64. P. vitellina, Ach. Cr. tartareous, granulose-coacervate, darkreddish-yellow; hypoth. macular, white; apoth. sessile, disk yellow becoming fuscous, margin simple, thin, erect, entire, at length of the same color. Fr. Lichenogr. p. 162. Lecanora, Ach.

Dead wood and rocks; New England. Pennsylvania, Muhl.

65. P. fulva, Schwein. (sub Lecanora). Cr. cartilagineous, chinky and granulate-verrucose, sulphureous or pallescent, upon a blackish hypothallus; apoth. sessile, disk reddish-orange, immarginate, with a thick, inflected, at length flexuous margin. Lecanora fulva, Schwein. in Hals. Lich, N. Y. l. c. p. 13. Tuckerm. Lich. N. E. 1. c. Trunks; New England. New York, Halsey.

66. P. cerina, Ach. Cr. at first contiguous, at length granulate, cinereous, upon a bluish-black hypothallus; apoth. sessile, disk immarginate, somewhat wax-colored, with a thin, equal, opake, entire thalline margin. Fr. Lichenogr. p. 160. Lecanora, Ach.

Trunks, rocks, and stones; New England. Pennsylvania, Muhl.

Subsect IX. URCEOLARIA, Fr.

67. P. glaucoma, Ach., Fr. Crust tartareous, contiguous, rimoseareolate, glaucous-white; hypothallus white; apothecia innate, disk pale-flesh-colored, pruinose, at length convex, and becoming blackish, with a very entire, evanescent thalline margin. Fr. Summ. Fl. Scand. P. sordida, Fr. Lichenogr. p. 178. Lecanora glaucoma, Ach.

Rocks (especially granite). New York, Halsey. Arctic America, Rich.

68. P. verrucosa, Ach., Fr. Cr. cartilagineous, verrucose, naked, glaucous-white; hypoth. white; disk immersed in the verrucæ, concave, blackish, subpruinose, the proper margin connate with the convex thalline margin. Fr. Lichenogr. p. 186. Icon, Laur. in Sturm's Fl. t. 21.-a. Urceolaria, Fr.; normal. Urceolaria verrucosa, Ach. 8. Pertusaria, Fr.; verrucæ closed, disk prominent like a black ostiole. Porina glomerata, Ach.

Incrusting dead mosses and sticks, in alpine districts; White Moun

tains.

69. P. calcarea, Ach., Fr. Cr. subcartilagineous, areolate-verrucose, glaucescent (often mealy and white); disk immersed in the areolæ, from concave becoming plane, blackish, cæsious-pruinose, with a

thin, at length discrete, entire proper margin; thalline margin somewhat prominent, subentire, or rugose-crenate. Fr. Lichenogr. p. 187. Urceolaria, Ach.

Limestone, and from this passing to other rocks; New England. New York, Halsey.

70. P. scruposa, Sommerf. Cr. tartareous, rugose-granulate, glaucous-cinerascent; hypoth. white; apoth. immersed, disk urceolate, cæsious-black, with a connivent, cinerous-blackish proper margin, which is at first covered by the crenate thalline margin. Fr. Lichenogr. p. 190. Urceolaria, Ach. — ß. bryophila, Ach.; cr. rugose; apoth. smaller, disk emergent, urceolate, with a contracted mouth, thalline margin subevanescent. Fr. 1. c. Gyalecta, Ach.

Rocks, stones, dead wood, trunks, and on the earth; New England. - incrusting mosses; Pennsylvania, Muhl. Arctic America, Rich.

X. THELOTREMA, Ach.

Apothecia subconical-truncate, at length open, urceolate-scutelliform; a discrete, lax, membranaceous, lacerate-dehiscent, interior exciple veiling a rigescent disk. Thallus crustaceous.

T. lepadinum, Ach. Disk blackish, at first cæsious-pruinose. Fr. Lichenogr. p. 428. Schar.! Spicil. p. 67.

Trunks, somewhat rare; New England. Arctic America, Rich. (Herb. Hook.!). Our Lichen, as well as that of Arctic America, agrees with the European; and the species is found also in Brazil (Eschwei ler).

XI. GYALECTA, Ach., Fr.

Apothecia orbiculate, urceolate, at first closed, then variously dehiscent, the elevated, discrete, colored border of the exciple surrounding the disk. Disk at first included, like a nucleus, and gelatinous, becoming at length open, explanate, indurated. Thallus horizontal, crustaceous, somewhat tartareous.

G. cupularis, Schær. Apothecia radiate-dehiscent, urceolate-open; border orbicular, elevated, tumid, pale, disk pale-flesh-colored. Fr. Lichenogr. p. 195.

Rocks (especially limestone and sandstone, Fr.) and on the earth. New York, Halsey. Pennsylvania, Muhl.

Apothecia placed upon a thalline stratum, which forms a more or less evident, evanescent (spurious) thalline margin, becoming plane, with an obscure proper margin, and at length cephaloid and immarginate, solid. Thallus vertical, caulescent, mostly solid (podetia), supporting a horizontal, squamulose-granulose thallus, and arising sometimes from a horizontal, adnate, granulose thallus.

The apothecia are often quite those of Parmelia, but they also occur subimmarginate from the first, or with only an obscure proper margin, as observed by Scherer and Eschweiler, and the genus seems properly nearest to Biatora, and related through this to Lecidea. In this view, Cladonia must be taken for the highest type of Lecideaceæ; and the fistulous podetium, analogous certainly (Fr. Lich. p. 14) to the tubulose thallus of some Cetrariæ, and in Cladonia turgida, if I am not mistaken, evidently formed by constriction of the ascending foliaceous thallus of that species, must be considered as indicating a higher rank than the solid podetium; this last being rather a branched stipe, as is suggested by a comparison of Stereocaulon Fibula with Biatora Byssoides. And, adopting a somewhat wider sense for Eschweiler's remark, that Cladonia unites in itself the horizontal and the vertical thallus, we might, in the point of view that we have chosen, see reason to agree with him that this genus is even the highest development of Lichenose vegetation; or to venture, at least, the suggestion, that no genus, which does not include the horizontal type, should seem to be the most perfect typical representative of Lichenes. Fries, from whose profound conclusions we are far from prepared to depart, attributes indeed to Usnea (1. c. pp. 9, 17, 198) the highest rank, and, where he considers the genera as falling into parallel series, he, in this view, assigns the position to Usnea, Stereocaulon, and Sphærophoron. But if there is evidently a distinction between the highest typical development and the highest actually attainable development, and the former represent the most perfect condition of the plant, or genus, per se, as a distinct real or assumed existence in nature, as the latter is representative of extreme tendencies of the vegetation in question to ascend to a higher than its typical structure,- Usnea, &c., may be taken as representing

--

the extreme development of Lichenes, and Cladonia, or some other genus expressing the horizontal type, as representing their typical perfection. S. ramulosum, Ach., a mostly tropical species, with densely fibrillose podetia, and terminal, subglobose apothecia, inhabits North America, according to Acharius and Muhlenberg; but it is probable, only the southern part.

SECT. I. Podetia solid, filamentous within; apothecia normally fus

cous.

* Squamules foliaceous, or fibrillose.

1. S. tomentosum, Fr. Podetia lax, terete, very much branched and the branches somewhat recurved, clothed with a dense, whitish, spongy tomentum ; squamules somewhat rounded, incised-crenate (becoming phylloid-granulose), cinereous-cæsious; apothecia minute, lateral, at length globose. Fr. Lichenogr. p. 201.

On the earth and stones in the lower regions of the White Mountains, and ascending; fertile. Northward to Arctic America, Herb. Hook.!

2. S. corallinum, Fr. Podetia lax, a little compressed, very much branched, glabrous (many conjoined at the base into a dense, at first digitate-divergent sod);' squamules fibrillose, somewhat digitate-ramose, cinereous-cæsious; apoth. scattered or conglomerate (rather large), finally globose. Fr. Lichenogr. p. 201. S. dactylophyllum, Floerk.! Stones, in the lower regions of the White Mountains; fertile.

3. S. paschale, Laur. Podetia lax, rather slender, somewhat compressed, very much branched, subglabrous (many commonly crowded thickly together, but not cæspitose-conjoined); squamules phylloidgranulose, crenate, conglomerate, glaucous; apoth. subterminal, dilated, plane. Fr. Lichenogr. p. 202. S. paschale, Ach. part. Lichen paschalis, L. fide Fr.

Stones, and on the earth in large patches, in the lower regions of the White Mountains; and ascending to alpine districts. Common also on the coast; but the genus is peculiarly montane. The present species was formerly considered as including most of those here described, and the following stations are therefore so far uncertain. New York, Torrey. Pennsylvania, Muhl. Northward to Canada, Michaux; Newfoundland, Pylaie; the Saskatchawan, &c., Rich.; Greenland, Gieseke; and Melville Island, R. Br.

4. S. condensatum, Laur. Podetia erect, terete, scarcely branched, clothed with a thin, white-incarnate tomentum; squamules roundish, teretish, or confluent, glaucous; apoth. terminal, dilated, plane, subpeltate. Fr. Lichenogr. p. 203. S. Meissnerianum, Floerk.!

Stones and rocks, in the lower regions of the White Mountains; somewhat rarely fertile. Occurring also in the deliquescent, degenerate state called by Acharius S. Cereolus (Meth. t. 7, p. 1). The horizontal thallus at the base is persistent, and often conspicuous.

** Squamules verrucæ form, rounded, or angulate.

spar

5. S. denudatum, Floerk. Podetia erectish, terete, terete, somewhat ingly branched above, below denudate, glabrous; granules roundish, thick, cinerascent, at length almost plane, crenate-lobate; apoth. lateral, minute, somewhat plane. Floerk.! D. Lich. p. 13. Fr. Lichenogr. p. 204. S. glaucescens, Tuckerm. Lich. N. E. 1. c.

Rocks; from Greenland, Dill., to New England, where it is common in mountainous, and ascends to subalpine districts. Southward to Pennsylvania, Dill.

6. S. nanum, Ach. Podetia erect, slender, fastigiate-ramose, below denudate, above very finely pulverulent; granules verrucæform, minute, greenish-pallescent, floccose; apoth. small, lateral, convex. Fr.! Lichenogr. p. 205.

Fissures of rocks, and on stones, in the lower regions of the White Mountains; fertile.

Sect. II. PILOPHORON, Tuckerm. Podetia cartilagineous-subfilamentous, or araneous-fistulous within; apothecia subimmarginate, black.

7. S. Fibula, Tuckerm. Crust persistent, appressed, subsquamaceous-granulate, bright green; podetia (solid), erect, terete, simple, somewhat corticate with the green squamaceous granules, at length subdenudate, glabrous; apoth. (lateral, minute, somewhat plane, subimmarginate, and) terminal, mostly solitary, at first depressed-globose, immarginate, at length rather inflated, dark-greenish-nigrescent becoming black.

Moist rocks along streams in mountain forests; White Mountains. Rugose, nigrescent cephalodia (certainly abortive apothecia) occur commonly in the crust, resembling similar ones in S. condensatum. Barren podetia terminated often with powdery green pulvinules, as in S. Cereolus, Ach. Apothecia solid, as in the next, the disk placed upon