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.
[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 alpìna. Woodsia hyperbòrea_
Fronds narrowly lanceolate, two to six inches long, smooth above, somewhat
hairy beneath, pinnate. Pinnæ 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_ _glabélla_. 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 obtùsa_
Fronds broadly lanceolate, ten to eighteen inches long, nearly twice
pinnate, often minutely glandular. Pinnæ 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, as it splits into fragments. Var.
_angústa_ is a form with very narrow fronds and pinnæ. Highlands, New York.
The type grows in Middlesex County, Mass., but is rare.
(4) SMOOTH WOODSIA. _Woodsia glabélla_
Fronds two to five inches high, very delicate, linear, pinnate. Pinnæ
remote at the base, roundish-ovate, very obtuse with a few crenate lobes.
Stipes jointed, straw-colored. Hairs of the indusium few and minute.
[Illustration: Smooth Woodsia. _Woodsia glabella_ (Willoughhy Mountain, Vt.
G.H.T.)]
On moist, mossy, mostly calcareous rocks, northern New England, Mount
Mansfield, Willoughby, and Bakersfield Ledge, Vt., Gorham, N.H., also
Newfoundland, New York, and far to the northwest. Not very common. It
differs from the alpine species by the absence of scales above the joint.
As the name implies, the plant is smooth, except for the chaffy scales at
or near the rootstock, which mark all the Woodsias, and many other ferns,
and which serve as a protective covering against sudden changes in extremes
of heat and cold.
(5) OREGON WOODSIA. _Woódsia oregàna_
Fronds two to ten inches high, smooth, bright green, glandular beneath,
narrowly lance-oblong, bipinnatifid. Pinnse triangular-oblong, obtuse,
pinnatifid. Segments ovate or oblong, obtuse, crenate, the teeth or margin
nearly always reflexed. Indusium minute, concealed beneath the sorus,
divided into a few beaded hairs.
Like the obtuse Woodsia this fern has no joint near the base of the stipe,
but is much smaller and has several points of difference. Limestone cliffs,
Gaspé Peninsula, southern shore of Lake Superior, Colorado, Oregon to the
northwest. Its eastern limit is northern Michigan.
(6) ROCKY MOUNTAIN WOODSIA. _Woódsia scopulìna_
Fronds six to fifteen inches long [smooth], lanceolate, pinnatifid. Pinnæ
triangular-ovate, the lowest pair shortened. Under surface of the whole
frond hispidulous with minute, white hairs and stalked glands. Indusium
hidden beneath the sporangia, consisting mostly of a few hair-like
divisions.
In crevices of rocks, mountains of West Virginia, Gaspé Peninsula, Rocky
Mountains, and westward to Oregon and California.
(7) CATHCART'S WOODSIA. _Woodsia Cathcartiàna_
Fronds eight to twelve inches high, lanceolate, bipinnatifid, finely
glandular-puberulent. Pinnse oblong; the lower distant segments oblong,
denticulate, separated by wide sinuses.
Rocky river banks, west Michigan to northeast Minnesota.