Thallus large, forking, areolate, porose, with broad diffused midrib; gemmae in a cup-shaped receptacle. Dicious. 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' 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. PRESSIA, Nees. (Pl. 22.)

Thallus obcordate, sparingly forked, increasing by joints; pores conspicuous; gemmae none. Dicious or moncious. 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 coa.r.s.ely 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 moncious; peduncle --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. Moncious.

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 circ.u.mscissile. 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 ?????, _a cone_, and ?efa??, _a head_.)

1. C. conicus, Dumort. Thallus 2--6' long, --' 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. Moncious or dicious. Receptacle peduncled, hemispherical or conoidal, 3--4-lobed.

Involucres as many, 1-fruited, each a distention of the lobe. Capsule filling the involucre, circ.u.mscissile 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. Moncious. 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. hemisphae'rica, 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, --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 p.u.b.escence; dicious; 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. Dicious. Fertile receptacle usually cruciately divided into 4 horizontal segments or involucres, which are tubular, vertically bil.a.b.i.ate 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.)

L. VULGaRIS, Raddi. Thallus 1--2' long, forked, innovating from the apex, with a somewhat diffuse costa; peduncle very hairy, 1--1'

long.--Introduced into greenhouses; always sterile, but easily recognized by the characteristic receptacles. (L. cruciata, _Dumort._) (Int. from Eu.)

ORDER 140. RICCIaCEae.

Plant-body a dichotomously branching thallus, terrestrial or aquatic.

Capsules short-pedicelled, or sessile on the thallus, or immersed in its substance, free or connate with the calyptra, globose, at length rupturing irregularly. Calyptra crowned with a more or less deciduous point. Elaters none. Spores usually angular, reticulate or muriculate.

Antheridia ovate, immersed in the thallus in flask-shaped cavities with protruding orifices (_ostioles_).

1. Riccia. Capsule immersed in the thallus. Involucre none.

2. Sphaerocarpus. Capsule sessile on the thallus. Involucre inflated-pyriform.

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

Thallus at first radiately divided, the centre often soon decaying; the divisions bifid or di--tri-chotomous, flat or depressed or channelled above, usually convex and naked or squamulose beneath; margins naked or spinulose-ciliate; epidermis usually distinct, eporose; air-cavities evident or wanting. Capsule immersed, sessile. Calyptra with a persistent style. Spores alveolate or muriculate, usually flattened and angular. (Named for _P. F. Ricci_, an Italian n.o.bleman, patron of Micheli.)

-- 1. LICHENDES. _Fruit mostly protuberant above; spores about 84 broad, issuing through openings in the upper surface of the thallus; terrestrial species (on damp, usually trodden or cultivated ground), without air-cavities._

[*] _Thallus naked, without cilia or scales._

1. R. Frostii, Aust. Thallus...o...b..cular, 6--12" broad, thinnish, grayish-green, the apex and narrowly membranous margins sometimes purplish, minutely pitted; divisions linear or subspatulate, subtruncate and slightly emarginate; rootlets smooth or obsoletely papillose within; capsules very prominent beneath; spores barely 50 broad, nearly round, somewhat margined, with depressed sides when dry, fuscous.--Ohio, Ill., and westward.

[*][*] _Thallus with white scales beneath (dark purple in n. 4), the margin naked._

2. R. sorocarpa, Bisch. Thallus 3--8" in diameter, pale green becoming whitish, finely reticulate, subradiately or dichotomously divided, the oblong-linear segments subacute, deeply sulcate, with a few inconspicuous scales toward the apex not extending beyond the margin; margins erect when dry; spores issuing through c.h.i.n.ks early appearing along the groove above.--Thin rocky soil and cultivated fields, Closter, N. J. (_Austin_), western N. Y. (_Clinton_), and Ill. (_Hall_). (Eu.)

3. R. lamellsa, Raddi. Thallus pale green, elegantly reticulated, subradiately divided, the divisions obovate or obcordate, bifid or 2-lobed, 2--5" long, channelled at the apex, with membranous ascending margins, and furnished beneath with transverse scales which extend considerably beyond the margin; spores much as in n. 2.--Thin rocky soil, Closter, N. J. (_Austin_).

4. R. nigrella, DC. Thallus dichotomously divided, the divisions linear, channelled, with entire narrowly membranous margins, green above, dark purple beneath and furnished with transverse semicircular scales not exceeding the margin.--Rocky ground, N. Y. (_Torrey_), and Chester, Penn. (_Porter_). (Eu.)

[*][*][*] _Thallus more or less ciliate, naked beneath or obsoletely squamous along the extreme edge._