuneate ; upper pinnae less divided, 

 merely toothed or incised ; rachis green, winged toward 

 the apex; veins obscure; sori linear-oblong, short, the 

 lower ones sometimes double, usually abundant, often 

 confluent at maturity and concealing the narrow mem- 

 branous indusia. 



On dry and moist rocks, Connecticut and New York to 

 Ohio, south to Georgia, Alabama and Arkansas. Ascends 

 to 4500 ft. in North Carolina. June-Aug. 



10. Asplenium fontanum (L.) Bernh. Rock Spleenwort. Fig. 67. 



Polypodium fontanum L. Sp. PI. 1089. 1753. 

 Asplenium fontanum Bernh. Schrad. Journ. Bot. 1799 1 : 

 314. 1799. 



' Rootstock short, ascending, clothed with narrow 

 dark scales at the apex. Stipes tufted, i'-3' long, 

 somewhat blackish at the base, especially on the 

 inner side, usually glabrous; blades linear-lanceolate, 

 broadest above the middle, 2-3-pinnate, 3' -6' long, 

 6"-i4' wide, acuminate, gradually narrowed at the 

 base, the lower pinnae often greatly reduced ; rachis 

 narrowly winged; pinnae 10-15 pairs, deltoid-lanceo- 

 late to ovate, or the lower, ones fan-shaped and 

 flabellately divided, the segments deeply dentate 

 with spinulose teeth; sori short, only 1 to 4 on each 

 segment, rarely confluent; indusia membranous, sub- 

 entire. 



On rocks, Lycoming Co., Pa., and Springfield, Ohio. 

 One of the rarest ferns of the United States ; common 

 in Europe. Summer. Called Smooth Rock-spleen wort. 



