GENUS 12. 



FERN FAMILY. 



29 



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



Asplcniinn Ruta-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. 



g. Asplenium montanum Willcl. 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 indtisia. 



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. 



A 



Polypodiinn fontanum L. Sp. PI. 1089. 1/53- 

 Asplenium fontanum Bernh. Schrad. Journ. Bot. I799 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"-rl' 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. 



