Chapter II: Part 2

_Pteris atropurpurea_, Linnæus, Sp. Pl., p. 1534.—Michaux, Fl. Bor.-Am.,
ii., p. 261.—Swartz, Syn. Fil., p. 106.—Schkuhr, Krypt. Gew., p.
93, t. 101.—Willdenow, Sp. Pl., v., p. 375.—Pursh, Fl. Am. Sept.,
ii., p. 668.

_Platyloma atropurpureum_, J. Smith.—Torrey, Fl. New York, ii., p. 488.

_Allosorus atropurpureus_, Kunze, in Sill. Journ., July, 1848, p. 86;
Linnæa, xxiii., p. 218.—Gray, Manual, ed. ii., p. 591.—Mettenius,
Fil. Hort. Lips., p. 44.

_Pellæa mucronata_, Fée, 9me Mém., p. 8.

_Pellæa glabella_, Mettenius & Kuhn, in Linnæa, xxxvi., p. 87.

_Pteris spiculata_, Schkuhr, Krypt. Gew., p. 92, t. 100.

_Pteris Adianti facie, caule ramulis petiolisque politiore nitore
nigricantibus, etc._, Gronovius, Fl. Virginica, ed. i., p. 197.

Hab.—Crevices of shaded calcareous rocks; from Canada to the Rocky
Mountains of British America, and southward to Alabama, Arkansas,
Indian Territory and Arizona. It has been found in several parts of
Mexico, and even in South America (“Andes of Mecoya, Pearce,” according
to _Synopsis Filicum_). It was collected by John Clayton about 1736,
“on the shore of the river Rappahannock in a shady place by the root of
a juniper near the promontory called Point Lookout,” and I take
pleasure in giving it an English name in his honor.

Description:—The root-stock of this fern is rather short, usually somewhat nodose, and densely chaffy with very narrow long-pointed soft bright-brown scales, which in the specimens examined are destitute of midnerve.

The stalks are rigid and wiry, terete, nearly black in color, but with a slight reddish tinge, and usually more or less pubescent with very narrow chaffy hairs, which are often more abundant and harsher along the rachises, making them almost hirsute. _Pellæa glabella_ was founded on specimens from Missouri and the North-West, which had the stalk perfectly smooth, and the chaff of the root-stock a trifle wider than usual. The section of the stalk shows a single U-shaped fibro-vascular bundle, and a strong outer sclerenchymatous sheath.

The fronds are developed late in the Spring, and remain green through the next Winter. They are almost coriaceous in texture, smooth and dark-bluish-green above, paler, and sometimes slightly chaffy beneath. They are from a few inches to about a foot in length, and vary in outline from ovate to oblong-lanceolate. In seedling plants the earliest fronds are round-cordate, the next cordate-ovate, and then follow trifoliate, pinnate, and finally mature bipinnate fronds. The largest fronds have about five pairs of compound pinnæ, each with from three to eleven pinnules, and above these are from four to six pairs of simple pinnæ, besides the terminal one, which is often the longest of all.

The pinnules and the simple pinnæ of the sterile fronds are commonly oval, and not more than half an inch long, but those of the fertile fronds are narrower and longer, sometimes nearly two inches long. The base is either truncate or slightly cordate; sometimes where there is a transition from compound to simple pinnæ, a pinna will be found conspicuously auricled on both sides, or on the upper side only. Forked pinnules are occasionally seen.

The margin is continuously recurved to form a rather broad involucre, and the very edge is somewhat thinner and whiter. The veins are pinnately arranged on both sides of the midvein, and fork about twice before reaching the margin. The upper part of the veinlets is covered with sporangia, which as they ripen push out from beneath the involucre. The spores are obscurely tetrahedral and trivittate, as in the other species of the genus.

This fern very often grows in company with _Camptosorus rhizophyllus_, and its root-stock is often hidden beneath mosses of the genus _Anomodon_: it takes kindly to cultivation, especially if it be planted in the crevices of calcareous rock-work. It may occur on other than calcareous rock, but I have never seen it on either granite, sandstone or basalt.

Names for varieties of this species have been proposed by Pursh, and by Fournier, but the characters assigned do not seem sufficiently distinctive.

PELLÆA GRACILIS, Hooker.
Slender Cliff-Brake.

Pellæa gracilis:—Root-stock slender, creeping, cord-like, scantily furnished with little ovate appressed scales; stalks scattered, slender, a span long or less, brownish-stramineous, somewhat shining, darker and slightly chaffy at the base; fronds two to four inches long, thin and tender, smooth, ovate or ovate-oblong, pinnate; pinnæ few, the lower two to four pairs once or twice pinnatifid, the uppermost simple; segments of the sterile fronds adnate-decurrent, roundish-obovate, crenately lobed and toothed; those of the taller fertile fronds lanceolate or linear-oblong, and more distinct, entire or auricled, terminal ones longest; veins rather distant, mostly once forked; involucre broad and continuous, delicately membranaceous.

_Pellæa gracilis_, Hooker, Sp. Fil., ii., p. 138, t. cxxxiii, B.—Eaton,
in Gray’s Manual, ed. v., p. 659; Ferns of the South-West, p.
319.—Hooker & Baker, Syn. Fil., p. 145.—Porter & Coulter, Syn. Fl.
Colorado, p. 153.

_Pteris gracilis_, Michaux, Fl. Bor.-Am., ii., p. 262.—Swartz, Syn. Fil.,
p. 99.—Willdenow, Sp. Pl., v., p. 376.—Pursh, Fl. Am. Sept., ii.,
p. 668.—Hooker, Fl. Bor.-Am., ii., p. 264.

_Allosorus gracilis_, Presl, Tent. Pterid., p. 153.—Torrey, Fl. New York,
ii., p. 486.—Gray, Manual, ed. i., p. 624; ed. ii., p. 591, t.
ix.—Parry, in Owen’s Geol. Surv. of Wisconsin, etc., p.
621.—Mettenius, Fil. Hort. Lips., p. 44.

_Cheilanthes gracilis_, Kaulfuss, Enum. Fil., p. 209.

_Pteris Stelleri_, Gmelin, “Nov. Com. Petrop., xii., p. 519, t. 12, f.
1.”

_Allosorus Stelleri_, Ruprecht, Distr. Crypt. Vasc. in Imp. Ross., p.
47.—Ledebour, Fl. Ross., iv., p. 526.—Moore, Ind. Fil., p.
46.—Lawson, in Canad. Naturalist, i., p. 272.

_Allosorus minutus & Pteris minuta_, Turczaninow, _fide_ Moore.

Hab.—Crevices of damp and shaded calcareous rocks, especially in deep
glens; Labrador, Butler, to British Columbia, and southward to Iowa,
Parry, Wisconsin and Pennsylvania. Also in Colorado, near Breckinridge
City, Brandegee. Siberia, Tibet and the Himalayas. It is found in
Sunderland, Massachusetts; at Trenton Falls, Chittenango Falls, and
other deep glens in Central New York; in Lycoming and Sullivan
Counties, Pennsylvania, and in other similar places in Vermont,
Michigan, etc., but is by no means a common plant.

Description:—This is the most delicate of all the _Pellæas_, and has fronds a good deal like those of _Cryptogramme acrostichoides_, but tenderer, and with sub-marginal fructification. The root-stock is very slender, scarcely more than half a line in thickness, and sometimes two or three inches long. It is so hidden in the crevices of the rocks that it is seldom secured by collectors. The scales are minute, appressed to the root-stock, and almost filmy in their delicacy.

The stalks are scattered along the root-stock, and are generally about five or six inches long, those of the fertile fronds longer, stouter and of a darker color than the others. They are smooth and somewhat polished, but lighter in color and far more tender in consistency than in most of our other species of this genus.

The fertile and the sterile fronds are unlike, though both are very delicately membranaceous, and pinnate with once or twice pinnatifid pinnæ. The rachis is not winged in its lower half, except in very small fronds, but above the middle it is narrowly winged, as are also its divisions. The lowest one or two pairs of pinnæ are twice pinnatifid in the largest specimens, but more commonly but once pinnatifid. In the sterile fronds the segments of the pinnæ are very plainly adnate to the secondary midrib, and are roundish or roundish-obovate in shape. They are from three to six lines long and about two-thirds as broad. Their margin is more or less lobed and crenately toothed. In the fertile fronds the segments are more distinct, longer and narrower, measuring often six to ten lines in length and one or two in width. The terminal pinna of the frond and the terminal segments of the pinnæ are considerably longer than the others. The veins are conspicuous, and distant, much more so than in our other species of _Pellæa_. They fork once about midway between the midvein and the margin, and sometimes, especially in fertile fronds, a second time just within the margin.

The involucre is continuous, broad, and even more delicate than the frond itself. The sporangia are comparatively scanty, and are fully covered by the involucre. The spores are spheroid-tetrahedral and obscurely trivittate.

Mr. Moore and some other authors are disposed to insist on the right of priority belonging to the specific name _Stelleri_. But the name _gracilis_ has been used by nearly every writer on American Ferns since the time of Michaux, and will most probably be kept up rather than the other.

It should be noted that Ruprecht considered his _Allosorus Stelleri_ to be distinct from our plant, and mentions several points of difference in his work on the Distribution of Vascular Cryptogamia in the Russian Empire.

The figure is taken from specimens collected in Sunderland, Hampshire
County, Massachusetts, by the late Rev. David Peck.

EVERGREEN WOOD-FERN.

ASPIDIUM MARGINALE, Swartz.
Evergreen Wood-Fern.

Aspidium marginale:—Root-stock ascending, stout, shaggy with long shining-brown chaffy scales; stalks rather stout, a few inches to a foot long, more or less chaffy with shining scales; fronds standing in a crown, one to two feet long, evergreen, sub-coriaceous, ovate-lanceolate, scarcely narrowed at the base, pinnate or sub-bipinnate; pinnæ almost sessile, the lowest ones broadest, unequally triangular-lanceolate, the middle ones lanceolate-acuminate, slightly broader above the base; pinnules or segments smooth and dark-bluish-green above, paler and sometimes slightly chaffy beneath, adnate to the narrowly winged secondary rachis, oblong or oblong-lanceolate, often sub-falcate, varying from crenately-toothed to pinnately-lobed with crenulate lobes, obtuse or sub-acute, those next the main rachis sometimes distinct, short-stalked, sub-cordate at the base and with rounded auricles; veins free, forked or pinnately branched into from two to five curved and usually conspicuous veinlets; sori rather large, placed close to the margin of the segments; the orbicular-reniform indusia firm in texture, convex, smooth, often lead colored.

_Aspidium marginale_, Swartz, Syn. Fil., p. 50.—Schkuhr, Krypt. Gew., p.
195, t. 45, _b._—Willdenow, Sp. Pl., v., p. 259.—Pursh, Fl. Am.
Sept., ii., p. 662.—Link, Fil. Hort. Berol., p. 107.—Hooker, Fl.
Bor.-Am., ii., p. 160.—Torrey, Fl. New York, ii., p. 495.—Gray,
Manual, ed. ii., p. 598.—Mettenius, Fil. Hort. Lips., p. 92;
Aspidium, p. 55.—Eaton, in Chapman’s Flora, p. 595.—Robinson, Ferns
of Essex Co., in Bull. Essex Inst., vii., No. 3, p. 50.—Williamson,
Ferns of Kentucky, p. 97, t. xxxv.—Davenport, Catal., p. 32.

_Polypodium marginale_, Linnæus, Sp. Pl., p. 1552.

_Nephrodium marginale_, Michaux, Fl. Bor.-Am., ii., p. 267.—Hooker, Sp.
Fil., iv., p. 122.—Hooker & Baker, Syn. Fil., p. 273.

_Lastrea marginalis_, Presl, Tent. Pterid., p. 77.—J. Smith, Ferns, Brit.
and Foreign, p. 157.—Lawson, in Canad. Naturalist, i., p. 281.

_Dryopteris marginalis_, Gray, Manual, ed. i., p. 632.—Darlington, Fl.
Cestrica, ed. iii., p. 396.

Hab.—Rocky hill-sides in rich woods, especially where black leaf-mold
has gathered between masses of rock; one of our most abundant and
characteristic ferns, confined to North America, but extending from New
Brunswick to Central Alabama, Professor Eugene A. Smith; westward to
Arkansas, Professor F. L. Harvey; Wisconsin, Parry, T. J. Hale; and
brought from the Saskatchewan and the Rocky Mountains of British
America by Drummond.

Description:—Professor Robinson has remarked of this species:—“This comes nearer being a tree fern than any other of our species; the caudex, covered by the bases of fronds of previous seasons, sometimes resting on bare rocks for four or five inches without roots or fronds.” The root-stock is much like that of _A. Filix-mas_, being very stout-closely covered with persistent stalk-bases and very chaffy. The chaff really grows mainly on the bases of the stalks, or covers the closely coiled buds which crown the root-stock. It is composed of shining ferruginous-brown thin lanceolate acuminate scales fully an inch in length, and destitute of a thickened midnerve. The fronds grow in elegant crowns from the apex of the root-stock, some six or eight or perhaps ten to a plant. The stalks vary in length, but are seldom more than a foot long. They are rather stout, round, but with a slight furrow in front, commonly reddish-brown in color, fading when dry to straw-color, and contain five or seven roundish fibro-vascular bundles, of which the two anterior ones are largest, and the next two the smallest.

The outline of the fronds is ovate-lanceolate, varying to oblong-lanceolate. The frond is commonly not quite so wide at the base as in the middle, though in small specimens the base is often the widest. The texture is thicker than in any other of our Wood-ferns, and the fronds are fairly evergreen, not withering until the next year’s fronds begin to uncoil. In cutting, the fronds vary from pinnate, with pinnatifid pinnæ and short nearly entire lobes, to twice pinnate, with pinnately-lobed segments. In the example selected for our plate the pinnules are oblong, obtuse and crenulate, or at most, crenately-toothed. Other, and perhaps no larger, fronds will have most of the pinnules twice or even thrice as long as these, ovate-lanceolate and pointed, narrowed to a sub-cordate and obscurely-stalked base, and deeply pinnately-lobed. This is var. _elegans_ of Professor Robinson. Professor Lawson has a var. _Traillæ_, which has “very large bipinnate fronds, all the pinnules pinnatifid.” A very common form noticed by Mr. L. M. Underwood in Bulletin of the Torrey Botanical Club, has fronds only four or five inches long, the lower pinnæ only pinnatifid and the upper ones lobed, the sori mostly solitary on the lobes.

The veins and veinlets of the frond are very distinct, being marked by depressions in the upper surface in the living fronds, and visible as dark lines in the dried specimens. The veins fork near the midvein; the upper branch may be fertile at its tip; the lower branch is either simple, or forks a second, and perhaps a third time. All the veinlets are curved. On account of the venation Presl referred this plant to his section _Arthrobotrys_.

The sori are close to the margin of the lobes, and vary from one to twelve to a lobe. They are very large and prominent, and have firm lead-colored orbicular-reniform indusia, which are slightly incurved round the edge, and depressed at the sinus. As the fronds mature the indusia become brownish. The spores are ovoid-reniform and have a narrow crenulate wing.

WALKING-LEAF.
PINNATIFID SPLEENWORT.

CAMPTOSORUS RHIZOPHYLLUS, Link.
Walking-Leaf.

Camptosorus rhizophyllus:—Root-stock short, creeping or ascending; stalks tufted, slender, flaccid, green, but becoming brown near the base; fronds a few inches to a foot long, sub-coriaceous, evergreen, smooth, gradually narrowed from a deeply cordate and auricled base to a long and very slender prolongation, decumbent and often rooting at the end; veins reticulated near the midrib, and having free apices along the margin; sori elongated, variously placed on either side of the veins, often face to face in pairs, or extending around the upper part of the meshes; indusium delicate.

_Camptosorus rhizophyllus_, Link, Hort. Berol., ii., p. 69; Fil. Sp.
Hort. Berol., p. 83.—Presl, Tent. Pterid., p. 121, t. 4, fig.
8.—Hooker, Gen. Fil., t. 57, C; Fil. Exot., t. 85.—Gray,
Manual.—Darlington, Flora Cestr., ed. iii., p. 393.—Mettenius, Fil.
Hort. Lips., p. 67, t. 5, fig. 6.

_Asplenium rhizophyllum_, Linnæus, Sp. Pl., p. 1536.—Swartz, Syn. Fil.,
p. 74.—Willdenow, Sp. Pl., v., p. 305.—Michaux, Fl. Bor. Am., ii.,
p. 264.—Bigelow, Fl. Boston.

_Antigramma rhizophylla_, J. Smith, in Hook. Journ. Bot., iv., p. 176;
Ferns, British and Foreign, p. 226.—Torrey, Fl. New York, ii., p.
494, t. 159 (_Asplenium_).

_Scolopendrium rhizophyllum_, Endlicher, Gen. Pl., Suppl. i., p.
1348.—Hooker, Sp. Fil., iv., p. 4.—Hooker & Baker, Syn. Fil., p.
248.

Hab.—On mossy rocks, especially limestone. Not uncommon from Canada to
Virginia and Alabama, and westward to Wisconsin and Kansas. It occurs
in many places in Western New England, but is rare to the east. It has
lately been found a few miles from Boston; but there is a doubt whether
the station is truly natural.

Description.—The walking-leaf is usually found in patches of considerable extent. It seems to prefer mossy calcareous rocks, and the finest specimens are usually firmly rooted in the crevices. In Cheshire, Connecticut, it grows freely on moist cliffs of sandstone bordering a deep ravine; and in Orange, in the same State, it is found on scattered ledges of serpentine. The root-stock is very short, but creeping: it bears a few dark-fuscous scales, and is covered with the remains of decayed stalks. A few fronds grow from the end of the root-stock, and are supported on slender herbaceous stems a few inches long. A transverse section of the lower part of the stalk is semicircular, and shows a very slender triangular central thread of dark sclerenchyma, with two somewhat roundish fibro-vascular bundles close beneath or behind it. A section higher up shows that the stalk is there narrowly winged on each side, and the two fibro-vascular bundles have coalesced into one of a roundish-triangular shape. The frond is long and narrow, and rarely rises erect, but usually is decumbent or reclined in position.

The wings of the stalk widen out into a wedge-shaped base, which is sunken in a sinus between two basal auricles of the frond. These auricles are scantily developed in small fronds; but in larger ones they are more or less prominent, making the base of the frond either cordate or hastate. In specimens from Cheshire, Connecticut, and in some from Indiana, the auricles are drawn out into slender points, in one instance fully four inches long. The fronds are deep-green in color, and sub-coriaceous in texture. The fronds of mature plants are from six to twelve, or even fifteen, inches long; and their greatest width, measured just above the auricles, is about one-twelfth of the length, or from six to fifteen lines. The midrib is a little paler than the rest of the frond, and is rather prominent on the under surface. The margin of the frond is gently undulating or entire, rarely incised.[2] The upper part of the frond is scarcely wider than the stalk, and commonly produces a proliferous bud at the apex, where it very frequently takes root, and develops a new plant. In this way a single plant in a favorable position will become a whole colony in a few years’ time.

The venation is peculiar, and the disposition of the sori depends mainly on the peculiarities of the venation. Dr. Endlicher’s description of them is so clear, that it is well to repeat it here: “Veins anastomosing [i.e., reticulating] in two series of hexagonal areoles [meshes], the angles of the marginal areoles sending out free, simple or forked, veinlets. Sori linear, solitary in the costal areoles [those nearest the midrib] and on the marginal veinlets: the indusium of the latter free toward the margin of the frond; of the former, toward the costa. In the areoles of the second series the sori are opposite: the indusium of the lower one free toward the costa; of the other, in the opposite direction.” To this it may be added, that in some of the areoles the two sori meet and are confluent at the outer angle of the areole; and in this case the two indusia are sometimes, though not always, united into one. The indusia of the areoles next the midrib are also often bent at an angle, and the two portions plainly united. It was from this condition of some of the sori that the genus was named _Camptosorus_ (bent fruit-dot); and it is only on this peculiarity that the genus can be kept separate.

The indusium is thin and delicate, composed of sinuous-margined cellules, and is more or less wavy along the free edge. The spores are ovoid, and have a crenated pellucid wing-like margin.

Sir W. J. Hooker referred the _Camptosorus_, together with the species of _Antigramma_, and the very peculiar Mexican fern _Schaffneria_, to the genus _Scolopendrium_; making the distinctive character of the genus to rest on the sori being “in pairs, opposite to each other, one originating on the superior side of a veinlet, the other on the inferior side of the opposite veinlet or branch.” In this he was essentially anticipated twenty years by Dr. Endlicher; to whom, however, _Schaffneria_ was unknown.

It is by no means impossible that future botanists will refer all these species to the old Linnæan genus _Asplenium_; for it is now pretty generally admitted that differences in venation do not constitute valid generic distinctions, and a radicant bud on the frond is common in many undeniably genuine _Asplenia_: and since _Diplazium_, with double involucres placed back to back on the same vein, is inseparable from _Asplenium_, it is by no means impossible that _Scolopendrium_ and _Camptosorus_ should be thought to have no better claim to rank as genera.

Probably the earliest notice of the walking-leaf is in Ray’s “Historia Plantarum,” vol. ii., p. 1927, published in 1688. It is there called “Phyllitis parva saxatilis per summitates folii prolifera.” Other early accounts may be found in the “Species Plantarum” of Linnæus and of Willdenow, and in the second edition of Gronovius’s “Flora Virginica.” In the latter work it may be seen that Gov. Colden long ago described the auricles as being “also often acuminate.”

A second species, with membranaceous fronds acute at the base (C. Sibiricus), occurs in Northern Asia, but is apparently very rare.

ASPLENIUM PINNATIFIDUM, Nuttall.
Pinnatifid Spleenwort.

Asplenium pinnatifidum:—Root-stock short, creeping, branched; stalks numerous, clustered, brownish near the base, green higher up; fronds six to nine inches high, herbaceous or sub-coriaceous, mostly erect, lanceolate-acuminate from a broad and sub-hastate base, pinnatifid; lower lobes roundish-ovate or rarely caudate, sometimes distinct, the margin crenated, the upper ones gradually smaller and more and more adnate to the winged midrib; the uppermost very short, and passing into the sinuous-margined long acumination of the frond; veins dichotomous or sub-pinnate and forking, free; sori few on the lower lobes, solitary on the uppermost, those next the midrib occasionally diplazioid.

_Asplenium pinnatifidum_, Nuttall, Genera of N. Amer. Plants, ii., p.
251.—Kunze, in Sill. Journ., July, 1848, p. 85.—Gray,
Manual.—Eaton, in Chapman’s Flora of Southern U. S., p.
592.—Hooker, Icones Plantarum, t. 927; Sp. Fil., iii., p.
91.—Mettenius, Fil. Hort. Lips., p. 72, t. 10, figs. 1, 2;
Asplenium, p. 126.—Hooker & Baker, Syn. Fil., p. 194.

_Asplenium rhizophyllum_, var. _pinnatifidum_, Muhlenberg, Catalogus
Plant. Am. Sept., ed. ii., p. 102.—Barton, Compendium Floræ
Philad., ii., p. 210.—Eaton,[3] Manual of Botany, ed. iii., p. 188,
etc.—Torrey, Compendium, p. 383.

Hab.—Discovered by Thomas Nuttall in crevices of rocks along the
Schuylkill River, near Philadelphia; also found along the Wissahickon
Creek in the same vicinity. Lancaster County, Pennsylvania, Prof.
Thomas C. Porter. On moist cliffs of sandstone in the Cumberland
Mountains, East Tennessee, Prof. F. H. Bradley. Hancock County,
Alabama, Hon. T. M. Peters. Mine-la-Motte, Southern Missouri, on
sandstone rocks, Dr. Engelmann.

Description.—The root-stocks of this little fern are creeping, branched and often entangled, and chaffy with narrow lance-acuminate dark-fuscous scales. The cellular structure of these scales is similar to that of the scales of _A. ebeneum_, the cells being oblong-rectangular, and arranged in straight longitudinal rows. The stalks are from two to four inches long, and slightly chaffy when young: they are brown and shining at the base, but green higher up, except that a narrow line of brown is continued up the under side of the stalk nearly or quite to the base of the frond. A section made near the lower extremity of the stalk is nearly semicircular, and discloses two roundish fibro-vascular bundles side by side near the middle, and a minute thread of sclerenchyma, or hard dark tissue, on the inner side of each bundle. A section just below the frond shows the two fibro-vascular bundles united into one, and the angles of the stalk slightly extended, forming very narrow wing-like borders. The minute inner filaments of sclerenchyma are never continued far up the stalk, and are sometimes wanting altogether.

The frond is from three to six inches long, and usually half an inch to an inch broad at the base, from which the general outline tapers to a long and slender point, not so long as the prolongation of the walking-leaf, and very rarely, if ever, rooting at the apex.[4] The fronds are mostly erect, sub-coriaceous or firmly membranaceous, smooth above, but with a few minute setulose scales beneath, deeply pinnatifid in the lower and middle portion, and sinuately lobed above, the long terminal portion undulate on the margins. The midrib is broad and well defined: it is winged throughout its length; the wing narrow at the base of the frond, but constantly widening upwards.

The lobes are irregularly roundish-ovate, sinuate, crenate or slightly toothed; the lowest ones occasionally drawn out into an acuminate point an inch long. Most of the lobes are attached to the wing of the midrib by a broad base: the lower ones sometimes have a short stalk.

The veins are everywhere free: in the lower lobes, if these are acuminate, the veins are pinnately branched from a mid-vein; elsewhere they are forked or dichotomous. The sori are mostly single, though here and there one will be diplazioid,—most commonly the lowest one on the superior side of the lobe. The indusia are very delicate; and the free edge is directed toward the middle of the lobe, excepting the indusia of the sori nearest the midrib, and these open toward the midrib. The sori are usually very full of sporangia, and, when ripe, nearly cover the back of the frond: even the narrow acumination bears a sorus at each undulation of the margin. Spores ovoid-bean-shaped, with reticulating ridges and an irregular winged border.

This is now admitted by all pteridologists to be a distinct species; though it was formerly confounded with the _Camptosorus_, from which it is clearly distinguished by the free veins, the mostly single indusia, and the usual absence of a proliferous bud at the apex of the frond. Some of the less compound and more attenuated forms of _A. montanum_ come much nearer to it; but in its simplest form this other species always has the fronds fairly pinnate, and its more compound forms resemble the _A. pinnatifidum_ very little.

I take occasion to express my thanks to Hon. Thomas M. Peters of Moulton, Alabama, who has sent me abundant and fine specimens of this fern and of other rare species which are found in the northern part of Alabama.

SENSITIVE FERN.

ONOCLEA SENSIBILIS, Linnæus.
Sensitive Fern.

Onoclea sensibilis:—Root-stock creeping, elongated; stalks scattered, nearly chaffless, a few inches to over a foot high; fronds dimorphous; sterile ones triangular-ovate, foliaceous, smooth, quickly withering when plucked, deeply pinnatifid into several oblong-lanceolate entire or sinuate or sinuately pinnatifid segments, the lowest pair sometimes distinct, the rest connected by a wing which widens upwards; the veins reticulated and forming narrow paracostal areoles, and, outside of these, copious oblong or hexagonal meshes; fertile fronds shorter, contracted, rigid, closely bipinnate; the pinnules rolled up into berry-like bodies; veins free, simple or forked, soriferous on the back; sporangia borne on an elevated receptacle, half surrounded by a very delicate somewhat hood-like indusium attached at the base of the receptacle.

_Onoclea sensibilis_, Linnæus, Sp. Pl., p. 1517.—Michaux, Fl. Bor.-Am.,
ii., p. 272.—Swartz, Syn. Fil., p. 110.—Schkuhr, Krypt. Gew., p.
95, t. 102.—Willdenow, Sp. Pl., v., p. 287.—Pursh, Fl. Am. Sept.,
ii., p. 665.—Hooker, Gen. Fil., t. lxxxii; Fl. Bor.-Am., ii., p.
262; Sp. Fil., iii., p. 160.—Torrey, Fl. New York, ii., p.
499.—Gray, Manual, ed. i., p. 457; ed. ii., p. 599, t. xii; ed. v.,
p. 668, t. xviii; Botany of Japan, in Mem. Amer. Acad. (n. s.) vi.,
p. 421.—Mettenius, Fil. Hort. Lips., p. 97.—Maximowicz, Prim. Fl.
Amur., p. 337.—Eaton, in Chapman’s Flora, p. 596.—Hooker & Baker,
Syn. Fil., p. 46.—Miquel, Prolus. Fl. Jap., in Ann. Mus. Bot.
Lugd.-Batav., iii., p. 179.—Milde, Fil. Eur. et Atlant., p.
157.—Redfield, in Bulletin of Torrey Botan. Club, vi., p.
4.—Williamson, Ferns of Kentucky, p. 109, t. xli; Fern-Etchings, t.
xlv.

_Onoclea obtusilobata_, Schkuhr, Krypt. Gew., p. 95, t. 103.—Pursh, Fl.
Am. Sept., ii., p. 665.

_Onoclea obtusiloba_, Link, Fil. Hort. Lips., p. 37.

_Osmunda frondibus pinnatis foliolis superioribus basi coadunatis,
omnibus lanceolatis, pinnato-sinuatis_, Linnæus, Hort. Cliff., p.
472.—Gronovius, Fl. Virginica, p. 196; ed. ii., p, 163.—(Other
ancient names are repeated by Linnæus and Willdenow.)

Hab.—Wet meadows and thickets, from New Brunswick to the Saskatchewan,
extending southward through Dacotah, Kansas, and Arkansas to Louisiana,
and eastward to St. Augustine, Florida, one of our commonest and most
abundant ferns, often occupying large portions of land to the partial
exclusion of other plants. Not found in western America or in Europe,
but occurring in Japan, Mantchooria and eastern Siberia.

Description:—The root-stock is about one-third of an inch thick, and irregularly roundish in section. It creeps widely below the surface of the ground, rooting freely and often forking, so that in cultivation it is very difficult to confine the plant to one spot. The root-stock contains six or eight roundish or flattened fibro-vascular bundles arranged in a circle near the outer surface. It bears no chaff. The stalks are scattered along its length, the apex being covered with the thickened stalk-bases of next year’s fronds, and the stalks for the present year rising a few inches back of the apex.

The fronds are truly dimorphous, the fertile ones being so unlike the sterile, that no one who is unacquainted with the plant would suppose they had anything to do with each other.

The sterile fronds vary in length from one or two inches to fifteen or eighteen, and are supported on stalks usually rather longer still, so that, while the smallest plants may be concealed in the grass, the tallest ones are often fully three feet high. The bases of the stalks are flattened, discolored and very sparingly chaffy; the upper part is green in the living plant, brownish-stramineous when dried, smooth and naked, rounded at the back, and slightly furrowed in front. It contains two obliquely-placed strap-shaped fibro-vascular bundles, which unite below the base of the frond and form one having a U-shaped section. The outline of the sterile fronds is triangular or triangular-ovate. The midrib is winged, either from the very base, or from the second pair of segments; the wing at its lower extremity very narrow, but gradually widening towards the apex, so that its greatest width is but little less than that of the terminal segment. The number of segments in the smallest fronds is two or three on each side; in the largest fronds twelve or thirteen on each side. The lowest segments are rather more than half as long as the whole frond; the next segments usually a little smaller, but sometimes a little longer than the first pair, and the remaining ones rapidly decreasing. The segments are broadly lanceolate or oblong-lanceolate, narrowed at the base, especially the lower ones, and either rounded or sub-acute at the apex. The sinuses between them are rounded, and are gradually narrowed towards the apex of the frond. The segments are very minutely serrulate on the edges; the smallest ones otherwise entire, and the larger ones either with sinuous margins or, in large fronds, deeply sinuous-pinnatifid. The texture is herbaceous, the surfaces perfectly smooth, the color of the upper surface grass-green, of the lower surface paler and slightly glaucescent. The fronds wilt very soon after plucking them, and in wilting there is a slight disposition to fold the segments together, face to face, for which reason the plant has received the name of “Sensitive-Fern.” The first frost of autumn destroys the sterile fronds; and a late frost in May or June does the same. The midribs are prominent, and the veins conspicuous; the latter being copiously reticulated into areoles which enclose no free veinlets. Along the sides of the midribs and midveins are very long and narrow areoles, and outside of these are obliquely-placed oblong areoles in several irregular rows.

The fertile fronds are not very common, and a young botanist may search in vain for them for a long time. They stand only about half as high as the sterile fronds, and are very rigid. They are nearly black in color: in winter they dry up, but remain erect through the next summer, so that a fruiting plant often has fertile fronds standing of two years’ growth. The frond is only a few (usually four to six) inches long, and consists of from four to ten pairs of appressed fleshy or cartilaginous pinnæ, which are divided into a double row of sub-globose bead-like segments or pinnules; the whole looking like a small and narrow but dense cluster of diminutive grapes. Each pinnule has its edges so much recurved that the whole forms a sort of pouch, apparently filled with sporangia.

Mr. Faxon has made a careful study of the sori, and has very kindly furnished the account given below.[5]

The articulations of the sporangia are said by Fée to be twenty-eight to thirty-two, and more numerous than in any other fern. I have counted only thirty at most, and more frequently only twenty-eight. The spores are ovoid and very dark-colored.

Var. _obtusilobata_, Torrey, Fl. New York, ii., p. 499, t. clx (_Onoclea obtusilobata_, Schkuhr), is not a permanent variation of the species, but is based on a not infrequent condition of the plant, in which the pinnæ of some of the foliaceous fronds become deeply pinnatifid into obovate segments, which have mostly free veins and imperfectly developed sori. The indusia appear as little whitish scales on the back of the veins. It occurs in almost all places where the plant is common, is often produced from root-stocks which bear also normal fronds, and presents all gradations from the usual sterile frond to the proper fertile one. _Ragiopteris onocleoides_ of Presl is founded on a young fertile frond of this species placed with a sterile one of what Milde judges to be a monstrous form of _Aspidium Filix-mas_. Maximowicz describes a var. _interrupta_, from the Amoor region, in which the fertile frond nearly equals the sterile, and has elongated pinnæ, with remote segments. This condition is also sometimes seen in American specimens, and is hardly a true variety.

In an article on “The late Extinct Floras of North America,” which appeared in Vol. ix of the Annals of the New York Lyceum of Natural History, in April, 1868, Professor Newberry describes certain fossil specimens of ferns occurring in Miocene argillaceous limestone at Fort Union, Dacotah, and refers them with little hesitation to this species. I have not seen the specimens, but, as similar venation and not very dissimilar fronds are seen in Woodwardia and Pteris, one may perhaps doubt the absolute certainty of the identification.

Footnotes

[1]Milde indicates several other unimportant variations; and Hooker &
Baker have as varieties of this species the East Indian _Aspidium
cochleatum_, and _Aspidium elongatum_, from Madeira and the Canary
Islands. The latter they give as occurring also in the southern
United States, evidently supposing it to be the long-lost _A.
Ludovicianum_ of Kunze. For abundant synonymy of _Aspidium Filix-mas_
the student is referred especially to the works of Hooker, Milde,
Mettenius and Moore, as quoted above.

[2]See the “Flora of New York” for some figures of laciniated and forking
fronds.

[3]Prof. Amos Eaton, grandfather of the present writer. Eaton’s “Manual
of Botany” went through eight editions from 1817 to 1841.

[4]I find one or two instances of a slight enlargement of the apex, as if
there were an attempt to form a proliferous bud.

[5]“In _O. sensibilis_ the sori are borne on the middle of the vein, and
consist of a tough cylindrical receptacle, three or four diameters in
height, bearing sporangia thickly all over its surface, and covered
when young by a delicate hood-like indusium, attached half-way or
more around the base of the receptacle on the inferior side, and
having the crenulate-margined opening toward the apex of the segment.
At an early stage the blackberry-shaped sorus is almost entirely
covered by the indusium, which resembles a closely drawn cowl, but
with the growth of the sporangia it is thrown back, or rent, and soon
disappears, the sori becoming confluent. The receptacle is very
persistent, and may be seen, covered with the stalks of the
sporangia, in the dried last-year’s fertile fronds, which are always
found where the plant grows.”

Transcriber’s Notes

--Copyright notice provided as in the original—this e-text is public
domain in the country of publication.

--Silently corrected palpable typos; left non-standard spellings and
dialect unchanged.

--Only in the text versions, delimited italicized text in _underscores_
(the HTML version reproduces the font form of the printed book.)

--Only in the ASCII text version, delimited translated Greek letters in
{braces} (the UTF text and HTML versions preserve the Greek letters.)