[Illustration: Fragile Bladder Fern, Fruited Portion]
[Illustration: Fragile Bladder Fern. Cystopteris fragilis (Wakefield, Mass.)]
KEY TO THE WOODSIAS
Stipes not jointed:
Indusium ample, segments broad, frond without hairs.
Obtuse Woodsia.
Pinnæ hispidulous, with white jointed hairs beneath.
Rocky Mountain Woodsia.
Fronds bright green, pinnæ glabrous, oblong.
Oregon Woodsia.
Fronds dull green, lanceolate, glandular beneath.
Cathcart's Woodsia.
Stipes obscurely jointed near the base:
Fronds more or less chaffy, pinnæ oblong to ovate,
crowded. Rusty Woodsia.
Fronds linear, smooth, pinnæ deltoid or orbicular.
Smooth Woodsia.
Fronds lanceolate, a few white scales beneath; pinnæ
deltoid-ovate. Alpine Woodsia.
[THE WOODSIAS]
Small, tufted, pinnately divided ferns. Fruit-dots borne on the back of simply forked, free veins. Indusium fixed beneath the sori, thin and often evanescent, either small and open, or early bursting at the top into irregular pieces or lobes. (Named for James Woods, an English botanist.)
(1) RUSTY WOODSIA. Woódsia ilvénsis
Fronds oblong-lanceolate, three to ten inches high, rather smooth above, thickly clothed underneath with rusty, bristle-like chaff. Pinnate, the pinnæ crowded, sessile, cut into oblong segments. Fruit-dots near the margin often confluent at maturity. Indusium divided nearly in the center into slender hairs which are curled over the sporangia. Stipes jointed an inch or so above the rootstock.