by Patrica L Hinds and James W Hinds - 2013 edition
BROAD - lobes usually greater than 4 mm
NARROW - lobes usually less than 4 mm
NEITHER - neither sorediate nor isidiate
BROWN - light to dark brown (or greenish brown)
BLACK TO SLATE - black, dark olive-green, or slate gray; gelatinous when wet
FLAT - branches flattened in cross-section
ROUND - branches round in cross-section
TUFTED - stalks much branched, like a bush
PODETIA - stalks unbranched to sparsely branched
R10 Mineral-Gray, Narrow, Sorediate
R11 Mineral-Gray, Narrow, Isidiate
R12 Mineral-Gray, Narrow, Neither
S7 Tufted, White To Light Gray
S9 Podetia, Brown Or No Apothecia, Soredia
S10 Podetia, Brown Or No Apothecia, No Soredia
T7 Mineral-Gray, Broad, Sorediate
T8 Mineral-Gray, Broad, Isidiate
T9 Mineral-Gray, Broad, Neither
T10 Mineral-Gray, Narrow, Hollow
T11 Mineral-Gray, Narrow, Sorediate
T12 Mineral-Gray, Narrow, Isidiate
T13 Mineral-Gray, Narrow, Neither
T17 Yellow-Green, Round, Pendent
1. Soredia or isidia present; apothecia usually absent
2. Thallus closely adherent to rock; central part with laminal, coarse, bulbous isidia, some of which break up into coarse soredia .... Xanthoria sorediata
2. Thallus lobes narrow, dissected, and ascending, 0.1-0.4 mm wide; laminal coarse isidia absent but granular soredia present at lobe margins .... Xanthomendoza weberi
1. Soredia and isidia absent; apothecia usually present
3. Lobes flat, thin, and adherent to substrate, often with thickened edges giving lobe tips a concave appearance .... Xanthoria parietina
3. Lobes appearing thicker, with tips convex and proximal parts arched .... Xanthoria elegans
1. Lobes relatively broad, 3-10 mm wide
2. Soredia on surface of lobes .... Flavoparmelia caperata
2. Isidia on surface of lobes pustulate, sometimes breaking open to appear sorediate .... Flavoparmelia baltimorensis
1. Lobes narrower, 1-3 mm wide
3. With large capitate soralia; alpine .... Arctoparmelia incurva
3. With marginal soralia .... Usnocetraria (Allocetraria) oakesiana
1. Lobes 3-10 mm wide; isidia pustulate, sometimes breaking open to appear sorediate .... Flavoparmelia baltimorensis
1. Lobes 1-3 mm wide; isidia not breaking open
2. Lower surface black with brown only at the margins .... Xanthoparmelia conspersa
2. Lower surface uniformly tan to dark brown .... Xanthoparmelia plittii
1. Lower surface white .... Arctoparmelia centrifuga
1. Lower surface not white
2. Lower surface uniformly tan to dark brown
3. K+ yellow changing to orange-red (stictic and norstictic acid) .... Xanthoparmelia cumberlandia
3. K+ yellow changing to blood red (salazinic acid) .... Xanthoparmelia viriduloumbrina
2. Lower surface black, except brownish at margin
4. K+ yellow changing to orange red (stictic and norstictic acid) .... Xanthoparmelia angustiphylla
4. K+ yellow changing to blood red (salazinic acid) .... Xanthoparmelia hypofuscsa (tasmanica)
(for Peltigera species found on soil over rock, see Soil Key S2)
1. Attached to substrate by single holdfast (umbilicate)
2. Indistinctly umbilicate; small lobes 1.0 cm or less crowded together on wet rocks; upper surface with black dots (perithecia); turns green when wet .... Dermatocarpon luridum
2. Distinctly umbilicate; lobes usually >1.0 cm wide
3. Upper surface with black dots (perithecia); apothecia never found .... Dermatocarpon miniatum
3. Upper surface without black dots (perithecia); apothecia common .... see Rock Key R15; Lasallia, Umbilicaria
1. Attached to substrate by rhizines or tomentum
4. Coarse granular soredia present .... Nephroma parile
4. Nonsorediate
5. Lower surface tomentose
6. Apothecia located on lower surface of lobe tips .... Nephroma resupinatum
6. Apothecia located on upper surface .... Lobaria quercizans
5. Lower surface not tomentose
7. Margins of lobes lobulate to dentate-isidiate .... Nephroma helveticum
7. Margins of lobes entire .... Nephroma bellum
1. Medulla orange-red; soredia coarse, sometimes isidioid .... Phaeophyscia rubropulchra
1. Medulla not orange-red
2. Soralia marginal and isidioid
3. Thallus brownish or greenish mineral-gray; lobes usually 0.5-1.5 mm wide .... Phaeophyscia adiastola
3. Thallus blackish mineral-gray; lobes usually <0.5 mm wide .... Phaeophyscia sciastra
2. Soralia not isidioid-like
4. Bluish-black hypothallus extending beyond lobe edges
5. Soredia as decorticated, small or elongate squamules along the lobe margins; thallus ashen blue, sometimes with yellowish-tan tinge .... Pannaria conoplea
5. Soredia coarsely granular; thallus brownish .... Fuscopannaria ahlneri
4. Bluish-black hypothallus lacking
6. Lobes scabrose or pruinose; soredia marginal .... Physconia detersa s.lat.
6. Lobes not pruinose
7. Thallus light or dark brownish mineral-gray, turning green when wet; soralia capitate .... Phaeophyscia pusilloides
7. Thallus brown, not turning green when wet; soredia are whitish when rubbed off
8. Soredia diffuse over upper surface, mixed with tiny isidia .... Melanelixia (Melanelia) subaurifera
8. Soredia delimited
9. Thallus dull; soralia mainly terminal on short ascending lobe tips .... Melanelia sorediata
9. Outer thallus lobes shiny; soralia laminal and submarginal, appearing as blackened mounds if not abraded .... Melanelia disjuncta
1. Medulla orange-red; soredia coarse, sometimes isidioid .... Phaeophyscia rubropulchra
1. Medulla white
2. Thallus light to dark brownish mineral-gray, turning green when wet
3. Thallus brownish or greenish mineral-gray; lobes usually 0.5-1.5 mm wide .... Phaeophyscia adiastola
3. Thallus blackish mineral-gray; lobes usually <0.5 mm wide .... Phaeophyscia sciastra
2. Thallus brown, not turning green when wet
4. Isidia tiny and mixed with diffuse laminal soredia that are whitish when rubbed off .... Melanelixia (Melanelia) subaurifera
4. Isidia larger and not mixed with soredia
5. Isidia granular to elongated and inflated, spatulate; lower surface tan to dark brown .... Melanohalea (Melanelia) exasperatula
5. "Isidia" really branching lobules; lower surface black .... Melanelia panniformis
1. Lower surface with a blue-black tomentum; red-brown apothecia common .... Pannaria rubiginosa
1. Blue-black tomentum lacking
2. Thallus dark brown
3. Margins of lobes with pycnidial projections and white pseudocyphellae .... Melanelia hepatizon
3. Marginal pycnidial projections and white pseudocyphellae lacking
4. Upper surface of main lobes covered with numerous, fine branching lobules .... Melanelia panniformis
4. Upper surface smooth and shiny with black, immersed pycnidia .... Melanelia stygia
2. Thallus light brown to mineral-gray
5. Lobes without reticulate white markings; rims of apothecia lobulate; lobe tips usually pruinose .... Anaptychia palmulata
5. Lobes with linear white markings
6. White markings laminal and marginal; medulla K+ red .... Parmelia omphalodes
6. White markings marginal only; medulla K- .... Parmelia neodiscordans
(For Peltigera species found on soil on rocks, see Soil Key S2)
1. Sorediate
2. No white spots (pseudocyphellae) on upper surface .... Myelochroa aurulenta
2. Pseudocyphellae on upper surface .... Cetrelia olivetorum s.lat.
1. Nonsorediate
3. Isidiate, often apically ciliate .... Parmotrema crinitum
3. Nonisidiate .... Lobaria quercizans
1. Lobes hollow and inflated; soredia labriform .... Hypogymnia physodes
1. Lobes solid
2. Black lower surface
3. Upper surface of lobe tips weakly reticulately ridged and white spotted; soredia laminal .... Parmelia sulcata
3. Upper surface lacking white markings and spots
4. With linear, suberect lobes bearing cilia on margins; soredia laminal .... Everniastrum catawbiense
4. Lobes appressed; cilia short or lacking
5. Upper surface scabrose or pruinose, at least at lobe tips; soredia marginal .... Physconia detersa s.lat.
5. Upper surface plain, not pruinose
6. Medulla orange-red to red .... Phaeophyscia rubropulchra
6. Medulla white or pale yellow
7. Lobes relatively wide, 2-5 mm; soredia in broad diffuse patches on surface .... Myelochroa aurulenta
7. Lobes narrower, 0.5-1.5 mm
8. Soredia coarse and isidioid .... Phaeophyscia adiastola
8. Soredia powdery, round and delimited (capitate) .... Phaeophyscia pusilloides
2. White or tan lower surface
9. Cilia present on lobe margins (not to be confused with projecting rhizines, see 13a below)
10. Lobes with helmet-shaped inflated tips, sorediate on the inside .... Physcia adscendens
10. Lobes with terminal, labriform soralia; near seashore .... Physcia tenella
9. Cilia lacking
11. Margins of lobes breaking up into granular soredia
12. Lobes narrow (0.1-0.4 mm) and linear, surface even, without mottled white spots; medulla K+ yellow .... Physcia subtilis
12. Lobes broader (0.3-1.0 mm) with mottled white spots on surface; medulla K- .... Physcia millegrana
11. Margins of lobes not breaking up into granular soredia
13. Laterally projecting rhizines at lobe margins; lobes linear and flat with apical or marginal soredia; at least some of lower surface fibrous .... Heterodermia speciosa
13. Laterally projecting rhizines absent; lower surface cortical
14. Upper surface with mottled white spots; soralia capitate, at least in part; medulla K+ yellow .... Physcia caesia
14. Upper surface uniform, soralia mostly marginal and lip-shaped, sometimes laminal and crateriform; medulla K- .... Physcia dubia
1. White markings or spots on upper surface
2. Tips of lobes with white spots (pseudocyphellae) .... Punctelia rudecta
2. Tips of lobes with reticulately ridged, white markings
3. Squarrosely branched rhizines present .... Parmelia squarrosa
3. Rhizines unbranched or branched simple dichotomously, not squarrosely branched .... Parmelia saxatilis
1. Upper surface plain
4. With isidia only, medulla white .... Imshaugia aleurites
4. Soredia coarse granules, sometimes isidioid; medulla red-orange .... Phaeophyscia rubropulchra
1. Margins of lobes and apothecia lobulate .... Anaptychia palmulata
1. Margins of lobes and apothecia not lobulate
2. White to tan lower surface; upper surface with mottled white spots .... Physcia phaea
2. Black to dark brown lower surface (sometimes tan at margin)
3. Lobes hollow, appearing inflated .... Hypogymnia physodes
3. Lobes solid, not appearing inflated, with white linear markings
4. White markings laminal and marginal; medulla K+ red .... Parmelia omphalodes
4. White marking marginal; medulla K- .... Parmelia neodiscordans
(ForPhaeophyscia sciastra, a nongelatinous, dark gray to black, foliose lichen, see Rock Key R6 and R7)
1. White tomentum on lower surface
2. Thallus slate-gray; isidia cylindrical .... Leptogium burnetiae
2. Thallus dark gray to black; isidia granular .... Leptogium saturninum
1. Tomentum lacking
3. Thallus bluish to brownish slate-colored
4. Lobes broad and rotund; bluish slate .... Leptogium cyanescens
4. Lobes narrow, apically dissected and isidiate; brownish (may appear blackish to naked eye) .... Leptogium lichenoides
3. Thallus dark gray to black
5. Thallus distinctly ridged and pustulate; isidia cylindrical in part .... Collema furfuraceum
5. Thallus surface generally even; isidia not cylindrical
6. Isidia squamiform, at least in part; rare .... Collema flaccidum
6. Isidia large and spherical .... Collema fuscovirens
1. Collected submerged on rocks in streams .... Peltigera hydrothyria
1. Not found submerged in streams
2. Thallus greenish black .... Collema nigrescens
2. Thallus bluish to brownish slate-colored
3. Lobes narrow, apically dissected to isidioid .... Leptogium lichenoides
3. Lobes broader, not apically dissected .... Leptogium corticola
1. Thallus yellowish green; apothecia flesh-colored; thalli crowded together, appearing crustose .... Rhizoplaca subdiscrepans
1. Thallus not yellowish green; apothecia not flesh-colored
2. Upper surface with black dots (perithecia) .... Dermatocarpon miniatum s.lat.
2. Upper surface without black dots
3. Upper surface with papillate, cylindrical, or leaf-like isidia .... Umbilicaria deusta
3. Upper surface without isidia
4. Upper surface strongly pustulate
5. Lower surface brown to tan .... Lasallia papulosa
5. Lower surface black .... Lasallia pennsylvanica
4. Upper surface not strongly pustulate
6. Upper surface reticulately ridged towards center; some long rhizines on lower surface .... Umbilicaria proboscidea
6. Upper surface not reticulately ridged
7. Lower surface black, covered with dense mat of short black rhizines; upper surface plain
8. Upper surface brownish .... Umbilicaria mammulata
8. Upper surface whitish gray
9. Found in temperate habitats .... Umbilicaria americana
9. Found in alpine and subalpine habitats .... Umbilicaria vellea
7. Lower surface not covered with dense mat of black rhizines
10. Lower surface with irregular plated and/or flattened rhizines
11. Margins finely perforated and lacerated; deeply grooved on upper surface .... Umbilicaria torrefacta
11. Margins entire; no cracks on upper surface .... Umbilicaria muehlenbergii
10. Lower surface smooth and bare
12. Upper surface rugose with an intricate pattern of ridges .... Umbilicaria hyperborea
12. Upper surface smooth; thallus dissected and irregularly ascending .... Umbilicaria polyphylla
1. Conspicuous blue-black hypothallus surrounding squamules with isidia on margins .... Parmeliella triptophylla
1. Blue-black hypothallus and isidia lacking .... (see Soil Key S4) Cladonia spp.
1. Nonsorediate .... (see Soil Key S5) Cladonia spp.
1. Sorediate
2. Soredia forming broad white patches over the exposed medulla, especially at lobe tips .... Ramalina pollinaria
2. Soredia not forming broad white patches
3. Soredia farinose and restricted to delimited lateral soralia; lobe tips not finely divided .... Ramalina farinacea
3. Soredia granular, irregularly spreading over adjacent area; lobe tips finely divided .... Ramalina intermedia
1. On rocks in or near the water of lakes and streams; appearing as "furry" mats at waterline .... Ephebe lanata
1. Not associated directly with water .... (see Tree Key T20) Bryoria spp.
1. Stalks lacking phyllocladia
2. Stalks simple, topped with a reddish-brown apothecia .... Baeomyces rufus
2. Stalks intricately branched .... Cladonia rangiferina
1. Branches or stalks covered with lobule-like, whitish phyllocladia
3. Soredia in capitate soralia .... Stereocaulon pileatum
3. Nonsorediate
4. Pseudopodetia covered with thick spongy tomentum .... Stereocaulon tomentosum
4. Tomentum, if present, not thick and spongy
5. Phyllocladia cylindrical and branching (coralloid), at least in part
6. Prostrate-decumbent, forming dorso-ventral mats; apothecia and cephalodia rare; gray tomentum often present; phyllocladia incised squamiform to coralloid squamiform .... Stereocaulon saxatile
6. More erect, not prostrate-decumbent
7. Phyllocladia partly grain-like and partly coralloid; apothecia usually common .... Stereocaulon intermedium
7. Phyllocladia not grain-like, usually all coralloid
8. Apothecia common .... Stereocaulon dactylophyllum
8. Apothecia rare .... Stereocaulon subcoralloides
5. None of phyllocladia coralloid
9. Prostrate-decumbent, forming dorso-ventral mats; apothecia and cephalodia rare; gray tomentum often present; phyllocladia incised squamiform .... Stereocaulon saxatile
9. More erect, not prostrate-decumbent
10. Cephalodia conspicuous; dark brown; phyllocladia grain-like, usually on soil .... Stereocaulon paschale
10. Cephalodia usually not conspicuous; phyllocladia not all grain-like
11. Apothecia uncommon; phyllocladia vary from grain-like to lobate squamiform .... Stereocaulon glaucescens
11. Apothecia usually common; phyllocladia digitate squamiform .... Stereocaulon dactylophyllum
1. Lobes very broad, 20-30 mm; lower surface black centrally and tan at margins; rare .... Nephroma arcticum
1. Apothecia round, sunken in pits in the upper surface; rare .... Solorina saccata
1. Apothecia not present, or if present not sunken in pits in the upper surface
2. Upper surface spotted by numerous gray to brown, peltate, often finely crenate cephalodia; algal layer of thallus bright green, consisting of green algae
3. Lower surface with distinct, grayish brown, marginally paler veins .... Peltigera leucophlebia
3. Lower surface lacking distinct veins, dark centrally with paler margins .... Peltigera aphthosa
2. Upper surface without cephalodia; algal layer of thallus dark, composed of cyanobacteria
4. Upper surface distinctly isidiate or margins finely lobulate
5. Isidia scattered on upper surface; lobe margins flat and even, without lobules
6. Isidia fine, basally constricted, granular, flattened, or weakly coralloid .... Peltigera evansiana
6. Isidia peltate .... Peltigera lepidophora
5. No isidia on upper surface; lobe margins or cracks with small lobules or lobule-like isidia
7. Lower surface without veins but with dark tomentum demarcating pale tomentose spots .... Peltigera elisabethae
7. Lower surface with typical dark, raised veins, paler at margins .... Peltigera praetextata
4. Upper surface and margins lacking isidia, although coarse lobules or regeneration squamules may be present
8. Upper surface, at least at lobe tips, distinctly tomentose
9. Thallus small; (lobes usually <4 cm) with small lobes (up to 10 mm broad) that in young specimens are regularly rounded and cupped and bear coarsely granular soredia in round laminal soredia; older specimens are nonsorediate with apothecia borne on ascending, revolute lobes .... Peltigera didactyla s.lat.
9. Thallus larger, with broader lobes that are always nonsorediate
10. Lower surface veinless .... Peltigera malacea
10. Lower surface with distinct veins
11. Lobes <15 mm broad; thallus thick and brittle with margins often strongly undulating, rarely downward curving .... Peltigera rufescens
11. Lobes broad, (13)20-50 mm; thallus thin and pliable with margins mostly down curving
12. Tomentum extending several cm from margins with thallus center often rough or subpruinose, not shiny and smooth; rhizines finely frayed and becoming confluent; lobes (15)20-30 mm broad .... Peltigera canina
12. Tomentum usually present only close to lobe margin; thallus center smooth and often shiny; rhizines slender and unbranched to slightly frayed towards tips, not confluent; lobes on average either larger or smaller than 20-30 mm
13. Lobes (15)25-50 mm broad, thin and papery; rhizines very long (to 15 mm), often tomentose .... Peltigera membranacea
13. Lobes (13)15-25 mm broad, moderate in thickness; rhizines to about 5 mm long .... Peltigera praetextata
8. Upper surface of lobes not tomentose
14. Thallus small (<4 cm) with small lobes (up to 10 mm broad) that in young specimens are regularly rounded and cupped and bear coarsely granular soredia in round laminal soralia; older specimens are nonsorediate with apothecia borne on ascending, revolute, nonsorediate lobes .... Peltigera didactyla s.lat.
14. Thallus larger, with broader lobes that are always nonsorediate
15. Lower surface with well-defined, acutely branching narrow, raised veins .... Peltigera degenii
15. Lower surface with white areas between relatively flat and broad, rounded branching veins, or veins completely lacking
16. Upper surface distinctly roughened and scabrose appearing dull .... Peltigera scabrosa
16. Upper surface smooth, not scabrose, often shiny
17. Lower surface without veins but with dark tomentum demarcating pale tomentose spots; often with lobules on margins of lobes .... Peltigera elisabethae
17. Low veins discernible on lower surface; marginal lobules absent
18. Apothecia marginal, sessile, or on very short very short lobes, disks flat .... Peltigera horizontalis
18. Apothecia absent or raised on narrow lobes; disks saddle-shaped
19. Apothecia grayish brown to black; lobes rather narrow, 5-15 mm .... Peltigera neckeri
19. Apothecia reddish brown; lobes 10-30(40) mm broad
20. Lobes 20-40 mm broad; rhizines long, slender and unbranched .... Peltigera neopolydactyla
20. Lobes 10-20 mm broad; rhizines short (<5 mm)
21. Rhizines in concentric arcs near margins; pale areas between veins generally elongate and neatly radiating .... Peltigera horizontalis
21. Rhizines randomly arranged near thallus margin; pale areas between veins generally rounded or irregular, not distinctly radiating .... Peltigera polydactylon
1. Thallus lobes with swollen and plicate margins .... Collema tenax
1. Thallus with margins apically dissected to isidiate
2. Lobes tiny, to 0.2 mm broad, flattened to nearly round in cross section, appearing as clustered coralloid growths; rare .... Leptogium tenuissimum
2. Lobes 1-4 mm broad, with margins finely lobulate .... Leptogium lichenoides
1. Squamules gray or blackish; apothecia reddish brown .... Protopannaria pezizoides
1. Squamules yellowish, greenish gray, or brown; included below are those species commonly forming large squamulose mats without any podetia; many other Cladonia species will form small patches without podetia and cannot be easily identified
2. Squamules finely divided and incised; apothecia, if present, sessile or on very short podetia (<1.0 mm) .... Cladonia caespiticia
2. Squamules not finely divided
3. Squamules brownish to greenish above, whitish below, often forming compact heads; C+ green .... Cladonia strepsilis
3. Squamules greenish above, whitish below; C-
4. Squamules large and irregular, up to 7 mm × 25 mm, upper surface often rugose; K+ weakly yellow .... Cladonia turgida
4. Squamules more uniformly strap-shaped, branching dichotomously, up to 4 mm wide, upper surface smooth; K+ yellow changing to red .... Cladonia polycarpoides
1. Thallus lobes flattened and strap-shaped; alpine
2. Lobes smooth to faintly rugose, curled into channels .... Flavocetraria cucullata
2. Lobes deeply rugose and more flattened .... Flavocetraria nivalis
1. Thallus branches round in cross-section; widespread
3. Surface of branches dull and fibrous, lacking a cortex
4. Main branches 2-5 mm in diameter, inflated and irregularly perforated .... Cladonia boryi
4. Main branches <2 mm in diameter, not inflated or perforated
5. Thallus forming compact, rounded heads .... Cladonia stellaris
5. Thallus forming extensive entangled colonies
6. Apical branches mostly in pairs
7. Axils of branches all closed; K- .... Cladonia subtenuis
7. Axils of branches both open and closed; K+ .... Cladonia terra-novae
6. Apical branches mostly in 3's and 4's with some 2's
8. Apical branches curved in one direction, mostly in 3's, with 2's not uncommon; widespread .... Cladonia arbuscula s.lat.
8. Apical branches not curved in one direction but showing wide angulation, mostly in 4's with 2's rare; sprawling on sandy soil; southern Maine .... Cladonia submitis
3. Surface of branches shiny and corticate
9. Tips of podetia often flaring into shallow cups .... Cladonia amaurocraea
9. Tips of podetia pointed, not cup-forming .... Cladonia uncialis
1. Branches flattened in cross-section
2. Forming dense tufts with many narrow, finely branched (<1 mm) apical branches .... Cetrariella delisei
2. Apical branches wider (>1 mm) and more coarsely branched
3. White, marginal pseudocyphellae poorly formed .... Cetraria islandica ssp. crispiformis
3. Scattered or continuous, white, linear, marginal pseudocyphellae present and conspicuous
4. Marginal projections blunt-tipped, uniform width, frequently branched; alpine .... Cetraria laevigata
4. Marginal projections tapering to a point; infrequently branched; boreal and temperate .... Cetraria arenaria
1. Branches round in cross-section
5. Thallus uniformly dark brown; numerous apical spiny projections present
6. Lobes c. 0.5 mm wide, nearly round in cross section; pseudocephellae indistinct .... Cetraria muricata
6. Lobes c 1.0 mm wide, flattened at axils; pseudocephellae obvious, in depressions .... Cetraria aculeata
5. Thallus not uniformly dark brown, lacking apical spiny projections
7. Thallus hollow
8. Blunt channeled tips actually multi-branched proliferations of older cups .... Cladonia multiformis
8. No evidence of proliferated cups near center of tufted thallus; tips not channeled .... Cladonia furcata
7. Thallus solid
9. Dichotomously branched, with no distinct main stems; alpine .... Sphaerophorus fragilis
9. Main branches distinct, with numerous side branches; rare .... Sphaerophorus globosus
1. Branches covered with lobule-like phyllocladia (See also Rock Key R19)
2. Primary crustose thallus persistent, of warty or elongated and incised phyllocladia, usually with abundant dark cephalodia interspersed among them; pseudopodetia 1-2 cm tall .... Stereocaulon condensatum
2. Primary thallus lacking; pseudopodetia 2-6 cm tall
3. Tomentum on branches thick and conspicuous; phyllocladia crenate squamiform .... Stereocaulon tomentosum
3. Tomentum less conspicuous or lacking; phyllocladia various
4. Cephalodia abundant, dark brown and scabrose; phyllocladia small and grain-like .... Stereocaulon paschale
4. Cephalodia inconspicuous; phyllocladia verrucose to crenate-squamiform; alpine .... Stereocaulon alpinum
1. Branches of stalks smooth
5. Surface dull and fibrous, without a cortex
6. Basal cartilaginous layer of podetia coal black demarcating scattered overlying whitish patches .... Cladonia stygia
6. Basal cartilaginous layer of podetia gray to brownish .... Cladonia rangiferina
5. Surface corticate, usually shiny
7. Thallus hollow
8. Blunt channeled tips actually multi-branched proliferations of older cups .... Cladonia multiformis
8. No evidence of proliferated cups near center of tufted thallus; tips not channeled .... Cladonia furcata
7. Thallus solid
9. Dichotomously branched, with no distinct main stems; alpine .... Sphaerophorus fragilis
9. Main branches distinct, with numerous side branches; rare .... Sphaerophorus globosus
1. Podetia hollow; primary thallus squamulose
2. Podetia sorediate
3. Forming cups
4. Primary squamules large, 5-15 mm in diameter; K+ or K-
5. Podetia tall (2.5-8.5 cm) and slender, with longitudinal cracks and fissures; squamules only sometimes sorediate; K- .... Cladonia sulphurina
5. Podetia often short and poorly formed, sometimes absent, but can be up to 4 cm tall, lacking longitudinal cracks and furrows; squamules always sorediate on undersides and margins; K+ yellow .... Cladonia digitata
4. Primary squamules smaller, <5 mm; K-
6. Podetia tall (2.5-8.5 cm) and slender, with longitudinal cracks and fissures; squamules nearly 5 mm in diameter .... Cladonia sulphurina
6. Podetia without longitudinal cracks and fissures; or such cracks and fissures rare
7. Cups tall and slender, 2-4(8) cm; soredia farinose; red pycnidia common but apothecia rare; squamules small (2-4 mm) or absent .... Cladonia deformis
7. Cups short, 1-2(4) cm; soredia granular (do not confuse with finely verrucose areolae ofCladonia coccifera); red pycnidia and apothecia common .... Cladonia pleurota
3. Not forming cups
8. Primary squamules large, >5 mm .... Cladonia digitata
8. Primary squamules small, <5 mm
9. Apothecia sessile on the primary squamules or on the tip of small podetia (up to 0.7 cm tall); primary squamules persistent, crenate or incised, usually sorediate; up to 4 mm wide .... Cladonia incrassata
9. Podetia larger; squamules small and poorly developed, up to 4 mm but usually less, generally sorediate
10. Podetia sometimes branched, with large corticate area remaining; soredia granular .... Cladonia floerkeana
10. Podetia usually simple and pointed, largely ecorticate and with farinose soredia .... Cladonia macilenta
2. Podetia without soredia, (although areolae in Cladonia coccifera may be confused with granular soredia); apothecia common
11. Forming cups that are usually finely verrucose areolate in upper part; usually alpine .... Cladonia coccifera
11. Not forming cups; apothecia large and usually red but may be pale yellowish orange; widespread .... Cladonia cristatella
1. Podetia (pseudopodetia) solid; primary thallus crustose
12. Apothecia pink, large, and spherical .... Dibaeis baeomyces
12. Apothecia reddish brown, small, and flattened .... Baeomyces rufus
1. Podetia forming distinct cups
2. Cups deep, stout to elongate, proliferating on edges or not
3. Soredia granular .... Cladonia chlorophaea s.lat.
3. Soredia farinose, cups not proliferating
4. Podetia slender; cups <5 mm wide; sorediate throughout .... Cladonia fimbriata
4. Podetia with wider cups, often 5 or more mm wide; soredia largely restricted to upper third of podetia .... Cladonia innominata (humilis)
2. Cups shallow, usually small, or cups open, funnel-like
5. Cups open, funnel-like with inrolled margins soredia farinose .... Cladonia cenotea
5. Cups not funnel-like, without inrolled margins
6. Soredia granular; cups with dentate or proliferating margins .... Cladonia rei
6. Soredia farinose; cups, where present, tiny and poorly formed
7. Primary squamules conspicuous, 2-5 mm, with podetia arising from centers; podetia <3 cm long, sorediate throughout .... Cladonia coniocraea s.lat.
7. Primary squamules usually disappearing; podetia much longer, 2-12 cm, sorediate only near the tip, often in definite patches .... Cladonia cornuta
1. Podetia not forming cups or only forming them rarely
8. Podetia unbranched, <5 cm tall
9. Primary squamules margins granular sorediate podetia <1 cm tall .... Cladonia parasitica
9. Primary squamules not granular sorediate; podetia >1 cm tall
10. Primary squamules conspicuous, 2-7 mm long
11. Podetia decorticate, with farinose soredia, arising from center of primary squamules .... Cladonia coniocraea s.lat.
11. Podetia sparsely granular sorediate, densely or loosely covered with squamules similar to the primary squamules .... Cladonia acuminata
10. Primary squamules small, <2 mm long
12. Podetia blunt, with farinose soredia merging at base with coarse, isidioid granules and minute squamules .... Cladonia cylindrica
12. Soredia granular throughout podetial extent .... Cladonia ramulosa
8. Podetia long and slender, often branched several times, 3-12 cm tall
13. Open axils; much branched
14. Soredia coarsely granular .... Cladonia scabriuscula
14. Soredia farinose .... Cladonia farinacea
13. Closed axils; little branched
15. Mostly corticate; farinose soredia only near the tip, often in definite rounded patches .... Cladonia cornuta
15. Mostly decorticate and covered with farinose soredia .... Cladonia subulata
1. Primary thallus crustose and persistent
2. Podetia (pseudopodetia) solid .... Baeomyces rufus
2. Podetia hollow and inflated .... Pycnothelia papillaria
1. Primary thallus squamulose, sometimes disappearing at maturity
3. Forming cups
4. Cups proliferating from the center
5. Cups gradually expanding from stalks, bowl-like; podetia usually 1-2 mm at narrowest .... Cladonia verticillata
5. Cups shallow, like flat saucers; podetia delicate, usually <1 mm wide at narrowest .... Cladonia rappii
4. Cups proliferating from the margins or not at all
6. Cups coarse and stout, covered with greenish areoles and peltate squamules .... Cladonia pyxidata
6. Cups gradually tapering, areoles not conspicuous
7. Centers of cups closed
8. Cups large, >5 mm wide, with margins dentate or proliferating; apothecia common .... Cladonia gracilis ssp. turbinata
8. Cups smaller, usually <5 mm wide, sometimes absent; podetia slender and tall
9. Podetia robust, 1.5-3 mm thick, 6-10 cm tall .... Cladonia maxima
9. Podetia thin, 1-1.5 mm thick, 3-6 cm tall .... Cladonia gracilis ssp. gracilis
7. Centers of cups open or perforated
10. Cups perforated
11. Podetia yellowish green, richly branched .... Cladonia amaurocraea
11. Podetia greenish white to brown, variously branched; cup membrane perforated with holes .... Cladonia multiformis
10. Cups open and gaping
12. Podetia finely and densely squamulose .... Cladonia squamosa
12. Podetia with squamules either coarse or sparse
13. Basal squamules large, 5-25 mm long; podetia lacerate and perforate .... Cladonia turgida
13. Basal squamules small, 1-4 mm, or lacking
14. Podetia relatively short, <5 cm, usually with numerous coarse squamules .... Cladonia atlantica
14. Podetia usually taller, to 10 cm, with few squamules .... Cladonia crispata
3. Not forming cups
15. Podetia barely developed, very short, or lacking including those species commonly forming large squamulose mats with few if any podetia; many other Cladonia species will form small patches without podetia and cannot be easily identified; see Soil Key S4, couplets 2-4
15. Podetia simple to branched, usually well developed
16. Podetia richly branched; axils open
17. Yellowish green .... (see Soil Key S5)
17. Greenish white to brown
18. Blunt channeled tips actually multi-branched proliferations of older cups .... Cladonia multiformis
18. No evidence of proliferated cups near center of thallus; tips not channeled .... Cladonia furcata
16. Podetia simple or moderately branched; axils open or closed
19. Podetia finely and densely squamulose .... Cladonia squamosa
19. Podetia with squamules either coarse or sparse
20. Primary squamules conspicuous and large, 4-25 mm long
21. Podetia lacerate and perforate; squamules very large, often free of substrate .... Cladonia turgida
21. Podetia entire; squamules 5-15 mm long and strap-shaped; attached to soil
22. Squamules 5-15 mm long; K+ yellow changing to red .... Cladonia polycarpoides
22. Squamules mostly near 5 mm long; K- .... Cladonia sobolescens
20. Primary squamules smaller, 1-4 mm long, or absent
23. Podetia bone-white, pointed, and wormlike; no squamules; alpine .... Thamnolia subuliformis
23. Podetia not bone-white, pointed and wormlike
24. Podetia tall, 3-10 cm
25. Podetia moderately branched, often tipped with apothecia .... Cladonia crispata
25. Podetia unbranched or sparsely branched, ending in a point, cup, or larger apothecia
26. Podetia robust, 1.5-3 mm thick, 6-10 cm tall .... Cladonia maxima
26. Podetia thin, 1-1.5 mm thick, 3-6 cm tall .... Cladonia gracilis ssp. gracilis
24. Podetia shorter, usually <3 cm
27. Apothecia tan or flesh-colored; rare .... Cladonia botrytes
27. Apothecia brown to black
28. Apothecia small, <width of podetia, usually covered with coarse squamules .... Cladonia atlantica
28. Apothecia larger, as wide as or wider than podetia; podetial squamules small or lacking
29. Podetia usually unbranched; apothecia smaller than or only slightly exceeding width of podetia .... Cladonia brevis
29. Podetia branched apically; sides markedly fissured and torn; apical apothecia clearly wider than subtending podetia .... Cladonia cariosa
1. Soredia present
2. Lobes narrow, (0.3)0.4-0.5 mm wide; apical soralia ....Xanthomendoza weberi
2. Lobes wider, (0.8)1.1-1.4 mm wide; marginal soralia
3. Soredia linear on lobe margins ....Xanthomendoza ulophyllodes
3. Soredia in pockets of up-turned margins ....Xanthomendoza fallax
1. Without soredia or isidia; apothecia usually common
4. Lower surface with noticeable rhizines; thallus cushion-like ....Xanthomendoza hasseana
4. Lower surface with sparse or abundant holdfasts; without rhizines
5. Lobes +/- adherent to the substrate, >0.5 mm wide .... Xanthoria parietina
5. Lobes and apothecia crowded together forming small cushion; lobes <0.5 mm .... Xanthoria polycarpa
1. Thallus yellow, lobes tiny (0.1-0.5 mm wide)
2. Sorediate; apothecia rare .... Candelaria concolor
2. Nonsorediate; apothecia common .... Candelaria fibrosa
1. Thallus yellow-green; lobes >0.5 mm wide
3. Nonsorediate; apothecia and marginal pycnidia common .... Ahtiana aurescens
3. Sorediate
4. Lobes 3-10 mm; soredia forming confluent pustulate masses .... Flavoparmelia caperata
4. Lobes narrower, 0.5-3.0 mm wide
5. Medulla and soredia lemon yellow .... Vulpicida pinastri
5. Medulla and soredia white
6. Soralia on margins, linear .... Usnocetraria (Allocetraria) oakesiana
6. Soralia on surface or tips, spherical .... Parmeliopsis capitata
1. Sorediate
2. Soredia bright yellow ....Pseudocyphellaria crocata s.lat.
2. Soredia gray to brown
3. Lower surface bare; found on tree bases over moss .... Nephroma parile
3. Lower surface tan-tomentose with gaps showing white
4. Lobe tips dichotomously branched; upper surface strongly reticulate-ridged .... Lobaria pulmonaria
4. Lobe tips rounded; upper surface weakly ridged to undulating; often yellowish .... Lobaria scrobiculata
1. Nonsorediate
5. Margins of lobes lobulate to dentate-isidiate; at the base of trees .... Nephroma helveticum
5. Neither sorediate nor isidiate
6. Lower surface tan tomentose
7. White papillae scattered among tomentum; apothecia on lower surface .... Nephroma resupinatum
7. White papillae on lower surface lacking; apothecia on upper surface .... Lobaria quercizans
6. Tomentum not present
8. Thallus adnate; margins and lower surface of lobes smooth at base of trees .... Nephroma bellum
8. Thallus suberect; margins of lobes with pycnidial projections or cilia; rhizines on lower surface; on branches .... Tuckermannopsis ciliaris s.lat
1. Bluish-black hypothallus extending beyond edges of lobes
2. Soredia in form of partly decorticated, small or elongate lobules along the lobe margins; thallus bluish .... Pannaria conoplea
2. Soredia coarsely granular; thallus brownish .... Fuscopannaria ahlneri
1. Bluish-black hypothallus lacking
3. Soredia diffuse over upper surface, mixed with tiny isidia, white showing where abraded .... Melanelixia (Melanelia) subaurifera
3. Soredia in delimited round or linear soralia
4. Upper surface of at least the lobe tips white pruinose (may need lens)
5. Soralia linear and marginal, KC- .... Physconia detersa s.lat.
5. Soralia discrete labriform, KC+ orange .... Physconia leucoleiptes
4. Upper surface lacking pruina
6. Tan or white lower surface; soredia marginal and labriform on lobe tips .... Physciella chloantha
6. Black lower surface
7. Medulla orange-red .... Phaeophyscia rubropulchra
7. Medulla white
8. Soredia coarse, isidioid .... Phaeophyscia adiastola
8. Soredia powdery, round and delimited (capitate) .... Phaeophyscia pusilloides
1. Conspicuous blue-black hypothallus surrounding thallus of small squamulose lobes .... Parmeliella triptophylla
1. No hypothallus visible
2. Isidia tiny and mixed with diffuse laminal soredia, white when rubbed off .... Melanelixia (Melanelia) subaurifera
2. Isidia larger, often branched, not mixed with soredia
3. Isidia flattened and lobulate .... Melanohalea (Melanelia) exasperatula
3. Isidia thin and cylindrical
4. Thallus uniformly brown .... Melanelixia (Melanelia) fuliginosa
4. Thallus mineral-gray, brown only on lobe tips, which are reticulately ridged with markings .... Parmelia saxatilis
1. Lower surface with bluish-black tomentum .... Pannaria rubiginosa
1. Lower surface without bluish-black tomentum
2. Pycnidial projections on lobe margins and apothecia; thallus suberect
3. Thallus 2-6 cm wide, lobes usually >0.6 mm wide .... Tuckermannopsis ciliaris s.lat.
3. Thallus cushion-like, 1-2 cm wide; lobes <0.6 mm
4. Lobes finely divided at tips .... Tuckermanella fendleri
4. Lobes entire .... Tuckermannopsis sepincola
2. No pycnidial projections; thallus clearly foliose
5. Thallus brown, not changing in color when wet
6. Apothecia mostly flat, with thin margins, present to the edges of the lobes; thallus smooth .... Melanohalea (Melanelia) septentrionalis
6. Apothecia cup-like with thick and crenate margins, not present to the edge of lobes; thallus rugose .... Melanohalea (Melanelia) halei
5. Thallus grayish brown, turning green when wet
7. Lobe margins and apothecial margins entire, without lobules; lower surface black .... Phaeophyscia ciliata
7. Lobe margins and rims of apothecia lobulate; lower surface tan .... Anaptychia palmulata
(for Peltigera species which may be found at the base of the trees or on fallen logs, see Soil Key S2)
1. White spots (pseudocyphellae) visible on upper surface (may need lens)
2. Tan lower surface .... Punctelia caseana (perreticulata, subrudecta)
2. Black or dark brown lower surface .... Cetrelia olivetorum s.lat.
1. No white spots on the upper surface
3. Lower surface tan-tomentose with gaps showing white
4. Lobe tips dichotomously branched; upper surface strongly reticulately ridged .... Lobaria pulmonaria
4. Lobe tips rounded; upper surface weakly ridged to undulating; often yellowish .... Lobaria scrobiculata
3. Lower surface bare or with rhizines, not tomentose
5. Long cilia present on lobe margins; soredia on revolute lobe tips .... Parmotrema perlatum
5. Long cilia lacking
6. Lobes broad and ascending; soredia becoming granular or subisidioid in dissected lobe margins .... Platismatia glauca
6. Lobes narrower and appressed; soredia laminal and diffuse .... Myelochroa aurulenta
(for Peltigera species which may be found at the base of the trees or on fallen logs, see Soil Key S2)
1. Isidia dense, laminal, often branched, and apically ciliate .... Parmotrema crinitum
1. Isidia/soredia on lobe margins; without cilia .... Platismatia glauca
(for Peltigera species which may be found at the base of the trees or on fallen logs, see Soil Key S2)
1. Thallus subfruticose, with sharp reticulate ridges on upper surface of lobes .... Platismatia tuckermanii
1. Thallus flattened, with smooth upper surface .... Lobaria quercizans
1. Sorediate; apothecia rare
2. Upper surface more or less uniformly perforated with holes; soredia capitate on short cylindrical stalks .... Menegazzia terebrata s.lat.
2. Upper surface entire
3. Soralia labriform on relatively broad lobe tips .... Hypogymnia physodess.lat
3. Soralia ring-shaped on ends of narrow suberect lobes .... Hypogymnia tubulosa
1. Nonsorediate
4. Lower surface with thick, spongy layer of tomentum; lobes solid but sometimes appearing inflated; rare .... Anzia colpodes
4. Lower surface without spongy tomentum; lobes hollow
5. Lobes narrow; apothecia and pycnidia common .... Hypogymnia krogiae
5. Lobes generally broader and somewhat fan-shaped; usually sorediate; apothecia rare .... Hypogymnia physodes
(if bluish-black hypothallus present, see Tree Key T4 Pannaria, Fuscopannaria)
1. Black or dark brown lower surface
2. Medulla pale yellow, yellow, orange or red
3. Lobes 2-6 mm wide, loosely adnate .... Myelochroa aurulenta
3. Lobes 1-2 mm wide, closely adnate
4. Medulla orange-red to red .... Phaeophyscia rubropulchra
4. Medulla pale yellow to salmon orange; lobe margins white and ecorticate; lobe tips usually pruinose .... Pyxine sorediata
2. Medulla white
5. Ciliate
6. Lobes suberect; cilia obvious; uncommon and local .... Everniastrum catawbiense
6. Lobes adnate; cilia very short, often not seen .... Myelochroa aurulenta
5. Cilia lacking
7. Upper surface of lobes with reticulate white markings .... Parmelia sulcata
7. Upper surface without reticulate white markings
8. Soralia marginal; upper surface of lobe tips pruinose
9. Soralia linear and marginal; K- .... Physconia detersa s.lat.
9. Soralia discrete labriform; KC+ orange .... Physconia leucoleiptes
8. Soralia laminal or terminal
10. Lobes2-5 mm wide soralia in broad diffuse patches on surface .... Myelochroa aurulenta
10. Lobes 0.3-1.5 mm wide
11. Soredia coarse and isidioid, in marginal and terminal soralia .... Phaeophyscia adiastola
11. Soredia powdery and in capitate soralia .... Phaeophyscia pusilloides
1. White or tan lower surface
12. Margins of lobes dissected, breaking up into granular soredia .... Physcia millegrana
12. Lobes without dissected margins
13. Cilia or laterally projecting rhizines on lobe margins
14. Lobes linear and flat with marginal soredia; at least some of the lower surface white cottony .... Heterodermia speciosa
14. Lobes suberect with apical soralia
15. Lobes with helmet-shaped inflated tips, sorediate on the inside .... Physcia adscendens
15. Lobes with terminal labriform soralia .... Physcia tenella
13. Cilia or projecting rhizines lacking on lobe margins
16. Upper surface with white pores (pseudocyphellae) or mottled with white spots
17. With pseudocyphellae; found only on trees .... Punctelia caseana (perreticulata, subrudecta)
17. With mottled white spots; usually on rocks .... Physcia caesia
16. Upper surface without pseudocyphellae or mottled white spots
18. Thallus greenish or brownish gray; soralia marginal labriform and greenish .... Physciella chloantha
18. Thallus mineral-gray; soredia white-powdery in round soralia .... Parmeliopsis hyperopta
1. Thallus loosely attached and subfruticose; lobes suberect .... Pseudevernia consocians
1. Thallus clearly foliose; lobes adnate
2. White spots (pseudocyphellae) on upper surface .... Punctelia rudecta
2. Without white spots
3. Isidia flattened and squamiform; lower surface white and fibrous, lacking a cortex .... Heterodermia squamulosa
3. Isidia not squamiform; lower surface cortical
4. White or tan lower surface .... Imshaugia aleurites
4. Black or dark brown lower surface
5. Surface of lobe tips with reticulate pattern of white lines (pseudocyphellae)
6. Squarrosely branched rhizines present .... Parmelia squarrosa
6. Rhizines unbranched or branched simple dichotomously; not squarrose .... Parmelia saxatilis
5. White reticulate markings absent; medulla orange-red .... Phaeophyscia rubropulchra
1. Thallus subfruticose to fruticose; lobes adnate to erect .... Pseudevernia cladonia
1. Thallus clearly foliose; lobes adnate
2. Lower surface with thick, black, spongy tomentum; rare .... Anzia colpodes
2. Lower surface without thick black tomentum
3. Margins and sometimes upper surface of lobes with numerous squamuate lobules; lower surface white and fibrous, lacking a cortex; apothecia rare .... Heterodermia squamulosa
3. Squamulate lobules absent or, if present, lower surface cortical; apothecia common
4. Lower surface black or dark brown
5. Thallus grayish brown; rhizines often radially projecting around apothecia; upper surface smooth .... Phaeophyscia ciliata
5. Thallus mineral-gray, rhizines not radially projecting; upper surface often wrinkled .... Myelochroa galbina
4. Lower surface white to tan
6. Lobes or rims of apothecia lobulate, lobe tips often pruinose .... Anaptychia palmulata
6. Margins of lobes entire; upper surface not pruinose
7. Upper surface with mottled white spots; medulla K+ yellow .... Physcia aipolia
7. Upper surface without white spots; medulla K+ or K-
8. Apothecia uncommon; marginal soralia usually present .... Heterodermia speciosa
8. Apothecia common
9. Apothecia blackish to white pruinose; medulla K- .... Physcia stellaris
9. Apothecia pale or orange brown .... Imshaugia placorodia
1. White tomentum on lower surface
2. Tomentum very short, hard to see with hand lens; lobes apically dissected to isidiate .... Leptogium laceroides
2. Tomentum long, hairs up to 1 mm or longer, obvious with a hand lens
3. Thallus slate-gray; isidia cylindrical .... Leptogium burnetiae
3. Thallus black; isidia granular .... Leptogium saturninum
1. Without tomentum on lower surface
4. Lobe surface with numerous, narrow, longitudinal wrinkles visible with a hand lens; isidia granular, sparse to abundant .... Leptogium milligranum
4. Lobe surface smooth, pustulate or ridged, without fine longitudinal wrinkles; isidia usually abundant
5. Thallus bluish slate-colored; lobe surface smooth; isidia cylindrical to clavate to lobulate .... Leptogium cyanescens
5. Thallus dull greenish or brownish black
6. Some of isidia in mature part of thallus squamiform; rare .... Collema flaccidum
6. Isidia cylindrical to nearly spherical
7. Thallus surface markedly pustulate and ridged; isidia mostly cylindrical .... Collema furfuraceum
7. Thallus surface not markedly pustulate; isidia mostly nearly spherical .... Collema subflaccidum
1. Bluish slate-colored; surface of lobes finely and irregularly wrinkled .... Leptogium corticola
1. Brown, brownish-black, or greenish black; lobes without fine wrinkles
2. Lobes much divided, up to 0.2 mm broad, flattened to almost round, often short and crowded and appearing as clustered coralloid outgrowths .... Leptogium tenuissimum
2. Lobes larger
3. Thallus 2-6 cm broad with lobes expanded and separate .... Collema nigrescens
3. Thallus 2-3 cm with lobes small, crowded and fused, forming a cushion with interstices; covered with small apothecia .... Collema leptaleum
(ForCladoniaspecies formed at base of trees or on rotting logs without podetia so only squamules are present, see Soil Key S5)
1. Conspicuous blue-black hypothallus surrounding squamules with isidia on margins .... Parmeliella triptophylla
1. Without blue-black hypothallus
2. Lobes much divided, crowded, and appearing as clustered, coralloid outgrowths .... Leptogium tenuissimum
2. Squamules not divided, imbricate, around 1.0 mm long, and sorediate on margins of lower surface .... Hypocenomyce scalaris
1. Branches loosely filled with medullary hyphae, a central dense cord lacking
2. Apices of branches thin and tipped with soredia or granules, often hooked (use lens); black pycnidia not present .... Ramalina thrausta
2. Apices of branches not hooked or tipped with soredia; black pycnidia usually present; pseudocyphellae common, white and raised, ovoid to elongate .... Alectoria sarmentosa
1. Branches with distinct, dense central cord (genus Usnea; if collecting in downeast Maine, see Hinds and Hinds (2007) for additional species)
3. Sorediate
4. Branches, including main branches, with coarse, white tubercles, becoming sorediate .... Usnea ceratina
4. Branches with abundant, isidia-like fibrils; soralia sometimes isidioid .... Usnea filipendula
3. Non-sorediate
5. Cortex eroding away on the main branches, numerous long lateral fibrils present .... Usnea longissima
5. Cortex present and continuous; lateral fibrils less numerous or absent
6. Surface of main branchlets smooth except for annular rings .... Usnea trichodea
6. Surface of main branchlets not smooth
7. Branches coarse, with coarse tubercles .... Usnea ceratina
7. Branches fine, rugose and pitted and without papillae .... Usnea cavernosa
1. Soredia and isidia lacking; apothecia common, with fibrils radiating from disk edge .... Usnea strigosa
1. Sorediate, isidiate, or isidiate-sorediate
2. Sorediate only
3. Branches with papillae tubercles sorediate .... Usnea ceratina
3. Smaller branches with numerous flat or concave soralia containing granular soredia .... Usnea fulvoreagens
2. Isidiate or isidiate-sorediate
4. Surface of branches with orange or reddish color; rare .... Usnea rubicunda
4. Surface of branches yellow-green or greenish-yellow
5. Isidiate only; branches covered with isidia; papillae absent .... Usnea hirta
5. Soredia raised
6. Raised isidiate-sorediate patches present .... Usnea subfloridana
6. Isidiate-sorediate patches absent; branches mostly with isidia or sorediate isidia; usually pendent .... Usnea filipendula
1. Sorediate
2. Soredia diffuse, granular to subisidioid; surface of branches irregularly wrinkled .... Evernia mesomorpha
2. Soredia in distinct marginal or apical soralia
3. Branches hollow and sometimes perforated; tips attenuated with isidioid soredia at tips .... Ramalina roesleri
3. Branches not hollow
4. Soredia forming broad white patches over the exposed medulla .... Ramalina pollinaria
4. Soredia not forming broad white patches
5. Soredia farinose and restricted to delimited lateral soralia; lobe tips not finely divided .... Ramalina farinacea
5. Soredia granular, irregularly spreading over adjacent areas; lobe tips finely divided .... Ramalina intermedia
1. Nonsorediate; apothecia common
6. Branches somewhat rounded, to 1.5 mm wide, hollow and perforated .... Ramalina dilacerata
6. Branches strap-shaped, 2-10 mm wide, solid, surface smooth to striate .... Ramalina americana
1. Soralia present; tufted to subpendent
2. Soralia with projecting tufts of isidioid spinules .... Bryoria furcellata
2. Soralia without projecting isidioid spinules
3. Thallus grayish green to pale brown with basal branches darker; K+ .... Bryoria nadvornikiana
3. Thallus brown; K- .... Bryoria fuscescens
1. Soralia absent; subpendent to pendent
4. Thallus greenish gray to gray; K+ .... Bryoria capillaris
4. Thallus pale to dark brown; K- .... Bryoria trichodes s.lat.
1. Isidiate .... Pseudevernia consocians
1. Isidia (and soredia) lacking .... Pseudevernia cladonia
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last updated 2025-Mar-24
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