The ferns of this group, not counting the small fragrant fern, prefer the
woods or at least shady places. Although the genus _Polýstichum_ represents
the true shield ferns, the wood ferns are also thus designated, as their
indusia have nearly the shape of small, roundish shields. The old generic
name for them all was _Aspídium_ (meaning shield), first published in 1800.
For a long time its chief rival was _Nephròdium_ (kidney-like), 1803. Many
modern botanists have preferred the earlier name _Dryópteris_ (1763),
meaning oak fern, alluding, perhaps, to its forest-loving habits.
THELÝPTERIS, still earlier (1762), may supersede the others.
[Illustration: Marginal Shield Fern. Aspidium marginale (From Woolson's
"Ferns," Doubleday, Page & Co.)]
[Illustration: Sori of Marginal Shield Fern]
(1) MARGINAL SHIELD FERN, EVERGREEN WOOD FERN
_Aspídium marginàle_. THELÝPTERIS MARGINÀLIS
_Dryópteris marginàlis. Nephròdium marginàle_
Fronds from a few inches to three feet long, ovate-oblong, somewhat
leathery, smooth, twice pinnate. Pinnæ lanceolate, acuminate, broadest just
above the base. Pinnules oblong, often slightly falcate, entire or toothed.
Fruit-dots large, round, close to the margin. Rocky hillsides in rich
woods, rather common throughout our area. The heavy rootstock rises
slightly above the ground and is clothed at the crown with shaggy, brown
scales. Its rising caudex, often creeping for several inches over bare
rocks, suggests the habit of a tree fern. In early spring it sends up a
graceful circle of large, handsome, bluish-green blades. The stipes are
short and densely chaffy. No other wood fern endures the winter so well.
The fronds burdened with snow lop over among the withered leaves and
continue green until the new ones shoot up in the spring. It is the most
valuable of all the wood ferns for cultivation.
(2) THE MALE FERN
_Aspídium Fìlix-mas_. THELÝPTERIS FÌLIX-MAS
_Dryópteris Fìlix-mas. Nephròdium Fìlix-mas_
Fronds lanceolate, pinnate, one to three feet high growing in a crown from
a shaggy rootstock. Pinnæ lanceolate, tapering from base to apex. Pinnules
oblong, obtuse, serrate at the apex, obscurely so at the sides, the basal
incisely lobed, distant, the upper confluent. Fruit-dots large, nearer the
mid vein than the margin, mostly on the lower half of each fertile segment.
The male fern resembles the marginal shield fern in outline, but the fronds
are thinner, are not evergreen, and the sori are near the midvein. Its use
in medicine is of long standing. Its rootstock produces the well-known
_fìlix-mas_ of the pharmacist. This has tonic and astringent properties,
but is mainly prescribed as a vermifuge, which is one of the names given to
it. In Europe it is regarded as the typical fern, being oftener mentioned
and figured than any other. In rocky woods, Canada, Northfield, Vt., and
northwest to the great lakes, also in many parts of the world.
[Illustration: The Male Fern. _Aspidium Filix-mas_ (Vermont)]
[Illustration: FIG. 33G. _Aspidium filix mas_ 1, Illustration
exhibiting general habit; a, young leaves: 2, transverse section of
rhizome showing the conducting bundles a: 3, portion of the leaf bearing
sori; a indusium b, sporangia; 4, longitudinal; 5, transverse section of a
soris; a, leaf; b, indusium; c, sporangia: 6, a single sporangium; a,
stalk; c, annulus; d, spores. (After WOSSIDLO OFFICINAL) From a German
print, giving details]
(3) GOLDIE'S FERN
_Aspidium Goldiànum_. THELYPTERIS GOLDIÀNA
_Dryopteris Goldiàna. Nephrodium Goldiànum_
Fronds two to four feet high and often one foot broad, pinnate, broadly
ovate, especially the sterile ones. Pinnæ deeply pinnatifid, broadest
in the middle. The divisions (eighteen or twenty pairs) oblong-linear,
slightly toothed. Fruit-dots very near the midvein. Indusium large,
orbicular, with a deep, narrow sinus. Scales dark brown to nearly black
with a peculiar silky lustre.
A magnificent species, the tallest and largest of the wood ferns. It
delights in rich woodlands where there is limestone. Its range is from
Canada to Kentucky. While not common, there are numerous colonies in New
England. It is reported from Fairfield, Me., Spencer and Mt. Toby, Mass.,
and frequently west of the Connecticut River. We have often admired a large
and beautiful colony of it on the west side of Willoughby Mountain in
Vermont. It is easily cultivated and adds grace and dignity to a fern
garden.
[Illustration: Goldie's Shield Fern. _Aspidium Goldianum_ (Vermont, 1874.
C.G. Pringle) (Herbarium of G.E. Davenport)]
[Illustration: Goldie's Fern (From Woolson's "Ferns," Doubleday, Page &
Co.)]
(4) THE CRESTED FERN
_Aspidium cristàtum_. THELÝPTERIS CRISTÀTA
_Dryopteris cristàta. Nephrodium cristàtum_
Fronds one to two feet long, linear-oblong or lanceolate, pinnate, acute.
Pinnæ two to three inches long, broadest at the base, triangular-oblong,
or the lowest triangular. Divisions oblong, obtuse, finely serrate or
cut-toothed, those nearest the rachis sometimes separate. Fruit-dots large,
round, half way between the midvein and the margin. Indusium smooth, naked,
with a shallow sinus.
The short sterile fronds, though spreading out gracefully, are conspicuous
only in winter; while the fertile fronds, tall, narrow and erect, are found
only in summer.
It is one of our handsomest evergreen ferns and even the large sori, with
their dark spore cases and white indusia, are very attractive. The fertile
pinnæ have a way of turning their faces upward toward the apex of the frond
for more light. In moist land, Canada to Kentucky.
Var. _Clintoniànum_. Clinton's Wood Fern. Resembles the type, but is in
every way larger. Divisions eight to sixteen pairs. Fruit-dots near the
midvein, the sides of the sinus often overlapping. South central Maine to
New York and westward. "Rare in New England attaining its best development
in western sections." (Dodge.) Mt. Toby, Mass., Hanover, N.H. July. Fine
for cultivation.
[Illustration: Crested Shield Fern. _Aspidium cristatum_ (Reading, Mass.,
Kingman)]
[Illustration: The Crested Shield Fern. _Aspidium cristatum_]
[Illustration: Clinton's Wood Fern. _Aspidium cristatum_, var.
_Clintonianum_ (Gray Herbarium)]