sile, 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.

[Illustration: Rusty Woodsia, _Woodsia ilvensis_]

The rusty Woodsia is decidedly a rock-loving fern, and often grows on
high cliffs exposed to the sun; its rootstock and fronds are covered with
silver-white, hair-like scales, especially underneath. These scales turn
brown in age, whence the name, rusty. As the short stipes separate at the
joints from the rootstock, they leave at the base a thick stubble, which
serves to identify the fern. Exposed rocks, Labrador to North Carolina and
westward. Rather common in New England. Said to be very abundant on the
trap rock hillocks about Little Falls, N.J., where it grows in dense tufts.

(2) NORTHERN WOODSIA. ALPINE WOODSIA

_Woodsia alpina. Woodsia hyperborea_

Fronds narrowly lanceolate, two to six inches long, smooth above, somewhat
hairy beneath, pinnate. Pinnae triangular-ovate, obtuse, lobed, the lobes
few and nearly entire. Fruit-dots rarely confluent. Indusium as in _Woodsia
ilvensis_.

[Illustration: Details of Northern Woodsia. _Woodsia alpina_]

Thought by some botanists to be a smooth form of _Woodsia ilvensis_. It
was discovered in the United States by Horace Mann, in 1863, at Willoughby
Lake, Vt. Twenty years or more later it was collected by C.H. Peck in the
Adirondacks, who supposed it to be _Woodsia_ _glabella_. In 1897 it was
rediscovered at Willoughby Lake by C.H. Pringle. New York, Vermont, Maine,
and British America. Rare.

[Illustration: Northern Woodsia, _Woodsia alpina_ (From Waters' "Ferns,"
Henry Holt & Co.)]

(3) BLUNT-LOBED WOODSIA. _Woodsia obtusa_

Fronds broadly lanceolate, ten to eighteen inches long, nearly twice
pinnate, often minutely glandular. Pinnae rather remote, triangular-ovate
or oblong, pinnately parted into obtuse, oblong, toothed segments.
Veins forked. Fruit-dots on or near the margin of the lobes. Indusium
conspicuous, at length splitting into several spreading, jagged lobes.

[Illustration: Blunt-lobed Woodsia. _Woodsia obtusa_]

This is our most common species of Woodsia and it has a wider range than
the others, extending from Maine and Nova Scotia to Georgia and westward.
On rocky banks and cliffs. The sori of this species have a peculiar beauty
on account of the star-shaped indusium, a