Key to the GENERA OF GRAPHIDACEAE / Key to the corticolous SPECIES OF THELOTREMATACEAE in Costa Rica

Descriptions: Acanthotrema, Ampliotrema, Chapsa, Gyrotrema, Fibrillithecis, Leptotrema, Leucodecton, Melanotrema, Myriotrema, Ocellularia, Ramonia?, Redingeria, Reimnitzia, Stegobolus, Thelotrema

NOTE: The nomenclature follows Frisch et al. (2006); unclear affinities and unpublished names or combinations are in "".

1A Isidia, high papillae, schizidia or soredia present (together with ascocarps; rarely fertile taxa not treated) - - - 2
1B Isidia, high papillae and schizidia absent, only ascocarps present - - - 20

2A Cylindrical isidia or papillae present; chemistry various - - - 3
2B Granular isidia, schizidia or soredia present; psoromic acid present - - - 11

3A Cylindrical isidia present; medulla white or indistinct; ascocarps, spores and chemistry various - - - 4
3B Papillae present, dense, irregular, thick and swollen, ca. 0.2-0.2 mm wide; medulla yellow; ascocarps in ca. 0.5 mm wide warts with carbonized wall, without columella; ascospores 1-2/ascus, transversely septate, ca. 150-200 x 25-35 mu, 15-19 celled; hypoprotocetraric acid present - - - Ocellularia aurulenta

4A Ascocarps with visible discs; ascospores and chemistry various - - - 5
4B Ascocarp discs not visible through the pores, which are either tiny or filled by a columella; ascospores hyaline, transversely septate; stictic acid present - - - 10

5A Ascocarps with round, ca. 0.1-0.2 mm wide pore sometimes showing a pinkish disc; ascospores hyaline and muriform, ca. 4 x 1-2 cells and up to 15 mu long - - - 6
5B Ascocarps with over 0.2 mm wide, variously coloured discs; ascospores hyaline and transversely septate, or grey - - - 7

6A Isidia cylindrical, erect, 0.5-1 mm long and ca. 0.25 mm wide, dark-tipped - - - Myriotrema hartii
6B Isidia cylindrical, often decumbent, 0.5-1 mm long and ca. 0.15 mm wide, uniformly coloured - - - Fibrillithecis insignis

7A Isidia slender and tapering; ascocarps with erect to recurved marginal slips, often over 2 mm wide and more or less stellate; paraphyse tips papillate; ascospores hyaline, ca. 10-14 x 4 mu, 4 celled; no substances - - - Acanthotrema brasilianum
7B Isidia cylindrical or branched; ascocarps with low, uniform margin, more or less wart-like; ascospores hyaline and transversely septate or grey and muriform; with or without chemical substances - - - 8

8A Isidia branched; ascocarp disc yellow (much covered by the margin); ascospores hyaline, transversely septate, ca. 60-90 x 12-14 mu, 17-20 celled; protocetraric acid present - - - "Ampliotrema auratipruinosum"
8B Isidia not branched; ascocarp disc not yellow; ascospores hyaline; chemistry different - - - 9

9A Isidia numerous, becoming decumbent; thallus pale greenish, glossy; ascocarp discs 0.2-05 mm wide, round, pinkish; ascospores hyaline, transversely septate, ca. 18-22 x 6-9 mu, 5-6 celled; psoromic acid present - - - Stegobolus isidiiferus
9B Isidia usually scarce, scattered, erect; thallus bluegreenish, dull; ascocarp disc to 1 mm wide, irregularly lobed, grey; ascospores dark grey, muriform, ca. 15-23 x 9-10 mu, 4-6 x 2 celled; no substance present - - - Reimnitzia santensis

10A Isidia cylindrical, to 0.5 mm tall; ascocarps tiny, immersed in the thallus, not carbonized; ascospores ca. 12 x 5 mu, 5 celled - - - Myriotrema dactyliferum
10B Isidia swollen, ca. 0.1 mm wide and to 0.3 mm tall; ascocarps in raised, 0.4-0.5 mm wide warts, with carbonized excipulum; ascospores ca. 50-65 x 10 mu, 7-9 celled - - - Ocellularia bullata

11A (2) Disc-like, ca. 0.5-1 mm diam., scattered schizidia present; ascocarps with carbonized walls and exposed discs showing radiately arranged, carbonized sterile ridges or warts; ascospores hyaline, 4-celled, , ca. 8-10 x 4-8 mu. - - - Stegobolus berkeleyanus
11B Irregular schizidia, coarse-grained soredia or granular isidia present - - - 12

12A Coarse-grained soredia or granular isidia present; ascocarps in sorediascent warts with o.1 mm wide, round pore, non-carbonized; ascospores hyaline, transversely septate, ca. 18-24 x 6-10 mu, 6-7 celled - - - Myriotrema pulverulentum
12B Schizidia present on top of low warts; ascocarps like in Myriotrema congestum; ascospores hyaline, 10-15 x 6-7 mu, mostly 3-septate - - - Myriotrema neofrondosum

20A (1) Distinct, yellow to red pigment visible on top of the hymenium or in the medulla around the ascocarps - - - 21
19B No such pigment: hymenium top flesh coloured or grey, more or less whitish pruinose; medulla whitish; rarely the proper exciple may be coloured yellowish or reddish - - - 39

21A Ascocarp surface yellow or orange coloured, sometimes only spotwise - - - 22
21B Thallus medulla yellow, orange of red (best visible in thalline margin of ascocarp.) - - - 26

22A Ascocarps with widely exposed, often strongly coloured, columellate disc ca. 1-4 mm wide usually without ripe asci, surrounded by recurved margin divided into slips - - - 23
21B Ascocarp with incurved margin usually largely covering the disc and leaving a narrow pore under 1 mm wide - - - 24

23A Ascocarps strongly coloured, orange to red, disc ca. 2-4 mm wide, with concentrically arranged columellae, usually without ripe asci - - - Gyrotrema sp.
23B Ascocarps predominantly white-pruinose, orange pigment in small spots near the margin, disc ca. 1-2 mm wide, with radiately or irregularly arranged columellae, usually with ripe asci - - - Stegobolus percolumellatus

24A Disc yellow, hardly visible through the pore; hymenium inspersed with oil droplets; ascospores muriform, hyaline or grey; with protocetraric acid or without medullary substance - - - 25
24B Disc rusty red, clearly visible and hardly covered by the margin; hymenium clear; ascospores transversely septate, hyaline, I-negative, ca. 10-14 x 5 mu, 4 celled; with stictic acid - - - Thelotrema neei

25A Ascospores hyaline, muriform, c.24-26 x 12 mu, 6-7 x 1-3 celled; protocetraric acid present - - - Ampliotrema auratum
25A Ascospores grey, muriform, 8/ascus, I+ ?, ca. 22-30 x 11-13 mu, ca. 8 x 3 celled; no medullary substances present - - - "Ocellularia" panamensis

26A Medulla completely coloured; ascocarps in raised warts, with carbonized margin; ascospores hyaline, transversely septate; medullary substances present or not - - - 27
26B Colour restricted to scattered red dots in the medulla; ascocarps immersed with tiny, 0.1 mm wide pore, not carbonized; ascospores brown, muriform, ca. 20-28 x 9-11 mu, 4-6 x 1-3 celled, uniseriate; no medullary substances - - - Leptotrema wightii

27A Medulla yellow to orange - - - 28
27B Medulla red or pink - - - 32

28A Ascospores up to 70 mu long, usually 8/ascus; cinchonarum unknown substance present - - - 29
28B Ascospores over (70-)100 mu long, 1-4/ascus; hypoprotocetraric acid or no medullary lichen substance present - - - 30

29A Ascocarps with strong columella; ascospores ca. 24-70 x 6-12 mu, ca. 7-18 celled - - - Ocellularia cavata
29A Ascocarps without columella; ascospores ca. 18-20 x 5-7 mu, 5-7 celled - - - Ocellularia crocea

30A Ascocarps without columella; hypoprotocetraric acid present - - - 31
30B Ascocarps with columella; ascospores 2-4/ascus, I+ dark violet, ca. 180-200 x 18-22 mu, ca. 35-50 celled; medullary lichen substances absent - - - Ocellularia xanthostroma

31A Thallus with dense, ca. 0.1-0.2 mm wide papillae, easily rubbed off and exposing the yellow medulla; ascospores 1-2/ascus, ca. 150-200 x 25-35 mu, 15-19 celled - - - Ocellularia aurulenta
31B Thallus smooth, not easily exposing the yellow medulla; ascospores 4/ascus, ca. 80-150 x 12-20 mu, 15-30 celled - - - Ocellularia fecunda

32A Medulla red; ascocarp with (weak) columella; ascospores 1-2/ascus, I+ dark violet?, ca. 70-150 x 15-20 mu, ca. 24-30 celled; medullary lichen substances absent - - - Ocellularia mordenii
32A Medulla pink to pale red; ascocarp without columella; ascospores 1/ascus, ca. (90-)150-270 x (20-)25-40 mu, ca. 26-36 celled; hypoprotocetraric acid present - - - Ocellularia rhodostroma

39A (20) Ascocarp margin divided into (usually few) erect, incurved or recurved slips, showing the smooth or ridged disc - - - 40
39B Ascocarp margin entire, erect and showing the disc or flat to incurved and leaving a small pore - - - 70

40A Ascocarp disc smooth without sterile ridges or knobs - - - 41
40B Ascocarp disc with sterile knob (columella) or ridges (actinoid columella) - - - 60

41A Ascocarps with conspicuous, incurved proper excipulum - - - 42
41B Ascocarps without clearly visible proper excipulum - - - 44

42A Ascospores grey, transversely septate - - - Chapsa platycarpa
42B Ascospores hyaline, muriform - - - "Chapsa cruentata"

44A Ascospores hyaline, transversely septate or muriform, 1-8/ascus - - - 45
44B Ascocarps grey, muriform, 2/ascus, ca. 105-120 x 22-26 mu - - - Chapsa stellata

45A Ascocarps ca. 1.5-3 mm wide - - - 46
45B Ascocarps up to 1 mm wide - - - 47

46A Ascocarps stellate; paraphyse tips warty; hymenium 45-70 mu high; ascospores transversely septate, I-negative, ca. 10-14 x 4-5 mu, 4 celled; medullary substances absent - - - Acanthotrema brasiliana
46B Ascocarps rounded; paraphyse tips not warty; hymenium ca. 150-250 mu high; ascospores 2-4/ascus, I+ blue, 60-120 x 10-15 mu, 15-20 celled; stictic acid present - - - "Chapsa sublilacina"

47A Ascospores I+ bluish; stictic acid present or absent - - - 48
47B Ascospores I-negative; lichen substances absent - - - 51

48A Ascospores muriform, 4-8/ascus, ca. 12 x 6 mu, 2-1 x 1-2 celled; lichen substances absent - - - "Chapsa hiata"
48B Ascospores muriform, 1/ascus, ca. 160-180 x 35 mu, ca. 50 x 15 cells; lichen substances absent - - - "Chapsa perdissuta"
48B Ascospores transversely septate; stictic acid present - - - 49

49A Ascocarps with inner excipulum separated from the thalline margin and largely covering the disc; ascospores ca. 16-20 x 5 mu, ca. 8 celled - - - "Chapsa conglomerata"
49B Ascocarps with indistinct inner excipulum - - - 50

50A Ascocarps to ca. 1 mm wide, with margin of few erect to recurved slips; ascospores ca. 16-20 x 5 mu, 6 celled - - - "Chapsa dilatata"
50B Ascocarps 0.3-0.6 mm wide, with margin of few, often not distinctly separated slips or crumbling apically; ascospores ca. 15-18 x 5-6 mu, 6-8 celled - - - "Chapsa pseudoschizostoma"

51A Thallus oily, dark greenish to brownish - - - 52
51B Thallus not oily, pale greenish grey - - - 53

52A Ascocarps level with the thallus, rounded and ca. 0.2-0.8 mm wide, with fully exposed disc surrounded by few erect to recurved, thin and easily breaking marginal slips; ascospores ca. 14-16 x 3-4 mu, 6 celled - - - Chapsa platycarpella
52B Ascocarps immersed in the thallus, often triangular, ca. 0.5 mm wide, with margin of usually three incurved to erect slips; ascospores ca. 15 x 6 mu, 4 celled - - - Thelotrema dissutum

53A Ascospores transversely septate - - - 54
53B Ascospores muriform - - - 236

54A Thallus epiphloeodal or endophloeodal; ascocarps ca. 0.3-0.7(-1.0) mm wide, occasionally with regenerated hymenia and double margins; ascospores ca. 14-25 x 4-5 mu, 6-8 celled - - - Chapsa alborosella
54B Thallus endophloeodal; ascocarps ca. 0.2-0.4 mm wide; ascospores small, ca. 4.5 x 2.5 mu, 2 celled - - - Chapsa "bicellularis"

60A (40) Ascospores (very) pale grey to brownish grey, (pale) brown when old - - - 61
60B Ascospores colourless, remaining so when old - - - 62

61A Thallus UV-; ascospores pale grey, transversely septate, ca. (9-)14-20(-30) x 4-8 mu, 4-6(-12) celled; psoromic acid present - - - Stegobolus auberianus
61B Thallus UV+ yellow; ascospores pale grey to grey-brown, muriform, ca. 12 x 7-8 mu, 3-6 x 1-2 celled; lichexanthone present - - - Stegobolus metaphoricus

62A Psoromic acid present; ascospores transversely septate, ca. 12-24 x 5-6 mu, 5-6 celled - - - Stegobolus granulosus
62B Medullary substances absent; ascospores transversely septate, ca. 25 x 6 mu, ca. 11 celled - - - Stegobolus emersus?

70A (40) Papillae or ridges of sterile tissue (columella) present on the ascocarp disc, at least in some ascocarps - - - 71
70B Columella absent in all ascocarps - - - 140

71A Ascocarps with carbonized tissue in the wall and/or in the columella; this usually visible as a distinct, central papilla - - - 72
71B Ascocarps without carbonized tissue; columellae scarce, usually as pale ridges on the disc - - - 125

72A Ascospores pale grey to brownish grey, brown when old - - - 73
72B Ascospores colourless, remaining so when old - - - 79

73A Ascospores transversely septate - - - 74
73B Ascospores muriform - - - 77

74A Ascocarps with over 0.5 mm wide, irregular pore - - - 75
74B Ascocarps with less than 0.5 mm wide, round or somewhat elongate pore - - - 76

75A Psoromic acid present; ascospores ca. (9-)14-20(-30) x 4-8 mu, 4-6(-12) celled - - - Stegobolus auberianus
75B Hypoprotocetraric acid with or without lichexanthone present; ascospores ca. 20 x 10 mu, 4 celled - - - Redingeria glyphica

76A Hypoprotocetaric acid present; ascospores ca. 15 x 8 mu, 4 celled - - - Redingeria leiostoma
76B No lichen substance present; ascospores ca. 16-18 x 10 mu, 4 celled - - - Melanotrema meiospermum

77A Ascocarps with over 0.4 mm wide, irregular pore; lichexanthone present; ascospores a. 12 x 7-8 mu, 3-6 x 1-2 celled - - - Stegobolus metaphoricus
77B Ascocarps with 0.2-0.5 mm wide, round pore - - - 78

78A Psoromic acid present; ascospores ca. 12 x 7-9 mu, 2-4 x 2 celled - - - Stegobolus fissus
78B Lichexanthone present; ascospores ca. 10 x 6 mu, 2-4 x 2 celled - - - Stegobolus metaphoricus

79A (72) Ascospores transversely septate - - - 80
79B Ascospores muriform - - - 110

80A Ascospores over 90 mu long - - - 81
80B Ascospores under 70 mu long - - - 83

81A Thallus surface smooth; cinchonarum unknown substance present; ascospores 1-2/ascus, ca. 120-160 x 12 mu, ca. 15-20 celled - - - Ocellularia rhabdospora
81B Thallus surface fine warty; psoromic acid or no substance present - - - 82

82A No lichen substance present; ascospores ca. 4/ascus, ca. 140-250 x 15-20(-30) mu, ca. 30 celled - - - Ocellularia dolichotata
82B Psoromic acid present; ascospores ca. 2/ascus, ca. 90-100 x 15-16 mu, ca. 20 celled - - - Ocellularia ripleyi

83A Ascocarp pore wide, over 5 mm wide in fully developed ascocarps; disc usually with more than one sterile knob or with sterile ridges - - - 84
83B Ascocarp pore narrow, 0.1-0.2(-0.5) mm wide; disc with single central sterile knob - - - 92

84A Psoromic acid present - - - 85
84B Hypoprotocetraric acid or no lichen substance present - - - 89

85A Ascospores ca. 8-10 x 4-8 mu, 4 celled; discoid schizidia usually present - - - Stegobolus berkeleyanus
85B Ascospores usually over 12 mu long and more than 4-celled; discoid schizidia absent - - - 86

86A Ascospores ca. 25-35 mu long, 8-13 celled - - - Stegobolus emersus
86B Ascospores 12-25 mu long, 5-6 celled - - - 87

87A Ascocarp disc without distinct knobs, but radiately fissured with fine, somewhat carbonized ridges - - - Stegobolus schizostomus
87B Ascocarp discs with distinct, carbonized knobs, usually a large, central one and more or less smaller, periferal ones - - - 88

88A Ascocarp margin erect to recurved, more or less split in wide slips, with wider, non-annulate pore and lower columella finally surrounded by radiating, smaller columellae - - - Stegobolus granulosus
88B Ascocarp margin erect, not split, with narrow, often anulate pore and single, entire, conical columella - - - Stegobolus subcavatus

89A Ascospores 3-4 celled, ca. 15 x 6 mu; hypoprotocetraric acid present - - - Stegobolus actinotus
89B Ascospores ca. 11 celled, ca. 25 x 6 mu; no lichen substances present - - - Stegobolus emersus

92A Ascocarp warts small, up to 0.5(-0.7) mm wide, low and often hardly raised above the thallus - - - 93
92B Ascocarp warts larger, around 1.0 mm wide, distinctly raised - - - 99

93A Ascocarp warts low, often hardly raised above the thallus; psoromic or protocetraric acid present or no lichen substance present - - - 94
93B Ascocarp warts distinctly raised; cinchonarum unknown or other unknown substance present - - - 98

94A Thallus minutely verrucose - - - 95
94B Thallus smooth - - - 96

95A Psoromic acid present; ascospores ca. 25-30 x 8 mu, 6-8 celled; ascocarp warts 0.3-0.5 mm wide, columella usually present - - - Ocellularia antillensis
95B Psoromic acid present; ascospores ca. 17-20 x 7-9 mu, 6-8 celled; ascocarp warts 0.5-0.7 mm wide; columella absent or small - - - Ocellularia umbilicata

96A Psoromic acid present; ascospores ca. 15 x 6 mu, ca. 6-celled - - - Ocellularia terebrata
96B Psoromic acid absent - - - 97

97A Protocetraric acid present; ascospores 18-28(-45) x 7-8(-10) mu, 5-8(-10) celled - - - Ocellularia perforata
97B No lichen substance present; ascospores ca. 20-30(-35) x 6-8 mu, (7-)8-10 celled - - - Ocellularia papillata

98A Ascocarps with 0.4-0.7 mm wide pore and white-tipped columella; cinchonarum unknown substance present; ascospores ca. 12-15 x 5-6 mu, 4-6 celled - - - Stegobolus subemersus
98B Ascocarps with 0.1-0.2 mm wide pore and black columella; other unknown substance present; ascospores ca. 40 x 8 mu, ca. 12 celled - - - Ocellularia cf. viridis

99A (92) Ascocarp pores 0.2-0.5 mm wide; ascocarps weakly raised; lichen substances absent; thallus usually endophloeodal; ascospores ca. 18-20 x 6-7 mu, 6 celled - - - Melanotrema platystomum
99B Ascocarp pores 0.1-0.2(-0.3) mm wide; ascocarps weakly or strongly raised - - - 100

100A Ascocarps immersed in the thallus to slightly raised - - - 101
100B Ascocarps in strongly raised to basally constricted warts - - - 102

101A Psoromic acid present; hymenium (80-)100-150(-180) mu high; ascospores ca. 18-35 x (6-)8-9 mu, 6-10 celled - - - Ocellularia calvescens
101B No lichen substance present; hymenium 80-90 mu high; ascospores ca. 14-19 x 5-6 mu, 5-6 celled - - - Ocellularia landronii

102A Ascocarp warts basally constricted; cinchonarum unknown substance present; ascospores ca. 24-70 x 6-12 mu, ca. 7-18 celled - - - Ocellularia cavata
102B Ascocarp warts not basally constricted; psoromic acid or other unknown substance present - - - 103

103A Ascocarps annulate; columella tip partly carbonized; psoromic acid present; ascospores ca. 8-22 x 4-8 mu, 5-6 celled - - - Stegobolus subcavatus
103B Ascocarps not annulate; columella uniformly carbonized - - - 104

104A Psoromic acid present; thallus epiphloeodal; ascospores ca. 16-18 x 6 mu, 6-8 celled - - - Ocellularia terebrata
104B Psoromic acid absent; ascospores ca. 14-20 x 7-8 mu, ca. 5-6 celled - - - Stegobolus reconditus

110A (79) Ascospores I- - - - 111
110B Ascospores I+ dark- to brown-violet - - - 112

111A Ascocarp warts up to 0.3 mm wide, pore ca. 0.05 mm wide not showing the narrow columella; ascospores ca. 13-30 x 6-12 mu, 4-6 x 2 celled - - - "Ocellularia" clandestina
111B Ascocarp warts to 0.5-0.7 mm wide, pore 0.2-0.5 mm wide showing the wide, flat-topped columella, margin often with splits; ascospores ca. 25-35 x 10-18 mu, 6-10 x 2-4 celled - - - "Thelotrema" cf. leucomelanum

112A Ascospores under 50 mu long, 4/ascus, ca. 24-50 x 10-16 mu, 7-10 x 2-4 celled; psoromic acid present - - - Ocellularia conformis
112B Ascospores over 50 mu long, 1-2/ascus; psoromic acid present or absent - - - 115

115A Ascocarps with 0.1-0.5 mm wide pore, without or with rudimentary columella; psoromic acid present; ascospores 2/ascus, ca. 100-160 x 30-40 mu - - - Ocellularia maxima
115B Ascocarps with 0.1-0.2 mm wide pore, with well developed columella; psoromic acid present or absent - - - 116

116A Ascospores under 150 mu long, 1-2/ascus; hymenium ca. 200 mu high - - - 117
116B Ascospores over 150 mu long, 1/ascus; hymenium ca. 400 mu high - - - 118

117A Thallus minutely warty, uniformly coloured; psoromic acid present; ascospores 2/ascus, ca. 85-125 x 28-40 mu - - - Ocellularia interposita
117B Thallus smooth, usually with white dots; protocetraric acid present; ascospores 1-2/ascus, ca. 90-110 x 30 mu, 20-25 x 7-9 celled - - - Ocellularia "praestantoides"

118A Columella usually visible through the pore; unknown lichen substance present; ascospores ca. 250-300 x 30 mu - - - Ocellularia praestans
118B Columella not visible through the narrow pore; stictic acd agg. present; ascospores ca. 450-600 x 40-50 mu, ca. 200 x 15 celled, apiculate - - - Ocellularia subpraestans

125A (71) Ascospores pale grey to brownish grey, brown when old, muriform - - - 126
125B Ascospores colourless, remaining so when old, transversely septate or muriform - - - 129

126A Ascocarps persistently immersed in the thallus, often with central papilla; thallus with columnar structure due to vertically arranged crystal accumulations (best visible in fracture) - - - 127
126B Ascocarps sooner or later raised, in thallus warts with thick margins and sometimes sterile pale ridges on the disc; thallus without columnar structure - - - 128

127A Psoromic acid present; ascospores ca. 20 x 10 mu, 6 x 2 celled - - - Myriotrema "diplocolumnaris"
127B Protocetraric acid present; ascospores ca. 18-20 x 10 mu, 6 x 2-3 celled - - - Myriotrema laeviusculum

128A Protocetraric acid present; ascospores 25-35 x 12-15 mu, 6-10 x 2-3 celled - - - Ocellularia bahiana
128B Lichen substances absent; ascospores 25-35 x 12-13 mu, 6-8 x 2-3 celled - - - Myriotrema urceolare

129A Ascocarps to 0.5 mm wide; free inner excipulum ring often visible - - - 130
129B Ascocarps over 0.5 mm wide; no free inner excipulum ring visible - - - 131

130A Ascocarps with wide, 0.1-0.5 mm wide pore; psoromic acid present; ascospores 8/ascus, I+ pale blue, ca. 14-18 x 5 mu, 4-6 celled - - - Myriotrema costaricense
130B Ascocarps with narrow, 0.1-0.2 mm wide pore; hypoprotocetraric acid with or without lichexanthone present; ascospores 8/ascus, I+ blue-violet/dark violet, ca. 12-20 x 7 mu, 4-6 x 1-2 celled - - - Myriotrema myrioporoides

131A Ascocarps 0.5-1 mm wide; ascospores transversely septate, I+ dark violet to dark blue-violet - - - 132
131B Ascocarps up to 3 mm wide, with swollen margin; ascospores transversely septate or muriform; I+ (pale) bluish - - - 134

132A Thallus cortex not filmy; protocetraric acid present; ascospores ca. 20-28 x 6-8 mu, 7-8 celled - - - Ocellularia mauritiana
132B Thallus cortex filmy - - - 133

133A Lichen substances absent; ascospores ca. 16-23 x 6-8 mu, 5-8 celled - - - Ocellularia barroensis
133B Psoromic acid present; ascospores ca. 25 x 8 mu, 8 celled - - - Ocellularia "psorbarroensis"
133C Protocetraric acid present; ascospores ca. 30 x 9 mu, 10 celled - - - Ocellularia "subbarroensis"

134A Ascospores transversely septate, ca. 14-22 x 5-7 mu, 4-5 celled; psoromic acid present - - - Stegobolus anamorphus
134B Ascospores ca. 12-20 x 7-9 mu, 4-8 x 1-2 celled; psoromic acid present or absent - - - Stegobolus wrightii

140A (70) Ascocarps with carbonized tissue in the margin - - - 141
140B Ascocarps without carbonized tissue - - - 160

141A Ascocarp wall carbonized marginally and below the hymenium; stictic or psoromic acids present; ascospores hyaline, muriform, 4-8/ascus, I-, ca. 60-75 x 20-25 mu, ca. 20 x 6-7 celled, with rather thin septa; not in Thelotremataceae - - - Ramonia sp.?
141B Ascocarp wall carbonized marginally only, in a thicker or thinner ring - - - 142

142A Hymenium inspersed with ca. 1-3 mu wide oily droplets; ascocarp pore 0.2-0.4 mm wide; protocetraric acid present; ascospores hyaline, transversely septate, ca. 4/ascus, I+ violet, ca. 25 x 9 mu, ca. 8 celled - - - Ampliotrema amplior
142B Hymenium clear - - - 143

143A Ascospores grey, muriform, 1-2/ascus, I-, ca. 160-190 x 35-40 mu; hypoprotocetrarc acid present - - - Ocellularia chiriquiensis
143B Ascospores hyaline - - - 144

144A Ascospores transversely septate - - - 145
144B Ascospores muriform - - - 150

145A Ascocarp warts basally constricted with sunken pore; ascospores over 150 mu long, 1(-2)/ascus, ca. 200-300 x 35-40 mu, ca. 22-30 celled; hypoprotocetraric acid present - - - Ocellularia domingensis
145B Ascocarp warts not basally constricted, pore not sunken; ascospores under 60 mu long, 8/ascus - - - 146

146A Ascocarp warts strongly raised with 0.1-0.3 mm wide pores; protocetraric acid present; ascospores ca. 50 x 12 mu, 12-15 celled - - - Ocellularia dactyliza
146B Ascocarp warts low, with 0.1-0.2 mm wide pored; protocetraric acid absent - - - 147

147A Ascocarp warts 0.5-1.4 mm wide; psoromic acid present - - - 148
147B Ascocarp warts 0.4-0.6 mm wide; cinchonarum unknown substance present; hymenium ca. 75-85 mu high; ascospores ca. 18-22 x 6 mu, 5-6 celled - - - Ocellularia decolorata

148A Ascocarp warts 0.5-1.0 mm wide; ascospores ca. 18-35 x (6-)8-9 mu, 6-10 celled - - - Ocellularia calvescens
148B Ascocarp warts 0.7-1.4 mm wide; ascospores ca. 12 x 4 mu, 4 celled - - - Fibrillithecis pachystoma

150A (144) Ascocarp warts 1.5-2.0 mm wide; ascospores over 100 mu long, 1-2/ascus, (ca. 100-160 x 30-40 mu); psoromic acid present - - - Ocellularia maxima
150B Ascocarp warts 0.5-1.0 mm wide; ascospores under 50 mu long, 8/ascus - - - 151

151A Ascocarps in prominent warts; ascospores I+ blue, ca. 30-40 x 12-15 mu, ca. 8-10 x 1-2 celled; psoromic acid present - - - Ocellularia carassensis
151B Ascocarps immersed in the thallus or slightly raised; ascospores I-negative, ca. 25-30 x 12 mu, 4-6 x 2 celled; stictic acid present - - - Ocellularia cf. erumpens

160A (140) Ascocarps with double margin (inner (proper) excipulum in at least some ascocarps forming a rim around the disc, separate from the thalline margin by a split) - - - 161
160B Ascocarps without double margin (inner excipulum not visible without sectioning, or not or only partly separated from the thalline margin) - - - 190

161A Ascospores grey to brown - - - 162
161B Ascospores hyaline - - - 170
161C Ascospores absent, although ascocarps frequent, see - - - Thelotrema refertum

162A Ascospores transversely septate, ca. 45-80(-100) x 8-15 mu, ca. 12-16(-24) celled; lichen substances absent - - - Thelotrema pachysporum
162B Ascospores muriform - - - 163

163A Ascospores over 50 mu long - - - 164
163B Ascospores up to 30 mu long - - - 165

164A Thallus epiphloeodal, with hypoprotocetraric acid; hymenium ca. 300 mu high; ascospores ca. 150-210 x 33-36 mu - - - Thelotrema hypoprotocetraricum
164B Thallus endophloeodal, without lichen substances; hymenium ca. 150 mu high; ascospores ca. 45-120 x 17-30 mu, ca. 6-30 x 1-8 celled - - - Thelotrema monosporum

165A Ascospores under 20 mu long; ascocarps often in groups; stictic acid major substance (ascospores ca. 12-18 x 6-10 mu, 4-6 x 1-3 celled) - - - Leucodecton glaucescens
165B Ascocarps 20-30 mu long; ascocarps regularly scattered; norstictic acid major substance, stictic acid minor substance - - - 166

166A Thallus with columnar crystal aggregates, strongly fissured; ascospores ca. 20-30 x 10-14 mu, ca. 6-10 x 3 celled - - - Leucodecton occultum
166B Thallus without columnar structure, continuous; ascospores ca. 26 x 12 mu, 6 x 1-2 celled - - - Leucodecton sp. 1

170A (160) Ascospores transversely septate - - - 171
170B Ascospores muriform - - - 180

171A Ascocarps immersed in the thallus, to ca. 0.2 mm wide; hypoprotocetraric acid present - - - 172
171B Ascocarps finally raised in warts, usually over 0.5 mm wide; hypoprotocetraric or other lichen substances present - - - 173

172A Thallus with dull surface; double excipulum regularly visible; ascospores ca. 10-12 x 5-6 mu, 3-4 celled - - - Myriotrema glauculum
172B Thallus with shiny surface; double excipulum rarely visible; ascospores ca. 12-24 x 5-8 mu, 4-6 celled - - - Myriotrema microporellum

173A Ascospores ca. 40-100 x 10-15 mu, ca. 12-25 celled; stictic acid present - - - Thelotrema porinoides
173B Ascospores under 35 mu long, 4-9 celled; stictic acid present or absent - - - 174

174A Ascocarp pores ca. 0.1 mm wide, filled by inner excipulum and scarcely visible, disc invisible; hypoprotocetraric acid present; ascospores 24-35 x 8-9 mu, 5-9 celled - - - Thelotrema refertum
174B Ascocarp pores over 0.1 mm wide, with disc visible inside; hypoprotocetraric acid present or absent - - - 175

175A Ascocarps with dark rusty coloured, sometimes white-powdered disc; stictic acid present; ascospores I-negative, ca. 10-14 x 5 mu, 4 celled - - - Thelotrema neei
175B Ascocarps with pale grey or pinkish disc; ascospores I+ (pale) blue - - - 176

176A Ascocarps with 0.1-0.2 mm wide, round pore; hypoprotocetraric acid present; ascospores I+ blue?, ca. 18 x 8 mu, 4 celled - - - Myriotrema congestum
176B Ascocarps with 0.1-0.5 mm wide, round to edgy pore; psoromic acid present; ascospores I+ pale blue, ca. 14-18 x 5 mu, 4-6 celled - - - Myriotrema costaricense

180A (170) Ascocarps over 0.5 mm wide; ascospores mostly over 50 mu long (except Thelotrema expallescens with spores 15 mu!) - - - 181
180B Ascocarps up to 0.5 mm wide; ascospores under 30 mu long - - - 185

181A Ascospores 8/ascus, I-negative, ca. 15 x 7 mu, ca. 4 x 1-2 celled; stictic acid present - - - Thelotrema expallescens
181B Ascospores up to 4/ascus, I+ or I-, over 40 mu long; stictic acid absent - - - 182

182A Ascocarps all in distinct warts; ascospores I-negative, ca. 50-110 x 20 mu, ca. 17 x 3-4 celled; no lichen substance present - - - Thelotrema lepadinum
182B Ascocarps immersed in the thallus to slightly raised; ascospores I+ bluish; with or without lichen substances - - - 183

183A Ascospores ca. 60-65 x 25-30 mu, ca. 14 x 5 celled, -4/ascus; psoromic acid present - - - Thelotrema cryptotrema
183B Ascospores often over 90 mu long, 1/ascus; psoromic acid absent - - - 184

184A Ascospores ca. 150 x 30 mu; lichen substances absent - - - "Chapsa conveniens"
184B Ascospores ca. 100-220 x 15-40 mu; hypoprotocetraric acid present - - - Thelotrema occlusum

185A Ascospores ca. 45 x 14 mu, ca. 16 x 4 celled, I-negative, with thin septa; psoromic acid present - - - Myriotrema "nicoyense"
185B Ascospores up to 30 mu long, with thickened septa, I+ or I-; psoromic acid present or absent - - - 186

186A Ascospores I-negative; stictic acid present - - - 187
186B Ascospores I+ blue; stictic acid absent - - - 188

187A Ascospores ca. 12-15 x 6 mu; ascocarp pores round to elongate, 0.1-0.3 mm wide; thallus not glossy - - - Thelotrema expallescens
187B Ascospores ca. 25 x 12 mu, 10 x 4 celled; ascocarp pores round, 0.1-0.15 mm wide; thallus glossy - - - Myriotrema myriocarpum

188A Ascocarps finally raised and basally constricted; psoromic acid present; ascospores ca. 13-15 x 7 mu, 4 x 1-2 celled - - - Myriotrema concretum
188B Ascocarps, when raised, without basal constriction; hypoprotocetraric acid present, often with lichexanthone; ascospores ca. 12-20 x 7 mu, 4-6 x 1-2 celled - - - Myriotrema myrioporoides

190A (160) Ascospores grey to brown - - - 191
190B Ascospores hyaline - - - 210

191A Ascospores transversely septate, 8/ascus, ca. 10-12 x 4-5 mu, 2-3 celled; lichen substances absent; ascocarps immersed or semi-emersed, ca. 0.5-0.7 mm wide with 0.2-0.3 mm wide, round or elongate pore - - - Myriotrema vulcani
191B Ascospores muriform - - - 192

192A Ascocarp pore tiny, ca. 0.05 mm wide; stictic acid mostly present - - - 193
192B Ascocarp pore wider, usually becoming over 0.2 mm wide; stictic acid absent - - - 200

193A Thallus not columnar; ascocarps immersed in the thallus or indistinct warts - - - 194
193B Thallus with columnar structure due to vertically arranged crystal masses; ascocarps immersed in the thallus or very slightly raised - - - 195

194A Thallus cortex somewhat filmy; ascocarps immersed in the thallus; hymenium ca. 100 mu high; ascospores 8/ascus, oval, ca. 28-30 x 12 mu, ca. 10 x 3 celled - - - Myriotrema trypaneoides
194B Thallus cortex not filmy; ascocarps in ca. 0.4-0.6 mm wide, low warts; hymenium ca. 300 mu high; ascospores 8/ascus, ca. 25-30 x 18-20 mu, ca. 8 x 4-5 celled - - - Leucodecton sp. 2

195A Thallus (usually) with red spots in the medulla; lichen substances absent; ascospores 8/ascus, ca. 20-28 x 9-11 mu, 4-6 x 1-3 celled, uniseriate - - - Leptotrema wightii
195B Thallus without red spots; stictic acid present - - - 196

196A Ascospores up to 8/ascus, ca. 25-32 x 16-18 mu, ca. 6-8 x 3-4 celled; hymenium clear - - - Leucodecton compunctum
196B Ascospores 4/ascus, ca. 40-80 x 18-30 mu; hymenium clear - - - "Leucodecton deceptum"
196C Ascospores 1-2/ascus, ca. 90-140 x 25-30 mu, ca. 40 x 6 celled; hymenium finely guttulate - - - "Leucodecton reclusum"

200A (192) Hymenium guttulate; ascospores 2/ascus, ca. 100 x 35 mu, 20 x 8 celled; virensic acid present (probably better included in Phaeographis) - - - Thelotrema spondaicum
200B Hymenium clear; ascospores up to 8/ascus, under 40 mu long - - - 201

201A Ascocarps in ca. 0.5-1.0 mm wide warts; ascospores clavate, 25-35 x 12-15 mu, 6-10 x 2-3 celled - - - 202
201B Ascocarps immersed in the thallus or only slightly raised; ascospores up to 25 mu long - - - 203

202A Protocetraric acid present - - - Ocellularia bahiana
202B Lichen substances absent - - - Myriotrema urceolare

203A Ascocarps with 0.05-0.2 mm wide, round pore sometimes showing a slender columella, sometimes showing a slender columella; hymenium ca. 240 mu high; ascospores ca. 20 x 10 mu, 6 x 2 celled; psoromic acid present - - - Myriotrema "diplocolumnaris"
203B Ascocarps with fully exposed, 0.5-1 mm wide, irregularly lobed, grey disc; hymenium ca. 75-130 mu; ascospores ca. 15-23 x 9-10 mu, 4-6 x 2 celled; lichen substances absent - - - Reimnitzia santensis

210A (190) Ascospores transversely septate - - - 211
210B Ascospores muriform - - - 230

211A Ascospores I-negative; lichen substances absent - - - 212
211B Ascospores I+ blue to dark blue-violet; lichen substances present or absent - - - 214

212A Thallus epiphloeodal, distinct; ascocarps with crumbling thalline margin and rounded, pinkish disc surrounded by a low, white excipular ring; ascospores ca. 24 x 7 mu, 9-10 celled - - - "Chapsa rotunda"
212B Thallus endophloeodal er evanescent; ascocarps without crumbling margin - - - 213

213A Ascocarp disc edgy, ca. 0.5 mm wide, pinkish; ascospores ca. 30 x 6 mu, ca. 10 celled - - - Chapsa cinchonarum
213B Ascocarp disc ca. 0.2 x 0.2-0.5 mm, white; ascospores ca. 18 x 6 mu, ca. 6 x 1-2 celled - - - Chapsa kalbii?

214A Ascocarps immersed in the thallus - - - 215
214B Ascocarps in raised thallus warts - - - 222

215A Ascocarps with tiny, to 0.1 mm wide pore without raised margin - - - 216
215B Ascocarps more widely opened with visible disc; ascocarp margin raised, apically more or less crumbling or sorediate - - - 221

216A Thallus dull, with a blue-greenish tinge or finely warty; psoromic acid present - - - 217
216B Thallus slightly glossy, pale greenish grey, smooth; psoromic acid present or absent - - - 218

217A Thallus blue-greenish, smooth; ascospores ca. 8 x 3 mu, 3-4 celled - - - Myriotrema myriotremoides
217B Thallus whitish, finely warty; ascospores ca. 16 x 3-4 mu, 2(-3) celled - - - Myriotrema uniseptatum

218A Ascospores ca. 9-celled, ca. 24-27 x 9 mu; hymenium 120 mu high; psoromic acid present - - - Ocellularia minutula
218B Ascospores 4(-5) celled; hymenium 60-80 mu; psoromic acid present or absent - - - 219

219A Ascospores up to 12 mu long; lichen substances present - - - 220
219B Ascospores ca. 16-18 x 5-6 mu; lichen substances absent - - - Myriotrema album

220A Olivacea unknown substance present; ascospores ca. 6-12 x 4-6 mu - - - Myriotrema olivaceum
220B Psoromic acid present; ascospores ca. 8 x 2.5-3 mu - - - Myriotrema terebratulum

221A (215) Ascocarps 0.3-0.6 mm wide with more or less split margin; ascospores ca. 15-18 x 5-6 mu, 6-8 celled; stictic acid present - - - Chapsa pseudoschizostoma
221B Ascocarps 0.7-1.1 mm wide with entire margin; ascospores ca. 18-21 x 5-6 mu, 5-6 celled; unidentified P-negative compound present - - - Thelotrema esslingeri

222A (214) Ascocarp pores filled by inner excipulum, hardly visible; ascospores ca. 24 x 8 mu, 5-7 celled; hypoprotocetraric acid present - - - Thelotrema refertum
222B Ascocarp pores without visible inner excipulum, open and showing the disc when wide enough - - - 223

223A Ascocarp warts up to 0.5(-0.6) mm wide - - - 224
223B Ascocarp warts 0.5-1.0 mm wide; protocetraric acid present; ascospores ca. 24-28 x 7-8 mu, 7-8 celled - - - Ocellularia mauritiana

224A Ascocarps 0.3-0.6 mm wide, distinctly raised, with 0.1-0.3 mm wide pore; ascospores ca. 20 x 6 mu, 6 celled; psoromic acid, usually with stictic acid present - - - Ocellularia "gerardii"
224B Ascocarps 0.2-0.3 mm wide, hardly raised, with 0.1 mm wide pore; ascospores ca. 28-35 x 10-12 mu, 10-12 celled; psoromic acid present - - - Myriotrema glaucophaenum

230A (210) Ascocarps opening by a minute pore under 0.1 mm wide, usually completely immersed in the thallus - - - 231
230B Ascocarps with wider opening, with the disc exposed, often raised above the thallus - - - 234

231A Ascospores I-negative, ca. 20-25 x 9-12 mu, 8-10 x 3-4 celled; thallus with filmy cortex; stictic acid present - - - Thelotrema glaucopallens
231B Ascospores I+ bluish; thallus with not filmy cortex; stictic acid absent - - - 232

232A Ascocarps in groups of ca. 5-10 or larger when groups confluent, superficial in the thallus, with disc visible, with dark proper excipulum; ascospores ca. 18 x 9 mu, 6 x 2 celled; lichen substances absent - - - Myriotrema "aggregans"
232B Ascocarps regularly scattered, deeply immersed with the disc not visible in the pore - - - 233

233A Ascospores small, ca. 12-14 x 6-8 mu, 4 x 1-2 celled; norstictic acid present - - - Myriotrema norsticticum
233B Ascospores larger, ca. 18-25 x 8 mu, 6 x 1-2 celled; lichen substances absent - - - Myriotrema "pseudopycnoporellum"

234A Ascospores over 30 mu long; ascocarp pore filled by the inner excipulum; ascospores 8/ascus, I-negative, ca. 35-50 x 12-15 mu, ca. 8-12 x 1-2 celled; lichen substances absent - - - Thelotrema adjectum
234B Ascospores less than 25 mu long - - - 235

235A Ascospores I-negative, with thin septa - - - 236
235B Ascospores I+ bluish, with thickened septa and rounded lumina - - - 238

236A (53) Ascocarps with low, crumbling, occasionally slightly slip-forming thalline margin; lichen substances absent? - - - 237
236B Ascocarps without distinct thalline margin; ascospores ca. 18 x 6 mu, ca. 6 x 1-2 celled; usually psoromic acid present - - - Chapsa kalbii?

237A Ascospores 1/ascus, ca. 55-75 x 18-25 mu, ca. 16-30 x 6-10 celled - - - Chapsa leprocarpa
237B Ascospores 8/ascus, ca. 30-35 x 8-10 mu, 13-16 x 1-2 cells, submuriform - - - Chapsa cinchonarum?

238A Ascocarps immersed in the thallus, with ca. 0.1-0.2 mm wide pores; thallus fissured; ascospores ca. 20 x 12 mu, 6 x 3 celled; psoromic acid present - - - Myriotrema clandestinum
238B Ascocarps sessile or raised in thallus warts; thallus continuous - - - 239

239A Ascocarps immersed in slightly raised warts, with ca. 0.2 mm wide pore; hymenium ca. 250 m; ascospores ca. 60-65 x 25-30 mu, ca. 14 x 5 celled; psoromic acid present - - - Thelotrema cryptotrema
239B Ascocarps sessile on the thallus, with 0.2-2 mm wide disc surrounded by an often swollen, pale thalline margin; hymenium 80-100 mu; ascospores ca. 12-20 x 7-9 mu, 4-8 x 1-2 celled; psoromic acid present or no lichen substance present - - - Stegobolus wrightii