rPnilP V FERTILE AND STERILE FRONDS LEAF-LIKE AND SIMILAR ; 

 UKUUh" V SPORANGIA IN LINEAR OR OBLONG FRUIT-DOTS 



to the deeply shaded situations which it favors, as 

 in sunny exposures I have noticed an abundance of 

 fertile fronds. 



Its color is a dull green, the silvery indusia on the 

 lower surfaces of the pinnae giving the plant its Eng- 

 lish title. Although usually its fronds are larger, 

 their outline, tapering as it does both ways from the 

 middle, somewhat suggests that of the New York 

 Fern. It is readily identified, as the oblong or linear 

 fruit-dots at once proclaim it a Spleenwort, and no 

 other member of this tribe has fronds of the same 

 shape. 



Although it cannot be classed among the rare 

 ferns, it is absent from many promising localities, 

 and is associated in my mind with especially suc- 

 cessful expeditions. 



26. RUE SPLEENWORT. WALL RUE 



AspUnium Ruta-muraria 



A small rock fern, growing on limestone, Vermont to Michigan 

 and southward. Four to seven inches long, with green, slender, 

 tufted stalks. 



Fronds. — Triangular-ovate, smooth, evergreen, twice or thrice- 

 pinnate below ; pinna cut into stalked pinnules ; fruit-dots con- 

 fluent at maturity, covering nearly the whole lower surface of pin- 

 nules; indusium delicate. 



My first acquaintance with the little Rue Spleen- 

 wort in its own home dates back to the memorable 

 day when we discovered the new station for the 

 Hart's Tongue. 



126 



