Chapter L: ALPINUM, L., or its var. SABINAEFOLIUM, occurs from Labrador to (2)

1. H. scutatus, Spruce. Stems filiform, decumbent, usually simple; leaves smaller at the base and apex of the stems, roundish-ovate, concave, sharply bidentate, the apex lunate or acute; underleaves large, acuminate, involucral leaves two, 2--3-cleft, the upper adnate to the perianth; perianth ovate, becoming obovate, obscurely 3--4-plicate, splitting above on one side; capsule deep brown. (Jungermannia scutata, _Weber._)--On rotten logs in damp places; common. (Eu.)

H. FLOTOVIANUS, Nees. (Pl. 23.) Stems flexuous, procumbent, mostly unbranched; leaves ovate-orbicular, horizontal, the apex contracted and emarginate with a shallow sinus; underleaves large, ovate or lanceolate, obliquely inserted, entire or more often toothed on one or both sides near the middle; dioecious; perianth subcylindric, slightly sickle-shaped, the mouth pointed at first, notched on one side and finally crenulate; antheridia elliptic, single in the base of swollen leaves. (Pleuranthe olivacea, _Tayl._)--"North America" (_Drummond_), but not collected recently; certainly extralimital.

23. LIOCHLAENA, Nees. (Pl. 25.)

Leaves succubous, ovate-oblong, entire or slightly retuse; underleaves none. Dioecious or monoecious. Involucral leaves 2 or 4, like the cauline; perianth pyriform, becoming cylindric, incurved, abruptly rounded at the summit, the minute orifice prominently ciliolate. Capsule oblong, long-exserted. Elaters attached to the middle of the valves. Spores minute, globose. Antheridia in the axils of ordinary leaves. Archegonia 5--12. (Name from [Greek: lei~os], _smooth_, and [Greek: chlai na], _a cloak_, referring to the perianth.)

1. L. lanceolata, Nees. Closely creeping, branched; leaves sometimes decurrent; involucral leaves vertical; perianth at right angles with the stem; monoecious.--On banks and rotten logs; not rare. (Eu.)

24. JUNGERMANNIA, Micheli. (Pl. 25.)

Leaves succubous, rarely subtransverse, entire, lobed or dentate, the margins never recurved; underleaves present or none. Dioecious or monoecious. Fruit terminal. Involucral leaves 4 or fewer, like the cauline or more incised, free; perianth laterally compressed or terete, usually 3--10-carinate, the usually small mouth entire or toothed. Calyptra oval-pyriform. Capsule globose or oblong, rarely cylindric. Spores minute, smooth or roughish. Archegonia 8--70. (Named for _L. Jungermann_, a German botanist of the 17th century.)

Sec. 1. JUNGERMANNIA proper. _Leaves orbicular or ovate, entire or barely retuse; underleaves none (very small in n. 1)._

1. J. Schraderi, Martius. (Pl. 25.) Creeping, flexuous; leaves round-elliptic, entire, ascending; underleaves broadly subulate, not apparent on old stems; involucral leaves large, elongated, the inner smaller and more or less laciniate; perianth oval-obovate, ascending.--On the ground and rotten logs; common. (Eu.)

2. J. sphaerocarpa, Hook. Stems creeping, the tips ascending, subsimple, greenish; leaves semi-vertical, rather rigid, orbicular, obliquely spreading, decurrent dorsally, pale green; involucral leaves separate; perianth exserted, obovate-oblong, the mouth 4-cleft; capsule globose.--Mountains of N. Eng. (_Austin_); rare. (Eu.)

3. J. pumila, With. Stems creeping, the tips somewhat ascending, subsimple, rooting, pale; leaves ascending, ovate, obtuse, concave, entire; involucral leaves like the cauline, erect; perianth terminal, fusiform, plicate above and denticulate; capsule oval.--On shaded rocks along rivulets, Closter, N. J. (_Austin_). (Eu.)

Sec. 2. LOPHOZIA. _Leaves roundish or subquadrate, bidentate, bifid, or sometimes 3--5-cleft; underleaves none, or small and mostly 2-parted; perianth usually strongly plicate._

[*] _Underleaves present._

[+] _Leaves bifid or 2-lobed._

4. J. Gillmani, Aust. Stems short, densely cespitose, prostrate, strongly radiculose; leaves vertical, round-ovate, subconcave, bifid, the lower leaves with usually acute sinus and lobes, the upper much larger with rounded lobes and obtuse sinus; underleaves entire or the broader bifid; perianth without involucral leaves, dorsal, sessile, obovate, subgibbous, ciliate, at length much incised.--In a sandstone cave, Traine Island, L. Superior (_Gillman_).

5. J. Wattiana, Aust. Stems rather thick, 2--4'' long, fragile, subflexuose, strongly radiculose; leaves subvertical or spreading, subovate, concave, emarginately 2-lobed, the lobes acute or the upper obtuse; underleaves somewhat obsolete, hair-like or subulate, incurved; involucral leaves little larger, less deeply lobed; perianth terminal, small, ovate-gourd-shaped, whitish, ciliate.--On the ground, northern shore of L. Superior (_Macoun_).

[+][+] _Leaves 3--5-cleft._

6. J. barbata, Schreb. (Pl. 25.) Procumbent, sparingly branched; leaves roundish-quadrate, with obtuse, acute, or mucronulate lobes and obtuse undulate sinuses; underleaves broad, entire or 2-toothed, sometimes obsolete; perianth ovate, plicate-angled toward the apex, denticulate.--On rocks in mountain regions; common. (Eu.)

Var. attenuata, Martius. Ascending, with numerous offshoots; stem-leaves semi-vertical, obliquely spreading, roundish, acutely 2--4-toothed, those of the shoots closely imbricate, premorsely 2--4-denticulate; involucral leaves two, 3-toothed; perianth oblong.--In similar localities. (Eu.)

7. J. setiformis, Ehrh. Erect or ascending, dichotomous; leaves toothed at base, 3--4-cleft, the lobes ovate-oblong, acute, channelled; underleaves ciliate-dentate at base, deeply bifid, the divisions lanceolate, acuminate; involucral leaves more toothed than the cauline; perianth terminal, oval, plicate.--Alpine summits of N. H. (_Oakes_). (Eu.)

[*][*] _Underleaves wanting._

[+] _Leaves 2-toothed; involucral leaves 2--4-cleft._

8. J. alpestris, Schleich. Stems creeping, crowded, bifid-branching, the ends ascending; leaves semi-vertical, ovate subquadrate, obliquely toothed, the teeth unequal, acute or mucronulate, distant; involucral leaves wider, 2--3-cleft; perianth twice as long, oblong, smooth, the mouth complicate; capsule oval.--Alpine region of N. H. (_Oakes_). (Eu.)

9. J. ventricosa, Dicks. Stems dense, close-creeping, branching from beneath; leaves semi-vertical, subquadrate, mostly flat, broadly and acutely emarginate-bidentate, often bearing globules; involucral leaves larger, round, erect-spreading, 3--4-cleft, subdentate; perianth ovate, inflated, narrowly complicate above; capsule oval.--On the ground and rotten wood in the mountains, and far northward; common. (Eu.)

10. J. Wallrothiana, Nees. Minute, blackish; stems creeping, strongly rooting, subsimple; leaves clasping, semi-vertical, closely imbricate, ovate-quadrate, concave, obtusely bidentate with an obtuse sinus, or acute in the upper leaves; involucral leaves larger, erect, connate at base, 3-toothed, wavy-plicate; perianth oval-cylindric, plicate and subdentate, pellucid, reddish below.--On coarse sand in the White Mts. (_Oakes_). (Eu.)

[+][+] _Leaves bifid or 2-lobed, the ventral lobe often inflexed or subcomplicate; involucral leaves merely toothed, except in n. 11._

11. J. laxa, Lindb. Widely creeping, mostly simple, usually purplish-black; leaves imbricate, or distant on the erect fertile stems, 2--3-lobed, the lobes obtuse, wavy; cells very large, lax; involucral leaves 2, wide, short, cristate-undulate, obtusely many-lobed; perianth exserted, long-clavate, sub-plicate above, minutely ciliate. (J. polita, _Aust._; not _Nees._)--Among Sphagnum near Closter, N. J. (_Austin_).

12. J. excisa, Dicks. Stems closely creeping, short, subsimple, rather rigid; leaves semi-vertical, erect-spreading, pellucid, roundish, with straight acute lobes and deep obtuse sinus; involucral leaves erect, quadrate, usually 4--5-toothed; perianth erect, oblong, pale, banded and spotted with pink, plicate above, irregularly denticulate.--Sterile grounds in open woods; common. (Eu.)

Var. crispa, Hook. Leaves round-quadrate, closely imbricate, deeply and obtusely 2--3-cleft; involucral leaves 3--4-cleft, connate at base, subserrate. (J. intermedia, _Lindenb._)--In crevices of rocks, N. Y. and N. J. (_Austin_). (Eu.)

13. J. incisa, Schrad. Stems thick, rooting, closely creeping or ascending; leaves crowded, semi-vertical, complicate, subquadrate, 2--6-cleft, the acute lobes unequal, more or less spinulose-dentate; involucral leaves similar, more plicate and dentate, free; perianth short, oval or obovate, plicate above, denticulate.--On rotten wood in the mountains, and northward. (Eu.)

Sec. 3. SPHENOLOBUS. _Leaves 2-lobed, subtransverse, complicate-concave; underleaves none; involucral leaves 2--3-cleft._ (Verging toward Marsupella on one side and Diplophyllum on the other.)

14. J. Michauxii, Weber. Stems ascending, flexuous by repeated innovations below the summit; leaves crowded, subvertical, erect-spreading, subsaccate at base, subquadrate, bifid with straight acute lobes and a narrow sinus; involucral leaves similar, the outer serrulate, the inner smaller; perianth ovate-subclavate, obtuse, plicate above, fringed.--Fallen trunks, mountains of N. Y. and N. Eng.; common. (Eu.)

15. J. minuta, Crantz. Rootless; leaves cleft 1/4--1/2 their length, the lobes ovate, subequal, acute or obtuse, entire, or gemmiparous ones subdentate; involucral leaves trifid; perianth oval-oblong or subcylindric.--On rocks in high mountain regions, and northward. (Eu.)

16. J. Helleriana, Nees. (Pl. 25.) Creeping, entangled; leaves spreading, subascending, cleft {1/3}--1/2 their length, the lobes equal, acute, entire or serrate; involucral leaves 2--3-cleft, spinulose serrate; perianth ovate, the mouth contracted.--On rotten wood, N. Y., N. Eng., and northward. (Eu.)

Sec. 4. GYMNOCOLEA. _Leaves 2-lobed; underleaves none; involucral leaves like the cauline; perianth pedunculate, denticulate._

17. J. inflata, Huds. (Pl. 25.) Procumbent or ascending, loosely radiculose, branching; leaves semi-vertical, roundish-elliptic, inequilateral, the sinus and unequal lobes obtuse; perianth terminal or at length dorsal, oval or pyriform, smooth, the mouth connivent; capsule oblong.--On sterile ground and rocks, N. J. (_Austin_), and northward in the mountains. (Eu.)

25. MARSUPELLA, Dumort. (Pl. 23.)

Stems dorsally compressed, with rootlets at the base and often producing somewhat leafless runners. Leaves transverse, complicate-bilobed; involucral leaves 2 or 4, connate with the perianth. Perianth tubular or oval, subcompressed parallel to the base of the leaves. Elaters free. Spores round, rufous (in our species). Antheridia mostly terminal. (Name a diminutive of _marsupium_, a pouch, from the form of the perianth.)

1. M. sphacelata, Dumort. Stems erect, subflexuous, pale brown; leaves rather distant, concave, obovate to obcordate, somewhat clasping, the sinus narrow; dioecious; involucral leaves larger than the cauline, cordate; perianth free at the apex, with 4--5 broad acute teeth; antheridia 1--3, in short terminal spikes.--Wet rocks, mountains of N. Eng. to N. J., and southward. (Eu.)

2. M. emarginata, Dumort. (Pl. 23.) Stems simple or innovating at the summit, rigid, somewhat thickened upward; leaves usually broader than long, round-cordate or subquadrate, lobes obtuse or mucronate, sinus acute; dioecious; involucral leaves 4--8, usually larger, more deeply and acutely emarginate; perianth urceolate, the closed apex splitting into 4--5 triangular lobes; antheridia 2--3, oval, axillary in terminal spikes. (Sarcoscyphus Ehrharti, _Corda._)--On wet rocks, chiefly in mountain rivulets, N. Y. and N. Eng. Floating forms are longer with distant leaves. (Eu.)

3. M. adusta, Spruce. Stems minute, clavate; leaves (5--8 pairs) imbricate, round or broadly ovate from a sheathing base, acutely lobed with angular sinus; monoecious; perianth included, campanulate, crenate becoming irregularly lobed; spores punctate; antheridia 1 or 2, oval, in the axils of the lower involucral leaves. (Gymnomitrium adustum, _Nees._)--Alpine region of the White Mts. (_Oakes, Austin_). (Eu.)

26. NARDIA, S. F. Gray. (Pl. 25)

Stems laterally compressed, usually without runners. Leaves succubous, subconcave or flat, the apex rounded, rarely retuse or bidentate; underleaves none (in our species). Monoecious or dioecious. Involucral leaves 2--4 pairs, connate at base. Perianth subcompressed laterally, connate with the involucral leaves. Antheridia terminal on somewhat spike-like stems. (Named for _S. Nardi_, an Italian abbot.)

Sec. 1. EUCALYX. _Perianth connate at base with the inner involucral leaves, somewhat surpassing them, 3--8-carinate, the mouth constricted._

1. N. hyalina, Carring. Creeping, with ascending tips, the branches dichotomous-fastigiate, with claret-colored rootlets; leaves loosely imbricate, decurrent, roundish, repand-undulate; monoecious or dioecious; involucral leaves broader, appressed, one connate with the lower third of the perianth, which is somewhat exserted, obovate, plicate with acute rough angles, rostellate, at length 4-cleft; capsule round-ovate. (Jungermannia hyalina, _Lyell_.)--On banks in woods, Closter, N. J. (_Austin_), Ohio (_Lesquereux_). (Eu.)

2. N. crenulata, Lindb. (Pl. 25.) Prostrate, branching; leaves orbicular, entire, larger toward the involucre and with large marginal cells; dioecious; involucral leaves 2, rarely 3, adnate to the base of the perianth, which is flattened or terete, more or less regularly 4--5-plicate, the angles smooth; mouth much contracted, toothed. (Jungermannia crenulata, _Smith_.)--On the ground in old fields, N. Y. and southward. (Eu.)

3. N. crenuliformis, Lindb. Densely cespitose; fertile stems creeping, thickened upward, with numerous purple rootlets, the sterile subascending, attenuate upward; leaves subdecurrent, obliquely spreading, orbicular, concave, entire or nearly so; perianth small, subobovate, more or less connate with the involucral leaves, not exserted or slightly so, rooting at base, triquetrous above, becoming 4--7-plicate; calyptra often violet-purple; capsule oval-globose. (Jungermannia crenuliformis, _Aust._)--On rocks in rivulets, Closter, N. J. (_Austin_), Coshocton Co., Ohio (_Sullivant_).

4. N. biformis, Lindb. Densely cespitose, much branched, innovating from beneath; rootlets numerous; leaves scarcely imbricate, alternate, spreading, obliquely semicircular or broadly ovate, retuse or entire, decurrent dorsally; cells large, hyaline; branch-leaves half as large, ovate or obovate, scarcely decurrent; dioecious; antheridia solitary; fruit unknown. (Jungermannia biformis, _Aust._)--On steep wet rocks, Delaware Water Gap, N. J. (_Austin_).

Sec. 2. CHASCOSTOMA. _Perianth exserted, subcampanulate and open, deeply laciniate, connate with the involucral leaves._

5. N. fossombronioides, Lindb. Stems densely cespitose, ascending; rootlets numerous, purple; leaves 2-ranked, subvertical, spreading-subrecurved, rooting, closely imbricate, orbicular, clasping by a slightly cordate base, subventricose, undulate-repand, the apex uniplicate and slightly emarginate; monoecious; perianth very large, 6--10-plicate, the lobes entire; calyptra violet; capsule short-oval. (Jungermannia fossombronioides, _Aust._)--On rocks in a rivulet, Closter, N. J. (_Austin_), and southward.

27. GYMNOMITRIUM, Corda. (Pl. 23.)

Leaves closely imbricated, 2-ranked on fascicled ascending julaceous stems, emarginate-bidentate; underleaves none. Dioecious. Involucre double, the inner shorter, of 2 or more dentate and deeply cleft leaves. Calyptra short, campanulate. Capsule globose, the valves at length reflexed. Elaters caducous. Antheridia in the axils of leaves, oval, stipitate. (Name from [Greek: gymno/s], _naked_, and [Greek: mitri/on], _a little cap_.)

1. G. concinnatum, Corda. Stems simple or imbricately branching, thickened at the apex; leaves ovate, bifid, with a narrow scarious margin. (Cesia concinnata, _S. F. Gray_.)--Alpine regions of the White Mts. (_Oakes_).--Grayish or silvery-olive. (Eu.)

28. FOSSOMBRONIA, Raddi. (Pl. 23.)

Stems thalloid, with large subquadrate succubous leaves; underleaves none. Dioecious or monoecious. Fruit terminal or by innovation dorsal on the main stem. Involucral leaves 5--6 (in our species), small, subulate, adnate. Perianth open-campanulate or obpyramidal, crenate-lobed. Calyptra free, sub-globose. Capsule short-pedicelled, globose, irregularly valved. Elaters very short, 1--3- (mostly 2-) spiral, free. Spores large, very rough. Antheridia 2--3, short-pedicelled, naked. Perfect archegonia 2--3. (Named for _V. Fossombroni_, an Italian Minister of State.)

[*] _Plant large or of medium size; stems mostly simple._

1. F. pusilla, Dumort. (Pl. 23.) Stems 6--10'' long; leaves retuse, entire or irregularly indented; perianth obconic, dentate; elaters short and thick; spores brown, depressed-globose-tetrahedral, 40 mu broad, crested, the slender crests pellucid, rarely becoming confluent.--On damp ground. Its occurrence in America is doubtful. (Eu.)

2. F. Dumortieri, Lindb. Cespitose, greenish or brownish-yellow; stems 3--6'' long, 1'' wide, shortly bifurcate; rootlets copious, purple; leaves numerous, smaller toward each end of the stem; monoecious; perianth large, broadly obpyramidal; calyptra nearly as long; elaters scanty; spores globose-tetrahedral yellowish-brown, regularly pitted.--White Mts. (_Farlow_), N. J. (_Austin_), and perhaps elsewhere; confused with n. 1.

3. F. angulosa, Raddi. Stems narrowly forked at the apex; leaves horizontal, subquadrate, the upper undulate-lobed; dioecious; perianth dilated-conic, crenate; spores brownish-yellow, globose-tetrahedral, not depressed, 30 mu broad, deeply reticulated, the reticulations large, 5--6-angled.--Brackish meadows, common; fruiting in early spring. (Eu.)

[*][*] _Plant minute; stems forked or fastigiately divided._

4. F. cristula, Aust. Stems 1--2'' long; leaves whitish, quadrate or round-obovate, subentire, strongly crisped-undulate; capsule immersed on a short pedicel; elaters short, more or less diverse, with a single narrow annular and spiral fibre; spores pale fuscous, more or less tuberculate.--On moist sand in unfrequented paths, Batsto, N. J. (_Austin_).

29. PALLAVICINIA, S. F. Gray. (Pl. 22.)

Thallus with a distinct costa. Fruit arising from the costa, at first terminal, becoming dorsal. Dioecious. Involucre cup-shaped, short-lacerate. Perianth long-tubular, denticulate. Calyptra irregularly lacerate. Capsule slender-cylindric. Elaters slender, free. Spores minute. Antheridia dorsal, covered with minute fimbriate scales. (Named for _L. Pallavicini_, Archbishop of Genoa.)

1. P. Lyellii, S. F. Gray. Thallus thin, 1--4' long, 3--5'' wide, simple or bifid, the margin entire, slightly crenate or serrate; cells large, oblong-hexagonal; perianth erect, fleshy (5 cells thick below), the somewhat constricted mouth lobate-ciliolate; pedicel long, exceeding the thallus; capsule cylindric, five times as long as broad. (Steetzia Lyellii, _Lehm._)--Among mosses in swamps and on dripping rocks; common, especially southward. (Eu.)

30. BLASIA, Micheli. (Pl. 23.)

Thallus simple or forked or stellate, with sinuous margins. Dioecious. Fruit from an oval cavity in the costa. Involucre mostly none. Calyptra obovate. Capsule oval-globose. Antheridia immersed in the thallus, covered with dentate scales. Gemmae globose, issuing by a slender ascending tube from large flask-shaped receptacles which are immersed in the thallus. (Named for _Blasius Biagi_, a monk of Valombrosa and companion of Micheli.)

1. B. pusilla, L. Thallus 3/4--11/2' long, 2--3'' wide, narrowly obovate, the margins pinnatifid-sinuous.--Wet banks; common. (Eu.)

31. PELLIA, Raddi. (Pl. 23.)

Thallus with a broad indeterminate costa. Monoecious or dioecious. Fructification dorsal near the end of the thallus. Involucre short, cup-shaped, lacerate-dentate. Calyptra membranous, oval, longer or shorter than the involucre. Capsule globose. Elaters long, free. Antheridia globose, immersed in the costa. (Named for _A. L. Pelli_, an Italian botanist.)

[*] _Monoecious._

1. P. epiphylla, Raddi. (Pl. 23.) Thallus oblong, lobed and sinuate, somewhat fleshy, much thickened in the middle; capsule exserted.--On the ground in wet places; not uncommon eastward. (Eu.)

[*][*] _Dioecious._

2. P. endiviaefolia, Dumort. Thallus flat, green or purplish, broadly linear, dichotomous, the margin mostly undulate or crisped.--On the ground and in ditches; common, but often confused with n. 1. (Eu.)

3. P. calycina, Nees. Thallus dichotomous, proliferous, the early divisions linear-oblong, the margins ascending and remotely sinuate, the later divisions linear-palmatifid, coarsely nerved; cells large, hexagonal; involucre ciliate-fringed or lacerate; calyptra smooth, included.--Wet limestones and shales. (Eu.)

32. METZGERIA, Raddi. (Pl. 23.)

Thallus linear, dichotomous, with well defined costa. Dioecious. Fructification arising from the under side of the costa. Involucre 1-leaved, scale-like, at length ventricose. Calyptra clavate or pyriform, fleshy. Capsule short-pedicelled. Elaters unispiral, some remaining attached to the tips of the valves. Spores minute, mostly smooth. Antheridia globose, enclosed in a scale on the under surface of the costa. (Named for _J. Metzger_, a German botanist.)

[*] _Densely villous throughout._

1. M. pubescens, Raddi. Thallus 1--2' long, 1'' wide, alternately pinnate or somewhat decompound, the short linear branches of uniform width, flat, the margin undulate; hairs longer beneath, single or in twos and threes near the margin, irregularly curved; midrib nearly without cortical layer, with 6--10 (mostly 8) rows of very uniform peripheral cells; dioecious.--In mountain regions, eastward. (Eu.)

[*][*] _Hairy on the margins and midrib beneath, smooth above; dioecious (n. 4 monoecious)._

2. M. myriopoda, Lindb. Thallus elongated (2' long, 1/2'' wide), dichotomous, the long linear branches of uniform width, convex above, the reflexed margins not undulate; midrib densely pilose beneath; hairs rather long, straight or nodding, the marginal mostly in clusters of 3--6, some with discoid tips; midrib covered above with 2 rows of enlarged cells, and beneath with 3--7 (usually 4--6) rows of smaller cells, lax and often indistinct. (M. furcata, _Sulliv._, in part; not _Nees._)--Shaded rocks and trees in the Alleghanies (_Sullivant_), and southward.

3. M. hamata, Lindb. Like the last; thallus much elongated (4' long, 1--11/2'' wide); hairs very long, divaricate and hooked-deflexed, the marginal in twos, rarely with discoid tips; midrib covered above and below with two rows of enlarged lax cells. (M. furcata, _Sulliv._, in part.)--Alleghany Mts. (_Sullivant_).

4. M. conjugata, Lindb. Thallus 11/2' long, 1/2--1'' wide, usually dichotomous, the short branches irregular in width, convex above, the margins more or less undulate; hairs rather long, straight, divaricate, the marginal usually in twos, very often disk-bearing; midribs covered above with 2, below with 3--6 rows of enlarged lax cells.--On shaded rocks and trunks of trees, central N. Y., and southward. (Eu.)

33. ANEURA, Dumort. (Pl. 23.)

Thallus fleshy, prostrate or assurgent from a creeping base; costa obscure. Dioecious or monoecious. Fructification arising from the under side near the margin. Involucre cup-shaped, short and lacerate, or none. Calyptra large, fleshy, more or less clavate. Capsule large, oblong-cylindric. Elaters unispiral, in part adherent to the tips of the valves. Spores minute, smooth or minutely roughened. Antheridia immersed in the surface of receptacles proceeding from the margin of the thallus. (Name from [Greek: a]- privative, and [Greek: neu~ron], a nerve.)

[*] _Thallus narrow (about 1'' wide), palmately divided._

1. A. latifrons, Lindb. Thallus cespitose, ascending or erect, usually dark green, 6--9'' long, mostly pellucid; branches linear, obtuse and emarginate, plano-convex; cells large, oblong-rhombic; monoecious; archegonia 3--10, short, conic; calyptra white, verrucose, pyriform-clavate; capsule oval, brown; spores 121/2--141/2 mu broad, globose, minutely and densely papillose; antheridia globose. (A. palmata of authors; not _Dumort_.)--On rotten logs; common.

[*][*] _Thallus narrow (about 1'' wide), pinnate or bipinnate._

2. A. multifida, Dumort. Thallus prostrate, brownish-green, pinnately divided, the primary portion biconvex, somewhat rigid, the branches horizontal, pectinately pinnate with narrow linear divisions; monoecious; fructification rising from the primary part or from the branches; involucre fleshy; calyptra tuberculate.--Var. MAJOR, Nees. Primary portion and branches thick, the branches interruptedly pinnate with short obtuse divisions.--On decayed wood and moss in swamps, N. J. (_Austin_), and south in the mountains. (Eu.)

3. A. pinnatifida, Nees. Thallus pinnately divided or subsimple, flat or somewhat channelled; branches horizontal, the broader pinnatifid or dentate, obtuse; calyptra somewhat smooth.--On dripping rocks, Hokokus, N. J. (_Austin_), N. Haven, Conn. (_Eaton_). (Eu.)

[*][*][*] _Thallus wider (2'' or more), simple or irregularly lobed._

4. A. sessilis, Spreng. Thallus decumbent, irregularly lobed, 1--2' long, 3--5'' wide; involucre none; pedicel 3/4--1' long, sometimes folded upon itself and remaining within the calyptra, the capsule thus appearing sessile; antheridia on elongated receptacles.--Wooded swamps. Elongated floating forms, 5--6' long, have been found in the White Mts. (_Farlow, Faxon_).

5. A. pinguis, Dumort. Thallus 1--2' long, decumbent or ascending, fleshy, linear-oblong, simple or slightly lobed, the margin sinuate; dioecious; involucre short, lacerate; calyptra cylindric, smooth; capsule brownish, furrowed; antheridia in 2-lobed receptacles.--Wet banks, N. J. to Ohio, and southward. (Eu.)

ORDER 138. ANTHOCEROTACEAE. (HORNED LIVERWORTS.)

Plant-body a thallus, irregularly branching, flaccid, without epidermis or pores, and more or less vesiculose. Involucre single, tubular. Calyptra rupturing early near the base, and borne on the apex of the capsule. Capsule dorsal, pod-like, erect or curved outward, more or less perfectly 2-valved, usually stomatose, tapering into a pedicel or often sessile with a bulbous base. Columella filiform. Elaters with or without spiral fibres. Spores flattish, more or less convex-prismatic, papillose or smooth.

1. Anthoceros. Capsule narrowly linear, exsertly pedicelled, 2-valved. Elaters present.

2. Notothylas. Capsule very short, sessile, not valved below the middle. Elaters not obvious.

1. ANTHOCEROS, Micheli. (Pl. 22.)

Thallus dark green or blackish, usually depressed, variously lobed, with large chlorophyll-grains, frequently glandular-thickened at the apex or in lines along the middle so as to appear nerved. Monoecious or dioecious. Capsule linear, 2-valved, exsertly pedicelled. Elaters simple or branched, often geniculate, more or less heteromorphous, the fibres wanting or indistinct. (Name from [Greek: a)/nthos], _flower_, and [Greek: ke/ras], _horn_, from the shape of the capsule.)

1. A. laevis, L. (Pl. 22.) Thallus smooth, nearly flat above; dioecious; involucre 1--2'' long, trumpet-shaped when dry, repand-toothed; capsule pale brown or yellowish, 1--11/2' long; elaters rather short, yellowish; spores yellow, nearly smooth, angular.--Wet clay banks, from Canada south and westward. (Eu.)

2. A. punctatus, L. Thallus small, depressed, or often cespitose and erect, more or less glandular; monoecious; involucre rather short, oblong-linear, slightly repand, sometimes scarious at the mouth; capsule 1' high, black; elaters fuscous, flattish, geniculate; spores black, strongly muriculate, sharply angled.--Wet banks, Canada to Mo., and southward. (Eu.)

2. NOTOTHYLAS, Sulliv. (Pl. 22.)

Thallus orbicular, tender, laciniate and undulate or crisped, papillose-reticulate. Monoecious. Involucre sessile, continuous with the thallus, opening irregularly above. Capsule very short, oblong-globose or ovate-cylindric, pedicelled from a thickened bulb, 2-valved to the middle or rupturing irregularly. Elaters none, or fragmentary and inconspicuous. Spores subglobose, smoothish. Antheridia elliptic-globose, immersed in the thallus. (Name from [Greek: no~tos], _the back_, and [Greek: thyla/s], _a bag_, from the shape and position of the involucre.)

1. N. orbicularis, Sulliv. (Pl. 22.) Thallus 3--8'' wide; capsules 1--2'' long, erect or decurved, wholly included or slightly exserted, of thin and loose texture, with a suture on each side; spores light yellowish-brown. (Including N. valvata, _Sulliv._)--Wet places, Canada to the Gulf.

2. N. melanospora, Sulliv. Thallus small, depressed or sometimes cespitose, of lax texture; capsule often without sutures; spores dark brown, a half larger.--Moist ground, Ohio (_Sullivant_).

ORDER 139. MARCHANTIACEAE. LIVERWORTS.

Plant-body a thallus, dichotomous or subpalmately branching, usually innovating from the apex or beneath it, more or less thickened in the middle, and bearing numerous rootlets beneath and usually colored or imbricating scales. Epidermis usually more or less distinct and strongly porose above. Capsules globose, rarely oval, opening irregularly, pendent from the under side of a peduncled disk-like receptacle (_carpocephalum_). Elaters present, mostly 2-spiral.

[*] Thallus plainly costate, distinctly porose except in n. 6.

[+] Gemmae present on sterile stems.

1. Marchantia. Gemmae in cup-shaped receptacles. Fertile receptacle 7--11-rayed.

8. Lunularia. Gemmae in crescent-shaped receptacles. Fertile receptacle cruciform.

[+][+] Gemmae wanting.

[++] Receptacle conic-hemispherical, 2--4-lobed; perianth lobed or fringed.

2. Preissia. Receptacle 2--4-lobed, with as many alternate rib-like rays. Perianth 4--5-lobed.

3. Fimbriaria. Receptacle 4-lobed. Perianth conspicuous, split into 8--16 fringe-like segments.

[++][++] Receptacle more or less conical; perianth none.

4. Conocephalus. Thallus very large, strongly areolate. Receptacle conical, membranous.

5. Grimaldia. Thallus small. Peduncle chaffy at base and apex. Receptacle conic-hemispheric, truncately 3--4-lobed.

6. Asterella. Thallus eporose. Receptacle conic-hemispheric, becoming flattened, acutely 4- (1--6-) lobed.

[*][*] Thallus thin, ecostate or barely costate.

7. Dumortiera. Receptacle convex, 2--8-lobed. Perianth none.

1. MARCHANTIA, Marchant f. (Pl. 22.)

Thallus large, forking, areolate, porose, with broad diffused midrib; gemmae in a cup-shaped receptacle. Dioecious. Fertile receptacle peduncled from an apical sinus of the thallus, radiately lobed. Involucres alternate with the rays, membranous, lacerate, enclosing 3--6 1-fruited cleft perianths. Calyptra persistent. Capsule globose, exserted, pendulous, dehiscing by several revolute segments. Elaters long, attenuate to each end. Spores smooth. Antheridia immersed in a peduncled disk-like radiate or lobed receptacle. (Named for _Nicholas Marchant_, a French botanist.)

1. M. polymorpha, L. Thallus 2--5' long, 1/2--11/2' wide, numerously porose, venulose; receptacle divided into usually 9 terete rays; peduncles 1--3' high; antheridial disk crenately or palmately 2--8-lobed, on a peduncle 1' high or less.--Everywhere common. (Eu.)

2. PREISSIA, Nees. (Pl. 22.)

Thallus obcordate, sparingly forked, increasing by joints; pores conspicuous; gemmae none. Dioecious or monoecious. Fertile receptacle hemispheric, 1--4-lobed, with as many alternating shorter rib-like rays. Outer involucres attached beneath the lobes, 1--3-fruited, opening outward by an irregular line; perianth obconic-campanulate, angular, unequally 4--5-lobed. Calyptra persistent. Capsule large, distinctly pedicelled, dehiscing by 4--8 revolute segments. Elaters short. Spores coarsely tuberculate. (Named for _L. Preiss_, a German botanist.)

1. P. commutata, Nees. Thallus 1--2' long, with conspicuous white pores above, and dark purple scales beneath; usually monoecious; peduncle 1/2--1' high; capsules conspicuous, dark purple; antheridia in a peduncled disk-like receptacle. (P. hemisphaerica, _Cogn._)--On slaty and limestone rocks, from N. J. north and westward. (Eu.)

3. FIMBRIARIA, Nees. (Pl. 22.)

Thallus thickened in the middle by a keeled costa, usually conspicuously porose, with dark purple scales beneath; gemmae none. Monoecious. Receptacle rising from the apex, conic or hemispheric, concave beneath and expanded into usually 4 large campanulate 1-fruited involucres. Perianth oblong-oval or subconic, exserted half its length and cleft into 8--16 fringe-like segments. Calyptra with a long style, fugacious. Capsule nearly sessile, irregularly circumscissile. Elaters rather short, 1--4-spiral. Spores angular, subreticulated. Antheridia immersed in the thallus. (Name from _fimbria_, a fringe, alluding to the perianth.)

1. F. tenella, Nees. Thallus of one or more long-wedge-shaped emarginate divisions about 6--9'' long, grayish-green and porose above, purple on the margins; peduncle 1' high or more, usually purple; receptacle obtusely conic; perianth white, 8-cleft.--On damp ground in sandy fields or on rocks, central N. Y. to Mo., and southward.

4. CONOCEPHALUS, Neck. (Pl. 22.)

Thallus dichotomous, copiously reticulate and porose, with a narrow costa; gemmae none. Receptacle conic-mitriform, membranous. Involucres 5--8, tubular, 1-fruited, suspended from the apex of the peduncle; perianth none. Calyptra persistent, campanulate, 2--4-lobed at the apex. Capsule pedicelled, oblong-pyriform, dehiscing by 5--8 revolute segments. Elaters short, thick. Spores muriculate. Antheridia imbedded in an oval disk sessile near the apex of the thallus. (Name from [Greek: ko nos], _a cone_, and [Greek: kephale/], _a head_.)

1. C. conicus, Dumort. Thallus 2--6' long, 1/2--3/4' wide; receptacle conic, striate, crenate. (Fegatella conica, _Corda._)--Shady banks; common. (Eu.)

5. GRIMALDIA, Raddi. (Pl. 23.)

Thallus thick, more or less channelled, dichotomous, innovating from the apex, with thick epidermis, closely areolate and porose-scabrous above, purple and more or less scaly beneath; gemmae none. Monoecious or dioecious. Receptacle peduncled, hemispherical or conoidal, 3--4-lobed. Involucres as many, 1-fruited, each a distention of the lobe. Capsule filling the involucre, circumscissile in the middle, the calyptra persistent at its base. Antheridia in an oval or obcordate disk immersed in the apex of the thallus. (Named for _D. Grimaldi_, an Italian botanist.)

1. G. barbifrons, Bisch. (Pl. 23.) Thallus linear-obcuneate, 3--6'' long, 1--2'' wide, 2-lobed at the apex, pale green with usually distinct whitish pores, the scales beneath often extending far beyond the margin and becoming whitish; peduncle profusely chaffy at base and apex, sometimes much reduced; antheridial disks obcordate. (Including G. sessilis, _Sulliv._)--Thin soil on rocks, Conn. and N. J. to Iowa; rare or local. (Eu.)

2. G. rupestris, Lindenb. Thallus 3--6'' long, 1--3'' wide, with membranous margins; receptacle small, hemispherical, 1--4-fruited, the peduncle about 1' high, sparingly scaly at base, barbulate at the apex; involucre short, crenulate; spores tuberculate. (Duvalia rupestris, _Nees_.)--On calcareous or shaly rocks, N. Y. and Ohio. (Eu.)

6. ASTERELLA, Beauv. (Pl. 22.)

Thallus rigid, very indistinctly porose, the midrib broad, strong and distinct. Receptacle conic-hemispheric, becoming flattened, 1--6- (usually 4-) lobed. Monoecious. Involucres coherent with the lobes, 1-fruited, 2-valved. Calyptra minute, lacerate, persistent at the base of the capsule. Capsule greenish, rupturing by irregular narrow teeth or by a fragmentary operculum. Elaters moderately long, mostly 2-spiral. Spores tuberculate. Antheridia in sessile lunate disks. (Diminutive of _aster_, a star, from the form of the receptacle.)

1. A. hemisphaerica, Beauv. Thallus forking and increasing by joints, pale green, purple beneath; receptacle papillose on the summit (less so at maturity); peduncle bearded at base and apex, 3/4--1' long, often 2--3 times longer after maturity. (Reboulia hemisphaerica, _Raddi._)--Shaded banks, chiefly along streams; more common southward.--A smaller form or perhaps variety (Reboulia microcephala, _Nees_; R. Sullivantii, _Lehm._) occurs in Penn., Ohio, and southward. (Eu.)

7. DUMORTIERA, Nees. (Pl. 22.)

Thallus large, thin, soft, with a slight costa, dichotomous, usually with scattered hair-like rootlets beneath; gemmae none. Receptacle convex, 2--8-lobed. Involucres 1-fruited, connate with the lobes beneath, horizontal, opening by a vertical terminal slit. Capsule distinctly pedicelled, oblong-globose, dehiscing by 4--6 irregular valves. Elaters 2--3-spiral, parietal, very long, straight, attenuate both ways. Spores muriculate. Antheridia in a short peduncled disk paleaceous beneath. (Named for _B. C. Dumortier_, a Belgian botanist.)

1. D. hirsuta, Nees. Thallus 2--5' long, 6--9'' wide, deep green, becoming blackish, entire on the margins, naked above or with a delicate appressed pubescence; dioecious; receptacle many-fruited, the margin closely hairy; peduncle rather long, chaffy at the apex.--On moist calcareous rocks, Easton, Penn. (_Porter_), and southward.

8. LUNULARIA, Micheli. (Pl. 25.)

Thallus oblong with rounded lobes, distinctly areolate and porose, with imbricate sublunate scales beneath; gemmae in crescent-shaped receptacles. Dioecious. Fertile receptacle usually cruciately divided into 4 horizontal segments or involucres, which are tubular, vertically bilabiate and 1-fruited. Calyptra included, persistent. Capsule exserted, 4--8-valved. Elaters short, very slender, mostly free. Spores nearly smooth. Antheridia borne in the apical sinus of the thallus. (Name from _lunula_, a little moon.)