7. A. Bradleyi, D. C. Eaton. _Fronds oblong-lanceolate_, 4--7' long, besides the blackish and somewhat shining stipe, membranaceous, pinnate; pinnae rather numerous, _the lower ones no larger than the middle ones_, all short-stalked, oblong-ovate, obtuse, incised or pinnatifid into oblong toothed lobes.--On rocks, Ky. and southward; rare. A single plant has been gathered near Newburg, N. Y.--Intermediate between A. ebeneum and A. montanum.

8. A. montanum, Willd. _Fronds ovate-lanceolate from a broad base_ (2--5' long), subcoriaceous, pinnate; pinnae ovate-oblong, the lowest pinnately cleft into oblong or ovate cut-toothed lobes, the upper gradually simpler; _rhachis green, broad and flat; stipe brown at base_.--Cliffs and rocks, from Conn. and Penn. to Ky., and southward.

July.

9. A. Ruta-muraria, L. _Fronds deltoid-ovate_ (1--2' long), subcoriaceous, laxly 2--3-pinnate at base, the pinnae alternate; _ultimate segments few_, stalked (2--5" long), _from narrowly cuneate to roundish-obovate_, toothed or incised at the apex; veins forking; sori 2--4 on a segment.--Limestone cliffs, Vt. to Mich., and southward; scarce. July. (Eu.)

[*][*][*][*] _Tall ferns (2--4 high), not evergreen; fronds pinnate or sub-bipinnate._

10. A. angustiflium, Michx. _Fronds_ thin, _simply pinnate; pinnae_ numerous, short-stalked, _linear-lanceolate, ac.u.minate_, entire or crenulate (3--4' long), _those of the fertile frond narrower_; fruit-dots linear, 20--40 each side of the midvein; indusia slightly convex.--Rich woods, W. New Eng. to Wisc., and southward along the mountains. Sept.

11. A. thelypterodes, Michx. (Pl. 18, fig. 1, 2.) _Fronds_ (2--3 high) _pinnate; pinnae deeply pinnatifid_, linear-lanceolate (3--5' long); the lobes oblong, obtuse, minutely toothed, crowded, each bearing 3--6 pairs of _oblong fruit-dots_, some of them double.--Rich woods; not rare.

July--Sept.

-- 2. ATHRIUM. _Indusium delicate, curved, often crossing the vein, and attached to both sides of it, thus becoming reniform, or shaped like a horseshoe._

12. A. Filix-f'mina, Bernh. Fronds (1--3 high) ovate-oblong or broadly lanceolate, twice pinnate; pinnae lanceolate, numerous; pinnules confluent on the secondary rhachis by a narrow margin, oblong and doubly serrate, or elongated and pinnately incised with cut-toothed segments; fruit-dots short, variously curved, at length confluent.--Moist woods; common and presenting many varying forms. July. (Eu.)

10. SCOLOPeNDRIUM, Smith. HART'S-TONGUE. (Pl. 18.)

Fruit-dots linear, elongated, almost at right angles to the midrib, contiguous by twos, one on the upper side of one veinlet, and the next on the lower side of the next superior veinlet, thus appearing to have a double indusium opening along the middle. (The ancient Greek name, so called because the numerous parallel lines of fruit resemble the feet of the centipede, or _Scolopendra_.)

1. S. vulgare, Smith. Frond oblong-lanceolate from an auricled-heart-shaped base, entire or wavy-margined (7--18' long, 1--2'

wide), bright green.--Shaded ravines and under limestone cliffs; central N. Y.; also in Canada and Tenn.; very rare. Aug. (Eu.)

11. CAMPTOSRUS, Link. WALKING-LEAF. (Pl. 18.)

Fruit-dots oblong or linear, as in Asplenium, but irregularly scattered on either side of the _reticulated veins_ of the simple frond, those next the midrib single, the outer ones inclined to approximate in pairs (so that their two indusia open face to face), or to become confluent at their ends, thus forming crooked lines (whence the name, from ?apt??, _bent_, and s????, for _fruit-dot_.)

1. C. rhizophllus, Link. Fronds evergreen, sub-coriaceous, growing in tufts, spreading or proc.u.mbent (4--12' long), gradually narrowed from a cordate or auricled base to a long and slender ac.u.mination, which often roots at the end and forms a new plant.--Shaded rocks, especially calcareous rocks, N. Eng. to Minn., and southward to Kan. and Ala.--The auricles are sometimes greatly elongated, and even rooting; in another form they are lacking, as in the thinner leaved C. Sibiricus. July.

12. PHEGoPTERIS, Fee. BEECH FERN.

Fruit-dots small, round, naked (no indusium), borne on the back of the veins below the apex. Stipe continuous with the rootstock.--Our species have free veins and bright green membranaceous fronds, decaying in early autumn. (Name composed of f????, an _oak_ or _beech_, and pte???, _fern_.)

[*] _Fronds twice pinnatifid; pinnae all sessile, adnate to the winged rhachis._

1. P. polypodiodes, Fee. Fronds triangular, _longer than broad_ (4--9'

long), hairy on the veins, especially beneath; pinnae linear-lanceolate, _the lowest pair deflexed and standing forward_; their divisions oblong, obtuse, entire, the basal decurrent upon the main rhachis; fruit-dots all near the margin.--Damp woods; common northward. July.--Rootstock slender, creeping, bearing a few distant slender stalks, rather longer than the fronds. (Eu.)

2. P. hexagonoptera, Fee. Fronds triangular, _usually broader than long_ (7--12' broad), slightly p.u.b.escent and often finely glandular beneath; pinnae lanceolate; upper segments oblong, obtuse, toothed or entire, _those of the very large lowest pinnae elongated and pinnately lobed_, basal ones very much decurrent and forming a continuous many-angled wing along the main rhachis; fruit-dots near the margin; some also between the sinus and the midrib.--Rather open woods, New Eng. to Minn., and southward; common. July.--Larger and broader than the last, which it often closely resembles.

[*][*] _Fronds ternate, the three divisions petioled; rhachis wingless._

3. P. Dryopteris, Fee. _Fronds smooth_, broadly triangular (4--6' wide); the three triangular primary divisions _all widely spreading_, 1--2-pinnate; segments oblong, obtuse, entire or toothed; fruit-dots near the margin.--Rocky woods; common northward. July. (Eu.)

4. P. calcarea, Fee. _Fronds minutely glandular_ and somewhat rigid, _the lateral divisions ascending_; lowest inferior pinnae of the lateral divisions smaller in proportion than in the last species, which it otherwise closely resembles.--Iowa and Minn.; rare. July. (Eu.)

13. ASPiDIUM, Swartz. SHIELD FERN. WOOD FERN. (Pl. 19.)

Fruit-dots round, borne on the back or rarely at the apex of the veins.

Indusium covering the sporangia, flat or flattish, scarious, orbicular and peltate at the centre, or round-kidney-shaped and fixed either centrally or by the sinus, opening all round the margin. Stipe continuous (not articulated) with the rootstock.--Our species have free veins and 1--3-pinnate fronds. (Name, ?sp?d???, _a small shield_, from the shape of the indusium.)

-- 1. DRYoPTERIS. _Indusium reniform, or orbicular with a narrow sinus._

[*] _Veins simple or simply forked and straight; fronds annual, decaying in autumn, the stalks and slender creeping rootstocks nearly naked._

1. A. Thelpteris, Swartz. Fronds pinnate, lanceolate in outline; pinnae horizontal or slightly recurved, linear-lanceolate, deeply pinnatifid, _the lowest pairs scarcely smaller_; lobes oblong, entire, obtuse or appearing acute when in fruit from the _strongly revolute margins; veins mostly forked_, bearing the (soon confluent) fruit-dots near their middle; indusium minute, smooth and naked.--Marshes; common. Aug.--Stalk 1 long or more, usually longer than the frond, which is of thicker texture than the next, and slightly downy. (Eu.)

2. A. Noveboracense, Swartz. Fronds pinnate, lanceolate in outline, _tapering both ways from the middle_; pinnae lanceolate, _the lowest 2 or more pairs gradually shorter and deflexed_; lobes flat, oblong, basal ones often enlarged and incised; _veins simple_, or forked in the basal lobes; fruit-dots distinct, near the margin; indusium minute, the margin glanduliferous.--Swamps and moist thickets; common. July.--Frond pale green, delicate and membranaceous, hairy beneath along the midribs and veins.

[*][*] _Veins, at least the lowest, more than once forked or somewhat pinnately branching; fruit-bearing veinlets often obscure or vanishing above the fruit-dot; fronds, at least the sterile ones, often evergreen; stalks and apex of the thickened rootstock scaly or chaffy, and often the main rhachis also._

[+] _Fronds small, pinnate; pinnae pinnatifid; indusia very large, persistent._

3. A. fragrans, Swartz. Fronds (4--12' high) glandular and aromatic, narrowly lanceolate, with linear-oblong pinnately-parted pinnae; their crowded divisions (2" long) oblong, obtuse, toothed or nearly entire, nearly covered beneath with the very large thin imbricated indusia, which are orbicular with a narrow sinus, the margin sparingly glanduliferous and often ragged.--On rocks, especially near waterfalls, mountains of northern New Eng., west and northward.--Rootstock stout, nearly erect, densely chaffy, as are the crowded stipes and rhachis.

(Asia, and barely reaching S. E. Eu.)

[+][+] _Large (1--2 high), the fronds mostly twice pinnate with variously toothed and incised pinnules; indusia rather small, shrivelled in age, or deciduous._

4. A. spinulsum, Swartz. Stipes with a few _pale-brown deciduous scales_; frond ovate-lanceolate, twice pinnate; _pinnae oblique to the rhachis, elongated-triangular_, the lower pairs broadly triangular; pinnules set obliquely on the midribs, connected by a very narrow wing, oblong, acute, incisely serrate or pinnatifid with spinulosely-toothed lobes; _indusium_ smooth and _without marginal glands_.--In damp woods, New Eng. to Ky., and northward. July.--The common European type, rare in North America. (Eu.)

Var. intermedium, D. C. Eaton. _Scales_ of the stipe few, _brown with a darker centre_; frond broadly oblong-ovate, twice or often thrice pinnate; _pinnae spreading, oblong-lanceolate_, the lower unequally triangular-ovate; pinnules crowded, ovate-oblong, spreading, pinnately divided; the oblong lobes spinulose-toothed at the apex; _margin of the indusium denticulate and beset with minute stalked glands_.--Woods, everywhere.

Var. dilatatum, Hook. _Scales_ of the stipe large, _brown with a dark centre_; _frond broader, ovate or triangular-ovate_ in outline, oftenest thrice pinnate; pinnules lance-oblong, the lowest often much elongated; _indusium_ (in the North American plant) _smooth and naked_.--A dwarf state, fruiting when only 5--8' high, answers to var. dumetorum.--N. New Eng. to Minn., chiefly in mountain woods, and northward. (Eu.)

5. A. Bottii, Tuckerman. _Scales_ of the stipe _pale-brown_; fronds (1--2 long) elongated-lanceolate in outline, somewhat narrowed at base; lowest pinnae triangular-ovate, the upper longer and narrower; pinnules oblong-ovate, sharply spinulose-serrate or the lower pinnatifid; _indusium minutely glandular_. (A. spinulosum, var.

Boottii, of last ed. A. cristatum, var. uliginosum, _Milde_.)--Wet thickets and about ponds, New Eng. to Del. and Minn. July.--Sterile fronds much smaller and simpler than the fertile. (Eu.)

[+][+][+] _Large (2--4 high); fronds once pinnate and the pinnae deeply pinnatifid, or nearly twice pinnate; fruit-dots not very near the margin; the indusium large, thinnish and flat, persistent._

6. A. cristatum, Swartz. _Frond linear-oblong or lanceolate in outline_ (1--2 long); _pinnae short_ (2--3' long), _triangular-oblong_, or the lowest nearly triangular-ovate, from a somewhat heart-shaped base, acute, deeply pinnatifid; the _divisions (6--10 pairs) oblong_, very obtuse, finely serrate or cut-toothed, the lowest pinnatifid-lobed; _fruit-dots as near the midvein as the margin_; indusium round-reniform, the sinus mostly shallow, smooth and naked.--Swamps, etc.; common.

July.--Stipes and the stout creeping rootstock bearing broad and deciduous chaffy scales. (Eu.)

Var. Clintonianum. _Frond in every way much larger_ (2--4 long); _pinnae_ oblong-lanceolate, _broadest at base_ (4--6' long, 1--2' broad), deeply pinnatifid; the _divisions (8--16 pairs)_ crowded or distant, _linear-oblong_, obtuse, obscurely serrate or cut-toothed, the basal sometimes pinnately lobed; veins pinnately forking, the lowest anterior veinlets bearing the _fruit-dots near the midvein_; indusium orbicular with a shallow sinus, smooth and naked.--Swampy woods, New Eng. to N. J., N. Y. (_G. W. Clinton_, etc.), and westward. July.--Rootstock stout, creeping, chaffy (like the stipes) with large bright-brown scales. A showy fern, unlike any European form of A. cristatum, and often mistaken for A. Goldianum.

7. A. Goldianum, Hook. _Frond broadly ovate_, or the fertile ovate-oblong in outline (2--3 long); _pinnae_ (6--9' long), oblong-lanceolate, _broadest in the middle_, pinnately parted; the _divisions (about 20 pairs) oblong-linear, slightly scythe-shaped_ (9--15" long), serrate with appressed teeth; veins pinnately forking and bearing the _fruit-dots very near the midvein_; indusium very large, orbicular with a deep narrow sinus, smooth and without marginal glands.--Rich and moist woods, from Conn. to Ky., and northward.

July.--A stately fern, often 4 high, the fronds growing in a circle from a stout ascending chaffy rootstock, and decaying in autumn.

Indusium with the sides of the sinus often overlapping, thus appearing to be round and entire as in -- Polystichum.

[+][+][+][+] _Large (1--3 high); stipes very chaffy at base; fronds twice pinnate, but the upper pinnules confluent, some of the lower pinnatifid-toothed; fruit-dots rather large; indusium convex, without marginal glands, persistent._

8. A. Filix-mas, Swartz. Frond lanceolate in outline (1--3 high); pinnae linear-lanceolate, tapering from base to apex; pinnules oblong, very obtuse, serrate at the apex and obscurely so at the sides, the basal incisely lobed, distinct, the upper confluent; fruit-dots nearer the midvein than the margin, and usually confined to the lower half of each fertile pinnule.--Rocky woods, N. Mich. to Dak. and Col.--Frond thickish but not surviving the winter. (Eu.)

9. A. marginale, Swartz. (Pl. 19, fig. 1, 2.) Frond evergreen, smooth, thickish and almost coriaceous, ovate-oblong in outline (1--2 long); pinnae lanceolate, ac.u.minate, slightly broadest above the base; pinnules oblong or oblong-scythe-shaped, crowded, obtuse or pointed, entire or crenately-toothed; fruit-dots close to the margin.--Rocky hillsides in rich woods; common, especially northward. Aug.