Asplenium thelypteroides (A. acrostichoides)
Canada to Alabama and westward, in rich woods. One to three feet high.
Fronds.—Lance-shaped, tapering both ways from the middle, once-pinnate; pinnæ linear-lanceolate, deeply cut into obtuse segments; fruit-dots oblong; indusium silvery when young.
Entire frond
The Silvery Spleenwort grows in company with its kinsman, the Narrow-leaved Spleenwort, and also with many of the Aspidiums, such as the Spinulose Shield Fern, the Evergreen Wood Fern, the Christmas and Goldie's Fern. I find it growing in large patches in the rich woods, often near water, either in boggy ground or on the very edge of the clear, brown brook. Sometimes it is difficult to detect a single fertile frond in a group of plants covering many square feet of ground. This is probably owing to the deeply shaded situations which it favors, as in sunny exposures I have noticed an abundance of fertile fronds.
PLATE XVI
a Upper part of fertile frond of Silvery Spleenwort
b Portion of fruiting pinna
c Portion of pinna showing double fruit-dots
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.