| GROUP V | FERTILE AND STERILE FRONDS LEAF-LIKE AND SIMILAR; |
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 pinnæ giving the plant its English 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 successful expeditions.
26. RUE SPLEENWORT. WALL RUE
Aspenium 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; pinnæ cut into stalked pinnules; fruit-dots confluent at maturity, covering nearly the whole lower surface of pinnules; indusium delicate.
My first acquaintance with the little Rue Spleenwort in its own home dates back to the memorable day when we discovered the new station for the Hart's Tongue.
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