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expansions, or external to the original thallus, forming new individ. uals of the parent thallus; and 2. by sporidia, consisting of subglobose or elliptical cells, which are either naked or contained in other elongated more or less vertical cells (asci), and immersed in the thalamium (or fructification proper), and propagate new individ uals of the species. The thalamium is either rounded, gelatinouswaxy, and the asci converging (nucleiform); or flattened at length into a rigid, persistent, or afterwards collapsing lamina (subdisciform); or originally disciform (open); and is itself contained in a receptacle (exciple), either of the same color with and like the thallus (thalline exciple), or of different color and nature (proper exciple). The whole fructification constitutes the apothecium, which is typically round, though also occurring normally oblong and linear (lirellaform), and is either excavated with a contracted margin (urceolate); or slightly concave with an elevated margin (scutelliform); or very concave-scutelliform (cyathiform); or very concave-scutelliform and pervious (infundibuliform, a term applied also to the pervious cup-bearing podetia of Cladoniæ); or goblet-shaped and stipitate (crateriform); or dilated, flat, and without prominent margin (peltaform, of which the reniform is a variation); or convex with repressed margin (cephaloid); or between scutelliform and peltæ form (disciform); or between scutelliform and cephaloid (tuberculate). When the thalline exciple is prolonged below into a footstalk, it is said to be pedicellate; a proper exciple in like manner prolonged is said to be stipitate. When the proper exciple is originally and typically closed, the apothecium receives the name of perithecium. In the Angiocarpi several thalamia are sometimes contained in the same exciple (composite apothecia); and in the Gymnocarpi, in like manner, several disks are sometimes confluent (symphycarpeous apothecia). The colors of the thallus in Lichenes are disposed by Fries in four series: 1. from pale green becoming glaucous; 2. from yellowish green becoming ochroleucous ; 3. from dark green becoming fuscous or olivaceous; 4. from pale yellow-green becoming lemon-colored. Each series has its peculiar variations. The glaucous runs into pale green, cerulescent, and white; the fuscous into dark green, olivaceous, cinereous, grayishfuscous, and dark chestnut; the ochroleucous into yellowish green and albescent; the lemon-colored into pale yellow, orange-red, and vermilion-red.

SYNOPSIS OF THE GENERA.

Div. I. GYMNOCARPI, Schrader, Fries.

Apothecia open, disciferous. Thalamium originally disciform, or becoming so, contained in a thalline exciple or a proper exciple; disk normally persistent, ascigerous; sometimes originally pulveraceouscollapsed.

Tribe I. PARMELIACEÆ, Fr.-Apothecia rounded, from con

cave becoming explanate, scutelliform, rarely peltate. Disk somewhat waxy, persistent, contained in a thalline exciple. Subtribe 1. USNEEE, Eschw. - Disk open. Thallus subvertical, or pendulous-sarmentose, centripetal, without apparent hypothallus. 1. USNEA. Apothecia peltate; thallus with a solid medullary layer. 2. EVERNIA. Apothecia scutelliform; thallus fistulous, or with a cottony medullary layer.

3. RAMALINA. Apothecia orbiculate-subpeltate; disk pale, of nearly the same color with the thallus.

4. CETRARIA. Apothecia scutellate-peltate, oblique.

Subtribe 2. PARMELIEE, Eschw. -Disk at first closed, becoming at length discoid-open. Thallus horizontal, centrifugal, with a hypothallus.

5. NEPHROMA. Apothecia reniform, adnate to the under side of the lobes.

6. PELTIGERA. Apothecia peltæ form, adnate to the upper side of the elongated lobes.

7. SOLORINA. Apothecia maculæ form, adnate to the disk of the thallus.

8. STICTA. Apothecia scutelliform; thallus with cyphellæ, or discolored spots, on the under side.

9. PARMELIA. Apothecia scutelliform; thallus without veins or cyphellæ beneath.

10. THELOTREMA. Apothecia urceolate-scutelliform, a discrete interior exciple veiling a rigescent disk.

11. GYALECTA. Apothecia urceolate, an elevated and discrete colored margin bordering a nigrescent disk.

Tribe II. LECIDEACEÆ, Fr. Apothecia rounded, a persistent

disk contained in an open proper exciple, which it finally cov ers, and becomes convex, cephaloid, and immarginate.

12. STEREOCAULON. Apothecia turbinate, at length cephaloid; podetia mostly solid.

13. CLADONIA. Apothecia at length cephaloid, inflated; podetia fistulous.

14. BEOMYCES. Apothecia capitate, globose, immarginate, velate. 15. BIATORA. Apothecia disciform, solid, with a waxy (originally

paler) exciple.

16. LECIDEA. Apothecia disciform, solid, with a carbonaceous, black proper exciple.

Tribe III. GRAPHIDACEE, Fr.-Apothecia of various form, an altered thalline carbonaceous proper exciple, or an originally proper exciple margining a gyrose and proliferous-papillate, or canaliculate disk.

17. UMBILICARIA. Apothecia orbiculate or lirellæ form; thallus folia.

ceous.

18. OPEGRAPHA. Apothecia lirellæ form; thallus crustaceous.

19. LECANACTIS. Apothecia irregular, at first open, with a pruinose thalline veil.

Tribe IV. CALICIACEÆ, Fr.- Apothecia orbiculate or globose, always open, margined by a proper exciple, the disk collaps ing into naked sporidia; or without an exciple, the sporidia capituliform-compact.

20. TRACHYLIA. The carbonaceous exciple innate, with an ascigerous disk.

21. CALICIUM. The carbonaceous exciple free; disk compacted of naked sporidia.

22. CONIOCYBE. Exciple wanting; sporidia capituliform-compact.

Div. II. ANGIOCARPI, Schrader, Fries.

Apothecia closed, nucleiferous, pertuse and with an ostiole, or irregularly dehiscent; the nucleus included, subglobose, ascigerous. Tribe I. SPHÆROPHORACE, Fr.- Apothecia formed of the intumescent apices of the thallus, closed, at length irregularly lacerate-dehiscent. Nucleus subglobose. Thallus vertical, fru

ticulose.

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 papillæform 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. B. 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. — §. hirta, very much branched, dwarfish, the fibrillæ somewhat elongated, oftener verrucose-pulveru. lent. U. hirta, Hoffm.-. 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 mostly on trees, the last two less frequently fertile; 8 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 so:newhat 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. Massachu setts, occurring 4 feet long, Halsey. Spruce swamps, Chelmsford, Russell!

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

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