ulate-verrucose and somewhat plicate, glaucescent; hypoth. pale; apoth. elevated-subpedicellate on a thalline stratum, which constitutes a thick, subcrenulate, at length evanescent spurious margin; disk plane, delicately pruinate, at length convex, and excluding its thin, elevated, proper margin, from pale flesh-colored becoming blackishfuscous.

Trunks in the mountainous districts of Northern New England, common. Apothecia at first closed, and either sessile (when some states resemble Parmelia carneo-lutea, Turn.) or elevated on a protuberant thalline stratum, at length lacerate-dehiscent and becoming plane, with a thick, crenulate thalline margin, which disappears, leaving the marginate disk. It has often all the aspect of a Parmelia, not a little resembling P. rubra. Is the structure of the apothecia in the last-mentioned species, and in P. carneo-lutea, wholly diverse from the structure above described of the present?

20. B. russula, Tuckerm. Cr. subcartilagineous, rimose-areolate, and granulate, glaucescent (often greenish-sorediiferous); apoth. elevated on a thalline stratum which constitutes a thick, mostly entire spurious margin, becoming convex, and excluding the obscure proper margin, fuscous-reddish. Lecidea, Ach. Syn. p. 40. Lecanora, Feé, Crypt. Exot. p. 116.

Trunks of cedars on the coast of New England. Pennsylvania, Muhl. Extending to the tropics.

21. B. rivulosa, Fr. Cr. tartareous, mouse-colored and paler, covering a fuscous-black hypothallus, which often decussates the crust; apoth. produced from the crust, from pale-fuscous becoming blackish, whitish within, with a thin margin. Fr. Lichenogr. p. 271. Lecidea, Ach. Lecanora falsaria, Ach.

Rocks, especially in mountainous districts; New England. Pennsylvania, Muhl. Northward to Arctic America, Rich.

22. B. exigua, Chaub. Cr. of minute, confluent granules, smooth, cartilagineous, cinereous-greenish; decussated by lines of the black hypothallus; apoth. submarginate, from pale-yellowish becoming fuscous. Fr. Lichenogr. p. 278. Lecidea varians, Ach. Syn. p. 38. Tuckerm. Lich. N. E. 1. c. L. versicolor, Schwein. in Hals. Lich. N. Y. l. c.?

Smooth bark; New England. New York, Halsey? Pennsylvania, Muhl.

23. B. quernea, Fr. Cr. deliquescent, granulose-farinose, fuscescentochroleucous; hypoth. black; apoth. immersed, convex, brown, at length immarginate. Fr. Lichenogr. p. 279. Lecidea, Ach.

Trunks; New England.

24. B. lucida, Fr. Cr. granulate, greenish-yellow, at length deliquescent and ochroleucous; hypoth. white; apoth. (minute), convex, pale yellow, often excluding the paler margin. Fr. Lichenogr. p. 279. Lecidea, Ach.

Stones and decaying wood. Arctic America, Rich.

25. B. aurantiaca, Fr. Cr. cartilagineous, uneven, somewhat granulate, lutescent; innate in a black hypothallus; apoth. somewhat elevated on a thalline stratum which constitutes a crenulate, evanescent, spurious margin, disk dark-orange (and fuscescent), with a thin proper margin. Parmelia, Fr.! Lichenogr. p. 165. Lecidea, Ach. Borr. in Hook. Br. Fl. 2, p. 186. Lecanora salicina, Ach.

Trunks, dead wood, and rocks; New England. New York, Halsey. Pennsylvania, Muhl. Arctic America, Rich.

26. B. fusco-lutea, Hook. (sub Lecid.). Cr. thin, effuse, smooth, somewhat granulose, whitish; apoth. somewhat elevated, plane, yellowish, at length rufous-fuscous, pruinose, with a thin margin. Lecidea, Hook. in Rich. l. c. Lichen fusco-luteus, Dicks. E. Bot. t. 1007.

Upon mosses; Arctic America, Rich. Fries suspects this to be a state of B. ferruginea. It does not seem to be the Lecidea fusco-lutea, a, of Ach. Syn.

XVI. LECIDEA, Ach., Fr.

Apothecia margined at first by a very black, carbonaceous, proper exciple, becoming scutelliform or hemispherical, solid. Disk at first punctiform-impressed, always open, oftener horny, and placed upon a carbonaceous stratum. Thallus horizontal, arising from a hypothallus, somewhat crustaceous, effigurate, or uniform. Apothecia very black from the first, the margin never, and the disk rarely, otherwise colored. Fr.

SECT. I. Thallus effigurate at the circumference, or wholly rugose

plicate.

1. L. candida, Àch. Crust rugose-plicate, candicant, becoming at length white-farinose, lobed at the circumference; hypothallus black;

apothecia appressed, obtusely marginate, glaucous-pruinose, white within. Fr. Lichenogr. p. 285.

On the earth upon mosses; Arctic America, Rich.

2. L. vesicularis, Ach. Cr. bullate-plicate, somewhat caulescent, from greenish becoming glaucous, radiculose at the base; apoth. free, peltate, obtusely marginate, at first pruinose, finally convex, naked; white within. Fr. Lichenogr. p. 286.

On the earth in alpine districts; Arctic America, Rich.

3. L. Wahlenbergii, Ach. Cr. suborbicular, gyrose-plicate, roundlobed at the circumference, from green becoming bright-yellow; hypoth. black; apoth. arising between the areolæ, obsoletely marginate, naked, black within.' Fr.! Lichenogr. p. 291. IcoN, Laur. in Sturm's Fl. t. 28.

Moist sides and crevices of rocks in alpine districts. On the Great Haystack, New Hampshire, infertile. Arctic America, Rich.

4. L. flavo-virescens, Fr. Cr. determinate, areolate-appressed, plicate, lobulate at the circumference, from greenish becoming yellow; apoth. adnate, with a thin margin, becoming at length convex, and excluding the margin, black within. Fr. Lichenogr. p. 291. L. scabrosa, Ach. Meth.

On the earth in mountainous districts, often in company with Biatora Byssoides; White Mountains. According to Borrer (in Hook. Br. Fl. 2, p. 178), L. citrinella, Ach., is the true Lichen flavo-virescens of Dickson, and the present species should bear the name given it by Acharius. Compare Fries, 1. c.

SECT. II. Thallus effuse, uniform.

Subsect. I. AREOLATE, Fr. Crust innate, originally areolate or becoming so. Hypothallus black.

*Saxicola.

5. L. albo-cærulescens, Fr. Cr. at first contiguous, from bluish becoming whitish; apoth. produced from the crust, margin of the annular exciple thin, disk waxy, black, cerulescent-pruinose, white within. Fr. Lichenogr. p. 295. L. pruinosa, Ach. Tuckerm. Lich. N. E. 1. c. -B. immersa, Fr. ; cr. very thin, whitish, disappearing; apoth. small, oftener immersed in the rock. Fr. l. c. L. immersa, Ach.

Rocks and stones, especially granite and mica-slate; New England.

.

New York, Halsey. Pennsylvania, Muhl.- ß, limestone; New York, Torrey. Pennsylvania, Muhl.

6. L. contigua, Fr. Cr. at first contiguous, glaucous-white; apoth. produced from the crust; disk thick, horny, very black, at first glaucouspruinose, with a thick, discrete, plano-cupular, obtusely marginate, carbonaceous exciple. Fr. Lichenogr. p. 298.

Rocks and stones (granite), and often tinged ochraceous by the oxide of iron, in the mountains of New England.

7. L. variegata, Fr. Cr. at length areolate, glaucescent; the black, somewhat fimbriate hypothallus here and there prominent; apoth. produced from the crust, depressed, at first and often persistently glaucouspruinose, black within; disk from urceolate becoming explanate, and dilated, with a persistent, at first thin, coarctate, at length obtusish margin. Fr. Lichenogr. p. 303.

Maritime granite rocks; Arctic America, Fries.

8. L. lapicida, Ach. Cr. at length areolate-verrucose, from glaucous becoming cinereous-white; apoth. superficial, produced from the cortical layer, sessile, not pruinose, horny and cinerascent-black within, with an even, naked disk, and a thin, at length flexuous margin (or, the margin disappearing, finally confluent and irregular). Fr. Lichenogr. p. 306.

Rocks and stones (granite), in mountainous districts; New England. New York, Halsey. Pennsylvania, Muhl. Arctic America, Rich.

9. L. atro-alba, Ach. Cr. somewhat areolate (the areolæ commonly discrete, verrucæform), opake, fuscous, and grayish-white; apoth. produced from the hypothallus, (small,) the obtuse margin scarcely discrete from the naked, at length somewhat umbonate disk. Fr. Lichenogr. p. 310.

Rocks and stones (granite); New England. New York, Halsey. The crust variable, and often nearly obsolete.

10. L. panæola, Ach., Fr. Areolæ of the crust verrucose, gray, variegated with rufescent tubercles; apoth. produced from the hypothallus; exciple cupular, with a persistent, obtuse margin; disk always plane, very black, cæsious-pruinose, white within. Fr. Lichenogr. p. 314. B. obscurata, Fr. ; areola thinner, applanate, somewhat contiguous, fuscescent. Fr. 1. c. L. obscurata, Schar.! Spicil. p. 130. Tuckerm. Lich. N. E. 1. c.

Rocks and stones in mountainous districts; White Mountains.

11. L. fusco-atra, Fr. Areola of the crust cartilagineous, applanate, olivaceous-fuscescent and fuscous, angulate, smooth and somewhat polished (or becoming dull and pallescent); apoth. produced from the hypothallus, appressed; disk plane, at first cinereous-pruinose, at length naked, with a thin, somewhat acute, at length flexuous margin; but the margin disappearing with age, and the apothecia often finally heaped and conglomerate. Fr. Lichenogr. p. 316. L. fumosa, Ach. L. athrocarpa, Ach.

Rocks and stones in mountainous districts. New England. New York, Halsey. Arctic America, Rich.

12. L. confluens, Schær. Cr. rimose-areolate, opake, cinerascentsmoke-colored; apoth. produced from the crust, appressed, somewhat contiguous (often confluent); margin not elevated, obtusish; disk always naked, very black, within cinerascent. Schar.! Spicil. p. 144. Fr. Lichenogr. p. 318.

Rocks and stones in mountainous and alpine districts; New England. New York, Halsey. Arctic America, Rich., Hook.

13. L. Morio, Schær. Areolæ of the crust verrucose, shining, of a yellowish-copper-color, radiant at the circumference; apoth. produced from the thick, determinate, black hypothallus, minute, depressed, plane, becoming gyrose-plicate with age; margin thin; disk always naked, black within. Fr. Lichenogr. p. 319. Schær. Spicil. p. 133.— B. coracina, Schær. ; crust (from the predominance of the hypothallus) cinerascent-black. Schar.! 1. c. Fr. 1. c.

Rocks in alpine and subalpine districts; White Mountains.

14. L. geographica, Schær. Cr. of somewhat confluent, bright-yellow areola; apoth. produced from the hypothallus, blackish within; margin of the cupular exciple thin; disk naked. Fr. Lichenogr. p. 326. Schar.! Spicil. p. 124. — a. atro-virens, Schær.; areolæ verrucæform, scattered in the hypothallus; apoth. immixed. Fr. 1. c. Schær. l. c.— B. contigua, Schær. ; areolæ applanate, confluent in a somewhat contiguous, chinky crust; apoth. immersed. Fr. l. c. Schær. l. c.—y. alpicola, Schær. ; areolæ applanate, coalescent and large, somewhat rugose, interruptedly covering the hypothallus; apoth. innate. Fr. 1. c. Schær. l. c.

Rocks and stones (granite and mica-slate), in alpine and subalpine districts, and at lower elevations, in the mountains of New England. Newfoundland, Pylaie. Northward to Arctic America, Rich.