is perhaps referable to this species, which has escaped notice, but probably occurs within our limits.

8. U. hirsuta, Ach. (sub Gyroph.). Th. coriaceous, softish, pulverulent, cinerascent and white; on the under side from pale-fuscous becoming blackish, very hirsute with large, softish, at first pale, branched fibres (at length subfibrillose-scabrous and black); apoth. marginal, appressed, becoming patellæform, and at length convex, and subglobose, gyrose-plicate, with a thin margin. Gyrophora hirsuta, Ach.! Syn. p. 69. U. vellea, y. hirsuta, Fr. Lichenogr. p. 358. — ß. depressa; th. at length rigid; apoth. somewhat impressed, plane, with a thick margin. U. vellea, B. depressa, Fr. l. c. U. depressa, B. spadochroa, Schar.! Tuckerm. Lich. N. E. 1. c. (sub Gyroph. spadochroa).

Rocks. Common in mountainous, and ascending to alpine districts, New England, fertile. Northward to Arctic America, R. Br. The New England Lichen does not appear to differ from those of Sweden and Switzerland, unless, perhaps, in attaining to a larger size, and, like the foreign ones, is near the U. vellea of Sweden, which differs in its tumid-marginate, papillate apothecia. Of the last species I have not seen American specimens, unless, with Scherer, and in accordance also with the earlier view of Fries, we consider the present species as a variety of it.

9. U. Dillenii, Tuckerm. Th. coriaceous, rather rigid, smooth, from glaucous-fuscescent becoming dark-fuscous; on the under side black, and closely hirsute with short, black, crowded fibres (or lacerate, and papillose-scabrous); apoth. convex, at first orbiculate and concentrically plicate, becoming at length lirellate, with a thin (canaliculate) margin. Lichenoides coriaceum latissimo folio, &c., Dill. Musc. p. 545, & t. 82, f. 5. U. vellea, Michx.! Fl. 2, p. 323, & Auct. Amer.

Rocks. Paiqualian Mountain, New Jersey, J. Bartram (Dill.). Canada, Michaux! Newfoundland, Herb. Montagne! Pennsylvania ! Muhl. New York, Torrey. Very common in New England, and fertile. The apothecia are often abortive (very small, and forming sometimes a continuous black crust); but in a single specimen from the White Mountains they are perfect, and agree with the minute description in Michaux, whose Lichen was certainly the same with that of Dillenius. The species is widely diffused in North America, and preserves its peculiar features from Newfoundland to the Alleghanies of Pennsylvania; contrasting in this respect with the more limited and

northern U. hirsuta. It was considered certainly distinct, in 1841, by Montagne. Linnæus cites the figure of Dillenius under his Lichen velleus, and his description includes also U. hirsuta, the differences in the apothecia being disregarded; but the specimen that I saw in the Linnæan herbarium was the L. vellea of Sweden, which I have collected abundantly in that country, and which seems to me very distinct from the present.

Sect. II. LIRELLATE. Apothecia somewhat lirellæ form, becoming at length angulate-patellate, or finally crowded together in a hemispherical, subimmarginate, lirellate tubercle.

10. U. hyperborea, Hoffm. Th. coriaceous-membranaceous, papulose-rugose, dark-olivaceous-fuscous, and blackish; on the under side lacunose, smooth, and fuscous-nigrescent; apoth. appressed, originally somewhat lirellæ form, at length angular, substellate-multiform, plicate and papillate, with an apparent margin. Fr. Lichenogr. p. 353. Gyrophora, Ach. Floerk.! Berl. Mag. cit. Fr.

Alpine and subalpine rocks (and perhaps a flocculose state, ß. deusta, Enum. Lich. N. Amer., descending), White Mountains; Chin of Mansfield and other of the Green Mountains, fertile. Arctic America, Rich. Rocky Mountains, Herb. Hook.! In separating this section of the genus from the other, I have endeavoured to indicate the features of difference that seem, at the first view, to distinguish the lirellate from the patellate apothecia; but I am uncertain how far the proposed characters are constant. The ternary division, incidentally proposed by Fries (Lichenogr. p. 349), suggested the present; but my present acquaintance with the species has not enabled me to adopt the former entire.

11. U. erosa, Hoffm. Th. cartilagineous, rigid, cribrose-reticulate, at length rugulose, dark-fuscous-nigrescent; on the under side papillose-granulate, subfibrillose-lacerate in somewhat anastomosing ridges, dark-fuscous and cinerascent; apoth. originally somewhat lirellæform, at length patellate, becoming convex and gyrose-plicate, and finally substellate-multiform, and immarginate. Fr. Lichenogr. p. 354. Schær. ! Spicil. p. 93.

Alpine rocks. White Mountains, fertile. Northward to Arctic America, R. Br., Hook.

zies!

Newfoundland, Pylaie.
Northwest Coast, Men-

12. U. Muhlenbergii, Ach. (sub Gyroph.). Th. coriaceous-cartilagineous, somewhat lacunose-reticulate, olivaceous-fuscous; on the under side papillose-granulate, lacerate in anastomosing ridges, fuscouscinerascent; apoth. somewhat sunk, originally lirellaform, at length composite, stellate-multiform, crowded finally into a convex, immarginate tubercle. Gyrophora, Ach. Lichenogr. p. 227. Syn. p. 67. Hook. in Rich. l. c. p. 758. — ß. alpina, Tuckerm.; smaller, thickened, and complicated. Lich. N. E. 1. c.

Rocks. Lancaster, Pennsylvania, Muhl.! New York, Halsey. New England, common and luxuriant on the coast. Northward to Newfoundland, Bory in herb. Kunth! and Arctic America, Rich. — ß, alpine rocks, White Mountains. The descriptions by Sprengel (Syst. IV. pp. 262, 263) of this species and of U. Pennsylvanica seem to have been transposed.

13. U. angulata, Tuckerm. Th. coriaceous-cartilagineous, very rigid, smooth, and somewhat polished, becoming dark-fuscous and nigrescent; on the under side very black, papillose-granulate, lacerate at the centre, with paler fibres; apoth. somewhat impressed, originally sublirellæ form, becoming angulate-patellate, lirellate, and at length convex, with an obtuse margin.

Rocks. (California, Menzies!)

Northwest Coast, Herb. Hook. ! Perhaps nearest to U. Dillenii, the apothecia at length resembling those of that species.

XVIII. OPEGRAPHA, Humboldt.

Apothecia somewhat lirellæ form, elongated, margined by a free, carbonaceous, proper exciple. Disk canaliculate, at first closed by the inflexed-connivent margin, becoming open, indurated, and horny. Thallus crustaceous.

The Graphidea proper, excluding Umbilicaria, constitute a peculiar subtribe, which attains to its full development only in the tropics; passing there into several genera not found elsewhere. Eschweiler (Systema, & Lich. Brasil. in Mart. Fl. Bras.), Chevallier (Histoire des Graphidées), and Feé (Essai sur les Cryptogames des Écorces Exotiques Officinales) have illustrated these genera, which are probably represented in our Southern States, where also several remarkable species of the present genus, inhabiting the South of Europe and extending north as far as the warmer parts of England (Borrer), may be expected to occur.

SECT. I. Apothecia superficial, destitute of a thalline margin.

1. O. varia, Pers., Fr. Crust somewhat leprous, indeterminate (rarely innate in the matrix); apothecia superficial, tumid; margins of the entire exciple at length distant, becoming thin, or disappearing; disk somewhat plane, åt first subpruinose, blackish within. Fr. Lichenogr. p. 364. O. cymbiformis, Schær. ! Spicil. 1, p. 50. a. pulicaris, Fr.; apoth. rather elliptical; disk a little concave, margin inflexed. Fr. 1. c. O. vulvella, Ach.-B. notha, Fr. ; apoth. rounded; disk turgescent, and often obliterating the margin. Fr. l. c. Opegrapha, Ach. Graphis curvula, Ehrh. Tuckerm. Lich. N. E. l. c.—y. signata, Fr. ; apoth. elongated; disk broad, plane, margin evanescent. Fr. l. c. Opegrapha, Ach. Lichen hebraicus, Hoffm. O. cymbiformis, var. hebraica, Scher.! Spicil. p. 330, part. — 8. diaphora, Fr.; apoth. elongated, both ways rather attenuated; margin somewhat persistent. Fr. 1. c. Opegrapha, Ach.

Thick bark of oaks and other trees, and degenerant on dead bark and wood, and stones; New England. New York (a and 8), Halsey. Pennsylvania (a and 8), Muhl.

2. O. atra, Pers., Duf. Cr. innate in the matrix; apoth. emergentsuperficial, slender, shining, acute; margin of the somewhat entire exciple thin; disk linear, canaliculate, naked, horny within. Fr. Lichenogr. p. 366. — a. stenocarpa, Fr. ; apoth. very long, semicylindrical, flexuous; discrete, or reticulate-anastomosing, or maculæ form and irregular. Fr. 1. c. Schar.! Spicil. p. 48. O. stenocarpa, denigrata, vulgata, & epipasta, a, Ach.—ß. abbreviata, Fr.; apoth. abbreviated, irregular, often radiately disposed. Fr. l. c. O. depressa, & O. epipasta, 7, 8, Ach.—y. macularis, Fr.; apoth. dilated into somewhat radiate, immarginate maculæ, and confluent. Fr. ! l. c. Arthonia astroidea, & A. Swartziana, Ach.-8. siderella, Fr.; cr. fuscescent; apoth. acute, opake, somewhat innate and here and there erumpent. Fr. 1. c. Opegrapha, Ach. O. rufescens, a. rubella, Schær.! Spicil. p. 50 (e Fr.).

Smooth bark of trees; New England. New York (a and y), Halsey. Arctic America (O. epipasta, 8), Rich.

3. O. herpetica, Ach., Fr. Cr. innate in the matrix, at length erumpent, and verruculose; apoth. emergent, elliptical or obtusely lanceolate, opake (somewhat ocellate or marginate by the white thalline verrucæ); margins of the entire exciple thin; disk canaliculate, naked,

horny within, becoming tumid, and covering the margin. Fr.! Lichenogr. p. 368.

Bark of oaks, and other trees, New England.

4. O. abnormis, Ach. Cr. thin, softish, white; apoth. immersed, very slender, short or very long, flexuous, confluent, rugose-crisped, opake, black; disk and margin somewhat confluent and indistinct. Ach. Syn. p. 74.

Hard bark of trees; Pennsylvania, Muhl., Ach. A mostly tropical species growing on Cascarilla, and other bark.

Sect. II. GRAPHIS. Apothecia erumpent, coronate for the most part with a thalline margin.

5. O. scripta, Ach., Schær. Cr. innate in the matrix, becoming at length exposed, uneven, and pulverulent; apoth. immersed, erumpent, with a raised accessory thalline margin; the proper margin tenuescent, smooth; the disk linear, at first cæsious-pruinose. Fr. Lichenogr. p. 370. Schar.! Spicil. p. 46.a. limitata, Schær. ; apoth. emergent, scattered irregularly, various. Fr. 1. c. Schær. 1. c.-B. recta, Schær. ; apoth. immersed, straight, parallel, disk somewhat dilated. Fr. l. c. Schær. 1. c. O. recta, Humb. O. Cerasi & betuligna, Ach. — y. serpentina, Schær.; apoth. immersed, flexuous, very long, the thalline margin tumid, evanescent. Fr. l. c. Schar. 1. c. O. serpentina, Ach. Bark of trees; New England. New York (a, ß, and y), Halsey. Pennsylvania (a and ß), Muhl.

6. O. polymorpha.

Cr. somewhat pulverulent, whitish-cinerascent or very white; apoth. somewhat rounded or oblong, irregular, without apparent proper margin, from plane becoming tumid and elevatedpunctate, angulose, repand, or somewhat stellate-ramulose, cæsiouspruinose, with a more or less conspicuous thalline margin. Arthonia polymorpha, Ach. Syn. p. 7. Feé Crypt. Exot. p. 53. Eschw. Lich. Bras. 1. c. p. 111. O. Cascarilla, Floerk.! herb. (fide ips.).

North America (Pennsylvania ?), Muhl. A common Lichen of Cascarilla bark, which Eschweiler (1. c.) has illustrated at length. The arrangement of Muhlenberg's catalogue leaves it probable that he considered it to occur within our limits.

7. O. inusta, Ach. (sub Graph.). Cr. membranaceous, somewhat rugulose, pale-virescent, decussated by black lines; apoth. minute, immersed, rather short, straight, simple or somewhat stellate-ramose, ob