[BGBM-Logo] Lichen determination keys
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Key to crustose, not foliicolous lichens

primary / fruticose / foliose / squamulose / foliicolous / crustose / lichinaceae
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1a Ascocarps present---2
1b Ascocarps absent---3

2a Apothecia present---4
2b Perithecia present---200
2c Lirellae present---251

3a Conidangia present (only a selection of common and characteristic species treated)---330
3b Conidangia absent; usually sterile crustose lichens (only a selection of common and characteristic species treated)---351

4a Apothecia covered by powdery, staining masses of ascospores ripening in a layer above the asci (mazaedium); apothecia sessile or sometimes on long, thin stalks and pin-shaped (Caliciales)---5
4b Apothecia not covered by ascospore masses, not staining, releasing ascospores from each ascus separately, immersed or sessile, rarely stalked---19

5a Apothecia pin-shaped, with up to 2 mm long, thin stalk---6
5b Apothecia sessile---8

6a Ascospores simple, pale brown or colourless---7
6b Ascospores one-septate, dark-grey to -brown---Calicium

7a Apothecia dark brownish, but often covered by coloured pruina; ascospores pale brown---Chaenotheca
7b Apothecia reddish brown; ascospores simple, hyaline---Sclerophora
(similar are the not properly lichenized Chaenothecopsis, Mycocalicium andSphinctrina, key in Tibell 1996, Flora Neotr. 69)

8a Apothecia without thalline margin---9
8b Apothecia with thalline margin---10
(see also the rarely reported genera Allophoron, Cyphelium, Mazaediothecium and Tylophorella, key in Tibell 1996, Flora Neotr. 69)

9a Apothecia with distinct proper margin, clearly delimited; ascospores ripening and colouring in the asci---Pyrgidium
9b Apothecia with distinct proper margin, clearly delimited; ascospores ripening and colouring in the mazaedium, outside the asci---Pyrgillus
9c Apothecia without proper margin, indistinctly delimited; ascospores ripening and colouring inside the asci---Sporostigma

10a Ascospores one-septate---11
10b Ascospores two-septate---Heterocyphelium
10c Ascospores three-septate---Schistophoron

11a Ascospores 7-9 x 5-6 Ám; excipulum wide, with corona-like extension---Nadvornikia
11b Ascospores 9-13 4.5-6.5 Ám; excipulum without corona-like extension---Tylophoron

19a (4) Thallus gelatinous, with blue-green algae---lichinaceae, incompletely treated (this concerns probably a.o. Collemopsidium, Finkia, Gyrocollema, Leprocollema, Psorotichia and Pyrenopsis)
19b Thallus not gelatinous---20

20a Hymenium I+ blue, throughout or around the asci, sometimes I+ brownish, and blue after pretreatment with diluted KOH solution; asci I+ blue, at least along their outside, and usually also in their tips; ascospores I-negative, often simple, or variously septate, with rather equal cells; paraphyses usually straight and unbranched, except near the tips, rarely branched and anastomosing (Lecanorales s.l.)---21
20b Hymenium I+ red or blue or mixed red and blue; asci I-negative, except sometimes for a small, I+ blue ring around the ocular chamber; ascospores I-negative, variously septate but not simple, often with a single, much larger cell terminally or (sub)medially; paraphyses usually densely branched and anastomosing (Opegraphales, Arthoniales, Ostropales)---120
20c Hymenium I-negative, rarely diffusely I+ (pale) blue; asci I-negative or rarely pale blue throughout; ascospores I+ blue-violet or I-negative, variously septate but not simple, with rather equal cells (septum formation often centrifugal, so that terminal ascospore parts may lack septation in young ascospores); paraphyses straight and unbranched, except sometimes near the tips, rarely branched and anastomosing (Gyalectales, Graphidales)---160

21a Ascospores grey to brown, at least when old, usually one-septate---22
21b Ascospores persistently hyaline, variously septate---30

22a Epiphytic or on moss or plant debris---23
22b On rock---25

23a Ascospore wall and septa thin---Buellia
23b Ascospore wall and septa thickened---24

24a Apothecia lecideine; ascospore wall thickening mainly along lateral outer walls---Hafellia
24b Apothecia lecanorine or biatorine; ascospore wall thickening usually concentrated near apex and septa---Rinodina

25a Apothecia with thalline margin, lecanorine---26
25b Apothecia without thalline margin, lecideine---27

26a Thallus margin lobate---Dimelaena
26b Thallus margin not lobed---Rinodina

27a Spores with halo, usually muriform---Rhizocarpon
27b Spores without halo, transversely one-, rarely three-septate---28

28a Ascospore septa thin, lumina edged---Buellia
28b Ascospore septa thickened, lumina rounded or more complicated---29

29a Ascospores with thin-walled, rather pointed poles; apothecia lecideine---Hafellia
29b Ascospores with thickened polar walls, not pointed; apothecia biatorine---Rinodina

30a (21) Ascospores simple---31
30b Ascospores transversely septate only---70
30c Ascospores muriform---100

31a Apothecia lecanorine, margin of same colour as thallus, with algal layer---32
31b Apothecia lecideine or biatorine, margin of same colour as disc, without algal layer, or apothecia without distinct margin---45

32a Ascospores under 20 Ám long---33
32b Ascospores over 30 Ám long---42

33a Ascospores many in each ascus---34
33b Ascospores 8 in each ascus---37

34a Thallus coarse-areolated, yellow or brown; on rock; apothecia immersed---Acarospora
34b Thallus continuous or granular- to warty-areolated, grey or yellow, usually epiphytic, sometimes on other substrates; apothecia sessile---35

35a Thallus yellow; epiphytic, on rock or on other substrates---Candelariella
35b Thallus greenish- or brownish grey, epiphytic---36

36a Asci of Lecanora-type, with distinct I+ pale axial mass in tholus---Maronina
36b Asci of Fuscidea-type, with continuously I+ blue tholus---Maronea

37a Ascocarps immersed in the thallus; ascus apex I-negative---Aspicilia
37b Ascocarps sessile, rarely immersed; ascus apex I+ blue---38

38a Hypothecium pale brown to brown---39
38b Hypothecium colourless---40

39a Hymenium colourless---Vainionora
39b Hymenium pale purplish---Tephromela

40a Thallus bright yellow---Candelariella
40b Thallus white, grey or pale yellow---41

41a Conidia pleurogenous; cupular, thickwalled layer in excipulum---Protoparmelia
41b Conidia acrogenous; cupular layer in excipulum absent---Lecanora

42a (32) Ascus apex I+ pale blue; spores (4-)8/ascus---43
42b Ascus apex I+ strongly blue; spores 1-8/ascus; ascocarps immersed in thallus warts or lecanorine---43

43a Ascocarps immersed in thallus warts; ascospores 4/ascus; epiphytic or on moss; cephalodia absent---Megaspora
43b Ascocarps lecanorine; ascospores 8/ascus; on humid rock or road banks; flat, rounded cephalodia present---Placopsis

44a Ascocarps immersed in thallus warts; ascospores thick-walled (c. 5 Ám thick), usually over 60 Ám long---Pertusaria
44b Ascocarps lecanorine; ascospores thin-walled (to c. 2 mm thick), under 50 Ám long---Ochrolechia

44a Normally epiphytic; cephalodia absent---

45a (31) Apothecial disc orange to bright red, K+ purplish to dark violet---46
45b Apothecial disc not orange to bright red, usually brown or black, K----47

46a Apothecial disc bright red, K+ purplish; margin concolorous---Pyrrhospora
46b Apothecial disc orange, K+ dark violet; margin black---Bahianora

47a Ascospores more than 16 per ascus, small and globose---Piccolia
47b Ascospores less than 16 per ascus, not globose---48

48a Paraphyses anastomosing; exciple absent or indistinct; apothecia soon convex and globular---49
48b Paraphyses not anastomosing; exciple present, usually obvious in young apothecia at least; apothecia often flat---51

49a Hymenial gelatine absent---Vezdaea
49b Hymenial gelatine present---50

50a Thallus yellow-green, completely sorediate; apothecia concolorous---Psilolechia
50b Thallus grey to brown, not completely sorediate; apothecia variously coloured---Micarea

51a Asci without tholus, I-negative; on rock at high elevations---Schaereria
51b Asci with distinct, more or less I+ blue tholus---52

52a Asci with weakly I+ blue tholus, in which an I+ blue central tube or small apical I+ blue zone may be present---53
52b Asci with strongly I+ blue tholus, in which a paler axial mass may be present---58

53a Epiphytic or on soil or organic detritus---54
53b Saxicolous; ascus apex various---57

54a Epiphytic; central amyloid tube in ascus apex sometimes present---Malcolmiella
54b On soil or organic detritus; no distinct amyloid structure in ascus apex---55

55a Thallus shades of grey; apothecia pink to dark brown---56
55b Thallus dark brown, in shade more greenish; apothecia black---Placynthiella

58a Apothecia pink to brown, usually less than 1 mm wide, with thin proper margin---Trapelia
58b Apothecia dark brown, 1-3.5 mm wide, with thick, prominent proper margin---Ainoa

57a Central tube in ascus apex more or less clearly present---Porpidia
57b Small apical cap in ascus apex present---Lecidea

58a Asci with I+ pale axial mass in tholus---59
58b Asci with homogeneously I+ blue-staining tholus---60

59a Axial mass with rounded top (Lecanora-type asci); apothecia dark brown to black; thallus whitish or greenish, often K+ yellow or C+ orange; mostly on tree bark or rock (incl. Carbonea, separation under study)---Lecidella
59b Axial mass conical (Bacidia-type); apothecia variously coloured; thallus reactions different; mostly on tree bark---Biatora s.l.

60a Asci with I+ weakly blue-staining tholus; apothecia pink or brownish to blackish discoloured; thallus grey, granular, K-, C+ red; on burnt or decaying worked wood---Trapeliopsis
60b Asci with I+ strongly blue-staining inner and outer apical layer; apothecia dark brown to black; thallus brownish grey; high altitude taxa on rock or tree bark---Fuscidea

70a (30) Apothecia with distinct margin of same colour as thallus, with algae, or immersed in thallus---71
70b Apothecia with margin of different colour as thallus, usually of same colour as disc, or without distinct margin---77

71a Apothecia immersed, with more or less lacerate, erect margin; disc grey to pale brown, often white-pruinose---72
71b Apothecia sessile with constricted base, with entire or crenulate margin---73

72a Paraphyses thick and conspicuously septate and with tiny transverse connections---Phlyctidia
72b Paraphyses slender, simple---Phlyctella

73a Ascospores with thin septa---74
73b Ascospores with distinctly swollen septa---75

74a Spores one-septate; disc yellow to brown, K----"Lecania"
74b Spores transversely many-septate, over five times as long as wide; disc red, K+ purplish---Haematomma

75b Spores one-septate, usually over 15 Ám wide; septa much thinner than spore lumina; disc grey, K- ---Megaloblastenia
75a Spores variously septate; septa usually about as thick as lumina; disc yellow to red or brownish, mostly K+ purplish---76

76a Ascospores one- to three-septate---Caloplaca
76b Ascospores more than three-septate---Letrouitia

77a Ascospores one-septate---78
77b Ascospores two- or more-septate---84

78a Ascospores 2-4(rarely to 8) per ascus, over 30 Ám long; hymenium guttulate or clear---79
78b Ascospores 8 per ascus, under 30 Ám long; hymenium clear---80

79a Ascospores 2 in each ascus, over 40 Ám long; hymenium clear---Lopezaria
79b Ascospores 2-8 in each ascus, over 30 Ám long; hymenium inspersed with oil-like droplets---Megalospora

80a Ascospores with thick septa (polarilocular); disc mostly K+ dark violet---Caloplaca
80b Ascospores with thin septa; disc K---81

81a Apothecia without distinct margin, very soon globose---Micarea
81b Apothecia with a distinct margin, at least when young---82

82a Asci with ocular chamber surrounded by I+ weakly staining, rounded axial mass (Lecanora-type); ascospores not halonate; exciple with well-defined cortical and medullary parts, but lacking algae---Megalaria
82b Asci without rounded, I+ weakly staining axial mass around ocular chamber; ascospores halonate or not; exciple compact---83

83a Ascus tholus containing a conical, I+ weakly staining axial mass around ocular chamber; ascospores halonate---Catinaria
83b Ascus tholus containing a tubular, I+ strongly staining structure; apothecia yellowish; ascospores not halonate---"Catillaria" s.l.

84a (77) Ascospores extremely large, broadly ellipsoid, 70-140 x 25-35 Ám, single---Megalospora
84b Ascospores under 10 Ám wide, long fusiform to filiform, usually 8 in each ascus---85

85a Ascospores with thick septa, up to 3-septate; disc mostly K+ dark violet (when ascospores with more than 3 septa, see Letrouitia)---Caloplaca
85b Ascospores with thin septa, often more than 3-septate; disc K----86

86a Apothecia with weak, soon inapparent margin; apothecia soon convex to globose; paraphyses branched---Micarea
86b Apothecia with prominent, rather persistent margin; disc more or less flat; paraphyses unbranched for most of their length, rarely (in Fellhanera) branched---87

87a Ascus tholus containing a more or less conical, I+ weakly staining axial mass around ocular chamber---88
87b Ascus tholus containing a tubular, I+ strongly staining structure, most distinctly stained in its basal part (except in Mycobilimbia)---92

88a Ascospores fusiform, less than 5 times as long as wide---89
88b Ascospores acicular, generally more than 5 times as long as wide---91

89a Apothecia with brown "lid"-like appendage on the margin---Auriculora
89b Apothecia without such appendage---90

90a Ascus tholus with rounded, I+ weakly staining axial mass around ocular chamber---Megalaria
90b Ascus tholus with pointed, I+ weakly staining axial mass around ocular chamber---Biatora s.l.

91a Excipulum paraplectenchymatic; asci with rounded axial mass---Bacidina
91b Excipulum prosoplectenchymatic; asci with conical axial mass---Bacidia

92a Excipulum with byssoid outer layer---Byssoloma
92b Excipulum smooth outside---93

93a Apothecia mostly under 0.5 mm side, soon convex; exciple paraplectenchymatic---Fellhanera
93b Apothecia usually over 0.5 mm wide, flat; exciple prosoplectenchymatic---94

94a Among mosses on soil; campylidia absent; tubular structure in ascus apex distinctly stained over its whole length---Mycobilimbia
94b On bark; campylidia present or absent; tubular structure in ascus apex widened and less distinct towards the tip---95

95a Ascospores fusiform; campylidia often present---Badimia
95b Ascospores needle-shaped to cylindrical; campylidia absent---Bapalmuia

100a (30) Apothecia yellow to red, K+ dark purple---101
100b Apothecia not yellow to red, K----102

101a Thallus white or pale grey---Brigantiaea
101b Thallus green suffused more or less with yellow---Letrouitia

102a Hymenium inspersed with oil-like droplets; spores single---Megalospora
102b Hymenium clear; spore number per ascus various---103

103a Ascus tholus containing a tubular I+ strongly staining structure; no campylidia present; paraphyses little branched---Bapalmuia
103b Ascus tholus without tubular, I+ structure, often with wide ocular chamber; usually campylidia present; paraphyses strongly branched---104

104a Ascomata with tomentose margin---Lasioloma
104b Ascomata with smooth margin---105

105a Campylidia absent---106
105b Campylidia present---107

106a Growing in rock; ascospores with gelatinous sheet (halo)---Rhizocarpon
106b Growing on organic substrate; ascospores without gelatinous sheet---Schadonia

107a Campylidia consisting of a thalloid tube and a short, brownish "ear"; ocular chamber of ascus wide; excipulum paraplectenchymatic---Sporopodium
107b Campylidia consisting of a large, greyish "ear" sitting directly on the thallus; ocular chamber of ascus wide; excipulum paraplectenchymatic---Calopadia

120a (20, 256) Ascocarps compound, with several, often punctiform discs in usually raised areas which are concolorous with the thallus or differently coloured; ascospores transversely septate only---121
120b Ascocarps simple, with single disc, at age sometimes deformed; ascospores transversely septate or muriform---130

121a Thallus felt-like, greenish---Dichosporidium
121b Thallus with compact upper layer---122

122a Discs arranged in lines, often loosely accumulated---123
122b Discs not arranged in lines, densely accumulated in roundish groups---125

123a Spores dark grey-brown; saxicolous---Sclerophytonomyces
123b Spores hyaline; usually corticolous---124

124a Ascospores with enlarged terminal cells, at least when juvenile---Sclerophyton
124b Ascospores with terminal cells not significantly larger than median cells, also not in juvenile spores---Enterographa

125a Ascocarp discs wider, pruinose, in rounded groups---Syncesia
125b Ascocarp discs punctiform, blackish---126

126a Ascospores bacillar, 3-8-septate, widest above the middle and gradually tapering towards both ends; no red pigment in medulla---Chiodecton
126b Ascospores biclavate, 4-7-septate, with a larger and a smaller swollen part; often with spotted red pigment in medulla---Erythrodecton

130a (120) Ascocarps immersed in a slightly raised thallus wart; hymenium separated from the margin by a split; spores bacillar---Conotrema
130b Ascocarps sessile on smooth thallus; hymenium connected with margin, if present; spores various---131

131a Ascocarps without margin, adnate beneath their whole hymenium; asci broadly clavate to globose, with thick apical dome with large ocular chamber (Arthonia-type); ascospores variously septate, often with one terminal cell much larger than the others---132
131b Ascocarps with distinct, thalloid or lecideine margin, often with constricted base; asci elongate, with thin apical dome with small ocular chamber, often surrounded by small I+ blue ring (Opegrapha-type); ascospores transversely septate only, never with terminal cell much larger than the others---135

132a Hymenium gelatinous, not felt-like; ascocarps clearly distinct---133
132b Hymenium not gelatinous, felt-like; ascocarps clearly distinct---Coniarthonia
132c Hymenium not gelatinous, felt-like; ascocarps scarcely distinct from thallus or asci scattered in (unmodified) thallus---134

133a Ascospores transversely septate only (when discs punctiform and more or less grouped, see Enterographa)---Arthonia
133b Ascospores muriform---Arthothelium

134a Ascospores transversely septate only---Stirtonia
134b Ascospores muriform---Cryptothecia

135a Apothecial margin carbonised throughout, black---136
135b Apothecial margin not carbonised externally, whitish or thalloid---137

136a Ascospores acicular, 3-45-septate; disc permanently black---Bactrospora
136b Ascospores fusiform, 3-19-septate; disc often yellow-pruinose---Cresponea

137a Apothecia with thallus-like margin usually containing algae---138
137b Apothecia biatorine to lecideine, without algae in the margin---142

138a Corticolous---139
138b Saxicolous---141

139a Apothecium margin thin, gradually raising from the thallus; apothecia not constricted at base---Mazosia
139b Apothecium margin thick; apothecia constricted at base---140

140a Thallus P+ yellow (psoromic acid), C----Sigridea
140b Thallus P- (psoromic acid absent or as minor compound), C+ red---141

141a White medulla layer under the black hypothecium---Dirina
1341b Black hypothecium reaching to the substrate and confluent with black hypothallus, when present---Roccellina

142a (137) Ascospores 1-septate; apothecia with strongly constricted base, rarely over 2 mm diam., usually with yellowish colour---Dimerella
142b Ascospores 3-septate; apothecia appressed and large, often over 2 mm diam.---Sagenidiopsis
142b Ascospores 5-7-septate; apothecia sessile with constricted base, not over 1.5 mm wide---Lecanactis

160a (20) Ascospore lumina rounded at maturity; endospore usually I+ violet---161
160b Ascospore lumina edged, at most with lightly rounded edges, without or with scarce endospore; ascospores I-negative---170

161a Hymenium separated from the surrounding thalline margin by a split; in dry state seemingly with a double margin---Thelotrema
161b Hymenium not separated from the margin---162

162a Margin not carbonised; apothecia immersed in the thallus; apothecia without columella---163
162b Margin at least partly carbonised and black; apothecia more or less exerted; apothecia often with carbonised central columella---164

163a Apothecial margin rounded to flat; discs tiny, rarely over 0.5 mm wide---Myriotrema
163b Apothecial margin lacerate, forming slips which cover the disc in part; discs often several mm wide---Thelotrema

164a Apothecia with raised thalline margin, discs invisible, or visible through thallus splits, pale, often white-pruinose---Ocellularia
164b Apothecia exerted above thallus, without thalline margin; discs widely exposed, brownish---165

165a Apothecia compound, with several, often elongated discs level with the margin; ascospores hyaline, transversely septate---Glyphis
165b Apothecia simple---166

166a Ascospores hyaline, muriform---Gyrostomum
166b Ascospores grey, bacillar---Phaeographis pr.p.

170a (160) Paraphyses branched and anastomosing throughout---171
170b Paraphyses unbranched, except sometimes near the tips, or with indistinct transverse connections---173

171a Thallus without bristles; on various substrates ---Gyalideopsis
171b Thallus with white or black bristles or hyphophores; mostly on twigs---172

172a Apothecia with constricted base and prominent margin; bristles usually black; hyphophores absent---Tricharia
172b Apothecia widely adnate and with indistinct margin; bristles usually white, when present; hyphophores often present---Echinoplaca

173a Ascospores acicular, to c. 4 Ám wide---174
173b Ascospores ovoid to fusiform, generally over 4 Ám wide---175

174a Epiphytic; thallus grey; apothecia very elongated, tubular, forming c. 2 mm long stalks, brown---Gomphillus
174b Terrestrial; thallus yellow; apothecia discoid, black---Arthrorhaphis

175a Terrestrial or on rock; apothecia immersed; ascospores grey, ovoid and muriform---Diploschistes
175b Epiphytic, rarely on rock; apothecia sessile or immersed, not immersed when on rock; ascospores various---176

176a Apothecia persistently immersed or level with thallus, with flat disc, often over 1 mm large, often elongate; margin lacerate or not---177
176b Apothecia initially immersed, finally sessile with constricted base, with concave disc, mostly under 1 mm large, always rounded; margin entire or crenate---179

177a Margin inapparent, granular; paraphyses with thin transverse connections; asci I+ pale blue, with thin apex---Phlyctidia
177b Margin lacerate or rounded to flat; paraphyses simple; asci I-negative, with thickened apex---178

178a Margin rounded to flat; discs rounded to elongate, often several mm long---Cyclographina
178b Margin lacerate; discs rounded to slightly elongate---Chroodiscus

179a Apothecia proliferating from their margins and thus forming coralloid-branched structures, greenish; on twigs or leaf margins; ascospores 5-7-septate; hymenium usually absent---Polystroma
179b Apothecia not proliferating---180

180a Apothecia with carbonised excipulum more or less covered by pale pruina or thallus; on mosses or decaying bark or wood; ascospores muriform---Ramonia
180b Apothecia not with carbonised margin---181

181a Hymenium I+ (pale) blue---182
181b Hymenium I---184

182a Photobiont a bluegreen alga---Bryophagus
182b Photobiont Trentepohlia-like---183

183a Spores 8 per ascus, transversely septate or muriform---Gyalecta
183b Spores 8-16 per ascus, transversely septate---Cryptolechia

184a Apothecia pale yellow to orange; on various substrates; ascospores one-septate (NB: for species determination it is important to study pycnidia, which are often found on separate individuals)---Dimerella
184b Apothecia shades of brown; ascospores bacillar-pluriseptate or muriform---Gyalidea

200a (2) Ascospores simple---201
200b Ascospores septate---203

201a Ascospores 16-20 in each ascus---Kalbiana
201b Ascospores 8 in each ascus---202

202a Ascospores thickwalled, often with spines or ridges; paraphyses persistent---Monoblastia
202b Ascospores thinwalled, smooth; paraphyses disappearing in an early stage---Verrucaria

203a Ascospores (finally) brown or grey-brown---204
203b Ascospores persistently colourless---214

204a Ascospore with thin septa and edged lumina---205
204b Ascospore with thick septa and rounded lumina---208

205a Asci ovoid with narrow ocular chamber, much narrower than half of the tholus---206
205b Asci subcylindrical with wide ocular chamber, about half as wide as tholus---207

206a Ascospores with 1-3 transverse septa; ascocarps simple---Mycomicrothelia
206b Ascospores transversely septate to muriform; ascocarps mostly multi-chambered by lateral fusion of ostioles---Mycoporum

207a Ascospores one-septate---Clypeopyrenis
207a Ascospores muriform---Anthracothecium

208a Ascospores one-septate---209
208b Ascospores transversely septate only, with 3 or more septa---210
208c Ascospores muriform---211

209a Ascospores without pigment granules in endospore---Distopyrenis
209b Ascospores with pigment granules in endospore---Granulopyrenis

210a Ascospores three- or more-septate, under 50 Ám long when three-septate---Pyrenula
210b Ascospores three-septate, over 70 Ám long---Architrypethelium

211b Paraphyses indistinct to absent, desintegrating at an early stage; algae in hymenium present---Staurothele
211b Paraphyses persistent; no algae in hymenium---212

212a Spores without longitudinal grooves, usually with prominent median transverse septum---Pyrenula
212b Spores with 2 longitudinal grooves, with prominent median longitudinal septum---Sulcopyrenula

214a (203) Ascospores with (partly) thickened septa and rounded lumina; ascocarps often compound, in extensive pseudostromata---215
214b Ascospores with thin septa and edged lumina; ascocarps usually simple---223

215a Ascospores transversely septate only---216
215b Ascospores muriform---220

216a Thallus poorly developed, indicated by a whitish patch on bark; ascocarps naked at maturity, never aggregated in pseudostromata; confusible with 234b Polymeridium and differing by its scarcely branched paraphyses, which are distorted and winding in preparations---Pseudopyrenula
216b Thallus well developed; ascocarps immersed in thallus or in pseudostromata---217

217a Ostioles free, apical---218
217b Ostioles fused to form a compound ascocarp---Astrothelium

218a Ascospores 1-septate, over 45 Ám long, with needle-shaped crystals in the wall---Megalotremis
218b Ascospores more than 2-septate, often under 45 Ám long, without crystals---219

219a Paraphyses branched and anastomosing; ascus apex with narrow ring surrounding a small ocular chamber; wall thickening of ascospores most pronounced at the edges; spores more than 2-septate---Trypethelium
219b Paraphyses unbranched; ascus apex with a wide apical ring and wide ocular chamber; wall thickening of the ascospore more equal; spores more than 2-septate---Lithothelium

220a (215) Ostiole apical---221
220b Ostiole lateral, free or fused---222

221a Ascocarps in brown, usually shiny pseudostromata containing yellow or orange pigments, K- or K+ red; pseudostroma wall composed of brown, jigsaw puzzle-like hyphae---Bathelium
221b Ascocarps not in brown pseudostromata, or wall not composed of brown, jigsaw puzzle-like hyphae---Laurera

222a Ostioles free---Campylothelium
222b Ostioles fused to other ostioles to form compound ascocarps---Cryptothelium

223a (214) Ascus tip thin, truncate (Trichotheliaceae); paraphyses unbranched---224
223b Ascus tip more or less thickened with an ocular chamber, rounded; paraphyses often branched---227

224a Ascocarps with a subapical whorl of stiff, usually black bristles---Trichothelium
224b Ascocarps without bristles---225

225a Ascospores transversely septate; asci with chitinoid apical ring---Porina
225b Ascospores muriform; asci without chitinoid apical ring, with slight subapical constriction---226

226a Medulla white or pale yellowish---Clathroporina
226b Medulla yellow to orange or brownish---Myeloconis

227a Thallus gelatinous; spores one-septate---Pyrenocollema
227b Thallus not gelatinous; spores variously septate---228

228a Paraphyses indistinct to absent, desintegrating at an early stage; hymenial gelatine I+ reddish---229
228b Paraphyses distinct, persistent; hymenial gelatine I----230

229a Spores transversely septate---Thelidium
229b Spores muriform (if thallus minutely sqamulose to fruticose, see Psoroglaena)---Polyblastia

230a Paraphyses mostly unbranched; macroconidia usually present, cylindrical, septate---Strigula
230b Paraphyses branched, especially above level of asci; macroconidia more or less globose, simple, or lacking---231

231a Ascocarps simple---232
231b Ascocarps multilocular, chambers laterally fused with separate ostioles---238

232a Ascospores transversely septate---233
232b Ascospores muriform---237

233a Ascospores ovoid-fusiform, 1-11-septate, usually over 4 Ám wide---234
233b Ascospores filiform, 5->10-septate, 1.5-2 Ám wide---Celothelium

234a Ascospores ovoid-fusiform, 1-septate, rarely finally 3-septate---235
234b Ascospores fusiform, 3-11-septate, over 4 Ám wide; asci and paraphyses as in Trypethelium; confusible with 216a Pseudopyrenula, and differing by its strongly anastomosing paraphyses, which remain straight and reticulate in preparations---Polymeridium

235a Lower ascospore cell usually the shorter; lichenised; microconidia globose to ellipsoid; macroconidia often present, simple, globose to ellipsoidal; ostiole often lateral---Anisomeridium
235b Lower ascospore cell usually the longer; mostly non-lichenised; microconidia bacillar; macroconidia lacking; ostiole always apical---236

236a Paraphyses slender, without refractive bodies near the septa; asci clavate---Arthopyrenia
236b Paraphyses short-celled, with refractive bodies near the septa; asci obpyriform---Naetrocymbe

237a Asci with indistinct apical thickening; ascospores usually 8 in each ascus; algiferous thallus present (following Harris 1995 with inclusion of Aspidothelium, with an apical disc-like expansion or subapical scales on the perithecia)---Thelenella
237b Asci with pronounced apical thickening with strong ocular chamber (Arthopyrenia-like), ascospores 2 in each ascus in neotropical species; non-lichenized (if lichenized, try #220)---Julella

238a (231) Paraphyses indistinct, with many oil droplets; ascospores transversely septate to muriform; asci obpyriform to obclavate---Mycoporum
238b Paraphyses distinct, without oil droplets; ascospores transversely septate to submuriform---239

239a Ascospores with 1-3 transverse septa only; asci rather cylindrical; paraphyse cell ends with refractive body---Tomasellia
239b Ascospores submuriform, 4 x 2 cells with enlarged end cells; paraphyse cells without refractive bodies---Exiliseptum

251a (2) Paraphyses branched and anastomosing; hymenium I+ red or blue; ascospore lumina not rounded, at most with slightly rounded edges, septa I-negative; asci with rather thin tholus with small ocular chamber often surrounded by a small I+ blue ring---252
251b Paraphyses unbranched except sometimes at the tips or around the asci; hymenium I-negative, rarely I+ pale blue; ascospore lumina often rounded, more or less lentiform, septa often I+ blue or violet; asci usually with thick tholus, completely I-negative---258

252a Ascocarp walls (labiae) conspicuous and carbonised, at least internally---253
252b Ascocarp walls indistinct, not carbonised---256

253a Ascocarps immersed in thallus or with thick thalline cover over carbonized part of margin; hymenium always gelatinous---254
253b Ascocarps exerted with prominent carbonised margin; hymenium gelatinous or occasionally not---255

254a Ascospores with transverse septa only, hyaline; ascocarps immersed in thallus---Enterographa
254b Ascospores with transverse septa only, brown; ascocarps immersed in thallus, very elongate---Platygraphopsis
254c Ascospores muriform, hyaline; ascocarps short and exerted with thick thallus cover---Helminthocarpon
254d Ascocarps variously septate, often brown at maturity; ascocarps level with thallus, with thin thalline margin---Sclerophyton

255a Lirellae with closed or narrowly gaping labiae; asci with I+ blue cap in tip, which extends laterally; spores transversely septate---Opegrapha
255b Like a, but spores muriform---Dictyographa
255c Lirellae usually with wide open disc; asci without or with tiny I+ blue cap in tip; spores transversely septate---Lecanographa

256a Asci narrowly ovoid to subcylindrical, with hardly thickened tip---120
256b Asci ovoid to globose, with strongly thickened tip---257

257a Hymenium not gelatinous; ascospores muriform or transversely septate---Coniarthonia
257b Hymenium gelatinous; ascospores muriform---Arthothelium
257c Hymenium gelatinous; ascospores transversely septate only---Arthonia

258a (251) Ascocarps in stellate or rounded clusters---259
258b Ascocarps single---268

259a Ascospores muriform---260
259b Ascospores transversely septate only---261

260a Ascospores colourless; merocarps with rounded ends---Medusulina
260b Ascospores grey to brown; merocarps with pointed ends---Sarcographina

261a Ascospores colourless; merocarps with rounded ends---Glyphis
261b Ascospores grey to brown; merocarps with pointed ends---Sarcographa

268a Mature ascospores predominantly on top of hymenium, forming a mazaedium---Schistophoron
268b Mature ascospores in the asci, not forming a mazaedium---269

269a Ascospores simple, thinwalled; on wood---Xylographa
269b Ascospores one-septate, with edged lumina---Melaspilea
269c Ascospores many-septate, mostly with lenticular lumina (when mature)---270

270a Ascocarps without lateral exciple, immersed with thin margins level with thallus surface---Fissurina
270b Ascocarps with more or less carbonized lateral exciple, more or less raised with thickened, raised margins---271

271a Paraphyses with warted tips; lirellae variously coloured, C-negative---Acanthothecis
271b Paraphyses with smooth tips; lirellae white, C+ red---Dyplolabia
271b Paraphyses with smooth tips; lirellae variously coloured, C-negative---272

272a Ascospores transversely septate only, with lenticular lumina (when mature)---273
272b Ascospores muriform---274

273a Ascospores colourless---Graphis
273b Ascospores grey to brown---Phaeographis

274a Ascospores colourless, with or without lenticular lumina (when mature)---275
274b Ascospores grey to brown, with lenticular lumina (when mature)---Phaeographina

275a Paraphyses unbranched, also at the tips; ascospore lumina lenticular when mature---Graphina
275b Paraphyses somewhat branched and anastomosing in the epithecium, parallel below; ascospore lumina persistently edged---Cyclographina

330a (3, with conidangia) Conidangia campylidia, with "ear"-shaped, grey or brownish, geotropically directed extension (see also key to foliicolous species, couplet 85 f.f.)---"Pyrenotrichum", 331
330b Conidangia hyphophores, brush-like with widened tip carrying a gelatinous "drop"; usually immixed with longer, sterile hairs---Echinoplaca
330c Conidangia superficial black spots---334
330d Conidangia immersed---not treated

331a Campylidia producing simple, pyriform or short-bacillar conidia---332
331b Campylidia producing septate, filiform conidia---333

332a "Ear"-shaped part short, on top of a short, thalloid cylinder---Sporopodium
332b "Ear"-shaped part large, directly on thallus---Musaespora

333a Campylidia grey, producing conidia without appendages---Calopadia
333b Campylidia brown, producing conidia with appendages (small lateral branchlets)---Badimia

334a Conidia darkbrown, composed of irregularly delimited glomerules of hyphae, c. 10-15 mu diam. Thallus thin, pale grey---Milospium
334b Conidia brown, simple or 2(-4)-celled---Tylophoron
334c "Conidia" brown, obovate and 4-6-celled, being ascospores and originating from asci in indistinctly delimited ascomata---Sporostigma

351a (3, sterile) Thallus leprose, surface entirely sorediate---352
351b Thallus felt-like, of woolly appearance while without cortex and entirely composed of very loose hyphae---354
351c Thallus not leprose or felt-like. Here many usually sorediate or isidiate species would key out, belonging to various groups like Pertusaria, Thelotremataceae, Porina. Only a few selected lowland species are treated here.---357

352a Thallus bright yellow; with diffuse margin---Chrysothrix
352b Thallus shades of pale grey; with diffuse or vaguely lobate margin---353

353a Thallus shades of grey; with diffuse margin---Lepraria
353b Thallus shades of grey; with vaguely lobate margin---Leproloma

354a Thallus not zoned, usually with an abrupt border, often lobed---Crocynia
354b Thallus zoned, i.e. with a differentiated marginal zone, of a paler colour and gradually thinning out---355

355a Thallus bluegreen, without isidia, with filamentose cyanobacteria---Dictyonema
355b Thallus pinkish to greenish, with or without isidia, with green algae---356

356a Thallus margin whitish; thallus greenish, with felty isidia---Dichosporidium
356b Thallus margin blackish; thallus pinkish to greenish, without isidia---Sagenidiopsis

357a (351) Medulla conspicuously coloured, yellow, orange or reddish---358
357b Medulla white---361

358a Medulla completely or partly red or pink; sorediate or isidiate---359
358b Medulla orange or yellow; sorediate---360

359a Medulla with scattered red spots; thallus surrounded by black prothallus and with soralia---Erythrodecton
359b Medulla pink throughout; with glossy, short, clavate isidia; with hypoprotocetraric acid---Ocellularia rhodostroma
359c Medulla red throughout, exposed along the margins---Cryptothecia rubrocincta

360a Thallus greenish, glossy, with scattered soralia-like, yellow spots---Myeloconis
360b Thallus grey, dull, with raised, often dense, yellow soralia---Megalospora "chlorites"

361a With soralia---362
361b With schizidia; forest undergrowth species---364
361c With isidia; only two forest undergrowth species treated---367

362a Thallus C+ red; on well-lit sites---Pertusaria velata
362b Thallus C-negative; on tree trunks in forest---363

363a Soredia fine; with stictic acid (P+ orange, K+ orange)---"Thallotrema"
363b Soredia coarse, in part corticate; with hypoprotocetraric acid (P-, K-)---Myriotrema neofrondosum

364a Schizidia accumulated in groups, which may look soralium-like and may be raised or shortly stalked; with hypoprotocetraric acid (P-, K-)---Myriotrema neofrondosum
364b Schizidia arising single, leaving scattered, round scars on the thallus---365

365a Thallus bluegrey-pruinose; with unknown substance---Myriotrema sp.?
365b Thallus greenish, not pruinose; with various substances---366

366a Schizidia small, less than 0.2 mm wide; with protocetraric acid (P+ red)---Myriotrema parvidiscum
366b Schizidia 0.5-0.6 mm wide; with psoromic acid (P+ yellow, K-)---Ocellularia berkeleyana

367a (361) Isidia cylindrical; with psoromic acid (P+ yellow)---Myriotrema hartii
367b Isidia gradually tapering from the base to the tip, with basal constriction and easily falling off; no lichen substances (P-)---Thelotrema brasiliensis

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