23. SPHÆROPHORON. Apothecia terminal, spherical; nucleus black, dehiscent.

Tribe II. ENDOCARPACEÆ, Fr. - Apothecia immersed in the thallus, globose, the thalline exciple attenuated into a neck, and terminated by a discrete heterogeneous papillæ form ostiole. Nucleus deliquescent. Thallus horizontal, foliaceous or crus

taceous.

24. ENDOCARPON. Apothecia pale, included in the foliaceous thallus. 25. SAGEDIA. Apothecia blackish, immersed in the crustaceous thallus. 26. PERTUSARIA. Apothecia verrucæform, with one or more blackish, papillate ostioles.

Tribe III.

VERRUCARIACEÆ, Fr. - Apothecia rounded, a closed proper exciple (perithecium) becoming pertuse with an ostiole, or at length open. Nucleus gelatinous, subhyaline, deliquescent. Thallus crustaceous.

27. CONOTREMA. Perithecia at length open; nucleus subdisciform. 28. VERRUCARIA. Perithecia closed, with a papillæ form or simply pertuse ostiole.

Tribe IV. LIMBORIACEÆ, Fr.- Apothecia rounded, the carbonaceous proper exciple closed, at length variously dehiscent. Nucleus subceraceous, rigescent. Thallus crustaceous. 29. PYRENOTHEA. Perithecia at length pertuse, protruding the fatiscent nucleus.

I. USNEA, Dill., Hoffm.

Apothecia rounded, peltate, subterminal; disk open, placed upon the filamentous medullary stratum, the margin mostly radiate-ciliate. Thallus cartilagineous, at first erect, suffruticulose, becoming with age more or less filamentous or pendulous, the crustaceous cortical stratum somewhat separate from the medullary.

A genus universally diffused; and the first species occurring, in one or other of its forms, in every quarter of the globe. This species extends throughout the United States. U. homalea, Tuckerm. Enum. 1845, with a softish, much compressed, ancipital, rugulose, fastigiate and attenuate-branched thallus, and plane apothecia, with scarcely elevated, obtuse margins, Ramalina homalea, Ach. Lich. p. 598, was discovered on the coast of California by Menzies! but has not been detected elsewhere.

1. U. barbata, Fr. Thallus terete, irregularly branched, at length annulate-cracked, glaucous; apothecia almost immarginate, radiate, disk pale. Fr. Lichenogr. p. 18.a. florida, Fr., very much branched, somewhat scabrous, apoth. large. U. florida, Ach. - 3. strigosa, Ach., rather small, very thickly fibrillose-strigose. Ach. Syn. p. 305. — y. rubiginea, Michx., lax, scabrous, more or less rusty-red. U. florida, var. rubiginea, Michx. Fl. 2, p. 332. — d. hirta, very much branched, dwarfish, the fibrillæ somewhat elongated, oftener verrucose-pulverulent. U. hirta, Hoffm.-s. plicata, Fr., pendulous, elongated, subdichotomous, entangled, lax, smoothish, pale. U. plicata, Ach.. dasypoga, Fr., pendulous, elongated, branches somewhat simple, lateral fibres spreading. U. barbata, Hoffm. Lichen barbatus, L.

Very common; a, ß, ε, and 5 mostly on trees, the last two less frequently fertile; on rails, sterile; New England. New York, Torrey. Pennsylvania, Muhl. Northward to Arctic America, Richardson (Franklin's Narrative, App.).

2. U. longissima, Ach. Th. pendulous, filamentous, terete-compressed, somewhat rugulose, smoothish, nearly simple, pale glaucous, with approximate, horizontal, at length tortuous fibres. Ach. Syn. p. 307.

Firs and other trees on the sides, and in swamps at the base, of the high mountains of New England, and northward, occurring 5 feet long. Infertile, as is also the case with the European Lichen on which the species was founded. It seems, like the last species, to be very widely diffused; and I have, or have seen, specimens probably belonging to it, from Europe, Asia, Africa, and New Holland. A single Cape of Good Hope specimen, in my possession, is fertile, and has quite concave radiate apothecia, with somewhat elevated, obtuse margins. The earliest specimen I have seen is an infertile one in the Berlin herbarium, collected in Cappadocia by Tournefort.

3. U. angulata, Ach. Th. pendulous, flexuous, angular, nearly simple, pale cinerascent; angles acute, scabrous; fibres horizontal approximated, simple, short, terete-attenuate. Ach. Syn. p. 307. Halsey, Lich. New York, in Ann. Lyc. 1, p. 21.

Trees, Pennsylvania, Muhl., Ach. New York, Torrey. Massachusetts, occurring 4 feet long, Halsey. Spruce swamps, Chelmsford, Russell!

4. U. trichodea, Ach. Th. pendulous (prostrate), very delicate

and flexile, filiform, smooth, somewhat branched, whitish-pallescent; fibres horizontal, scattered, rather secund, flexuous; apoth. small, with an elevated, thin, entire margin. Ach. Syn. p. 307. Icon, Ach. Meth., t. 8, f. 1.

Nova Scotia, Menzies, fide Ach. Canada, Herb. Michaux! The specimen in herb. Floerk.! which Floerke supposed might be U. trichodea, Ach., is referred by him to U. plicata.

5. U. sphacelata, R. Br. Th. erectish, fruticulose, the principal branches ochroleucous, black-vittate, smooth, the ultimate ones attenuate, black, all sorediiferous. R. Br. Suppl. to Parry's Voy. p. 307.

Melville Island, R. Br. I have not seen American specimens, but I have received fine ones from Dr. Vahl, collected by him in Spitzbergen.

II. EVERNIA, Ach., Fr.

Apothecia rounded, scutelliform, marginal; disk open, placed upon the cottony medullary layer, colored. Thallus originally erect, teretish-fruticulose or compressed-foliaceous (abnormally filamentous or pendulous), within uniform, and either fistulous, or filled with the cottony medullary layer.

The third section of this genus (Physcia) is further represented in the South of Europe by three species not as yet known with us:— E. intricata, Fr., with a much-branched, linear, glaucous thallus; E. villosa, Fr., with a villous, multifid, glaucous thallus; and E. flavicans, Fr, with a much branched, linear, bright yellow thallus; of which the first and last species attain to the southern coast of England (Borrer); the first two are found in the Canary Islands (Montagne); the second in Peru (Acharius); and the last in the West Indies (Ach.) and South America (Eschweiler). It is possible that one or more of these species may occur in the Southern States. In the North, E. divaricata, Ach., nearest to E. prunastri, with a more or less filamentous, softish, lacunose thallus, is the only European Lichen of the present section that is wanting with us.

§ I. Cornicularia, Fr. Fruticulose, passing into filamentous or pendulous forms.

1. E. furcellata, Fr., with long (terete-compressed?) di-trichotomously divided, suberect, entangled branches, from hoary becoming cinereous, or slightly greenish, with furcate fuscous apices, Dill. Musc. t. 85,

f. 14, was constituted on a Lichen which Fries referred to this figure and description of Dillenius, whose own specimens were sent him from Pennsylvania, by J. Bartram. I have not seen Fries's description, but he says incidentally (Lichenogr. p. 478) that his specimens are (like those of Dillenius) infertile, and that the genus of the Lichen is therefore doubtful.

2. E. jubata, Fr. Thallus terete, smooth, much branched, blackfuscous (or palish), apices simple; apothecia innate-sessile, entire, of the same color with the thallus. Fr. Lichenogr. p. 20. - a. bicolor, Fr.; th. erectish, fruticulose, branches divergent, apices cinereousfuscescent. Cornicularia bicolor, Ach.— ß. chalybeiformis, Ach.; th. subfilamentous, decumbent, somewhat rigid, divergent (often whitesorediiferous), apices oftener palish. Alectoria jubata, var. chalyb., Ach. Cornicularia fibrillosa, Halsey, Lich. N. Y. 1. c. non Ach. ―y. implexa, Fr.; th. filamentous, pendulous, very much branched, entangled, softish, apices of the same color. Lichen jubatus, L. — 8. setacea, Ach.; th. filamentous, rather slender, very long, pendulous, somewhat simple, frequently sorediiferous. Alect. jubata, var. setacea, Ach. Setaria trichodes, Michx. Alect. trichodes, Pylaie Voy. p. 17.

Very common a, trees on high mountains, fertile; and on the ground in alpine districts, infertile; White Mountains. Arctic America, R. Br. (Ross's Voy.).—ß, old rails, stones, and trees, sterile; common in New England. Arctic America, R. Br. (Scoresby's Arc. Regions), Rich.y, trees in mountainous and subalpine districts, infertile; New England and westward. Arctic America, Rich. 8, dead wood, Canada, Michaux! Newfoundland and northward, Herb. Hook. ! Michaux's Lichen is extremely delicate, but apparently not distinct.

3. E. divergens, Fr. Th. somewhat angular, dark-chestnut, whitedotted; branches elongated, flexuous; apices attenuated, forked, of the same color; apoth. innate-sessile, crenulate, disk of the same color. Fr. Lichenogr. p. 21. Cornicularia, Ach.

On the earth, alpine and arctic regions. Newfoundland, Herb. Delessert. Bear Lake, Rich., Hook. ! (Parry's Sec. Voy.).

4. E. ochroleuca, Fr. Th. teretish, smoothish, ochroleucous (and palish), axils compressed-sublacunose, irregularly branched, apices attenuate, subfibrillose; apoth. innate-sessile, at length repand, disk lividfuscous. Fr. Lichenogr. p. 22.-a. rigida, Fr.; th. suberect, fruticulose, rigid, ochroleucous, apices reflexed, blackish. Cornic, ochro

leuca, Ach.-B. sarmentosa, Fr. ; th. filamentous, sarmentose-pendulous, much branched, softish, ochroleucous or pale, apices elongated, of the same color. Alectoria sarmentosa, Ach.

Mountainous, alpine, and arctic regions. -a, on the earth; White Mountains, infertile. Arctic America, Rich. (Herb. Hook. !), R. Br. (Parry's First Voy.), fertile. — ß, on the trunks and branches of trees in the mountains of New England, and northward, fertile; and on the earth, alpine and arctic, sterile. a does not seem to be well represented on our mountains. The arctic specimens are very fine.

5. E. vulpina, Ach. Th. much branched, rigid, angular, compressed-lacunose, greenish-yellow; apoth. sessile, disk fuscous. Fr. Lichenogr. p. 23.

Trunks and rails, N. W. America, Menzies! and Rocky Mountains, Herb. Hook. fertile. A few specimens in my possession, from the White Mountains, and elsewhere, may belong to this; but most of the degenerate plants commonly referred to it here are, perhaps, as safely placed with E. prunastri.

II. Dufourea, Fr. Fruticulose, inflated, apothecia terminal.

6. E. ramulosa, Hook. (sub Dufourea). Th. cæspitose, terete-compressed, scarcely lacunose, fuscous-glaucescent, much branched and fuscous-olivaceous above, branches subdichotomous, tuberculate-ramulose, obtusish. Dufourea ramulosa, Hook. App. to Parry's Sec. Voy. p. 424.

Arctic America, Hook. Considered by Hooker nearest to E. madreporiformis, from which he remarks that it differs in color, in its branching, and in being fistulous.

7. E. arctica, Rich. (sub Dufourea). Th. somewhat cæspitose, subsimple, or with a few short branches above, subulate-ventricose, smooth, sulphureous becoming brownish; apoth. chestnut, with an obscure, crenulate thalline margin. Dufourea arctica, Rich. in Frankl. Narr. p. 762 & ICON, t. 31.

Bear Lake, and elsewhere in Arctic America, Rich. (herb. Hook.!). I follow Fries in considering the Dufoureæ a section of the present genus. Hooker (App. to Parry's Sec. Voy. 1. c.) refers Dufourea nodosa, R. Br. (Ross's Voyage), to a variety of the present species. I have not seen the description of Brown.

III. Physcia, Fr. Foliaceous-compressed, the under side channelled.