GENUS 12. 



FERN FAMILY. 



29 



8. Asplenium Ruta-muraria L. Wall Rue Spleenwort. Fig. 65. 



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



Rootstock short, creeping or ascending, the small 

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

 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. 



9. 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'-$' long ; blades deltoid-ovate to deltoid- 

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

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

 the lobes or 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' : 

 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"iy 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 i 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-spleenwort. 



