Lichen determination keys - neotropical genera -

Key to (obligately) foliicolous, crustose lichens

primary / fruticose / foliose / squamulose / foliicolous / crustose / lichinaceae
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A worldwide key is offered by Robert Lücking. His website also contains a checklist and good photographs.

1a Thallus with c. 0.1-2 mm long, sterile bristles/hairs---2
1b Thallus with dish-like, stalked isidia; ascocarps absent---Porina ("Phyllophiale")
1c Thallus without such structures, naked or sometimes with more or less hair-like hypophores, tomentose, or with cylindrical isidia---18

2a Ascocarps absent: sterile, hairy plants cannot be identified with certainty; they are arranged artificially under Tricharia melanothrix Fée, with black hairs, and T. leucothrix Fée, with white hairs)
2b Ascocarps present---3

3a Ascocarps immersed, disc level with thallus surface, sometimes surrounded by a raised, rim-like thallus area---4
3b Ascocarps sessile, often constricted at the base---13

4a Perithecia present; hairs on the perithecia---5
4b Apothecia present; hairs mostly on the thallus---6

5a Hairs on perithecia tiny, scattered---Porina
5b Hairs on perithecia coarse, in apical whirl---Trichothelium

6a Hairs white. often over 1 mm long---7
6b Hairs brown to black, short, under 0.2 mm---12

7a Hairs tiny, dense, forming tomentose areas on the thallus and thalloid apothecial margins---Mazosia
7b Hairs larger, often over 1 mm long, bristle-like---8

8a Thallus with cortical layer of quadratic, rectangular or rounded cells, one cell-layer thick---9
8b Thallus without cortical layer or with a cartilaginous cortical layer---11

9a Ascospores transversely septate; epithecial algae absent---Asterothyrium
9b Ascospores muriform; epithecial algae present---10

10a Thallus more or less extended and flat---Gyalectidium
10b Thallus consisting of more or less confluent, c.0.5 mm wide, convex cushions---Bullatina

11a Ascocarps surrounded by a raised thalloid rim---Calenia
11b Ascocarps without raised thalloid rim, with a more or less distinct excipulum---Echinoplaca

12a (6) Ascocarps without black proper margin---Caleniopsis
12b Ascocarps with black proper margin---Aulaxina

13a (3) Excipulum laterally spreading over the thallus, thus apothecia seemingly immarginate---Echinoplaca
13b Excipulum not laterally spreading, apothecia distinctly marginate---14

14a Apothecium disc smooth, without central, sterile part---Tricharia
14b Apothecium disc umbonate, with central, sterile part---Paratricharia

18a (1) Ascocarps present---19
18b Ascocarps absent, but conidangia or goniocystangia present---82

19a Apothecia present, rounded, occasionally with punctiform discs arranged in lines---20
19b Lirellae present, elongate with black labiae---63
19c Perithecia present---70

20a Ascocarps without visible margin---21
20b Ascocarps with clearly differentiated margin---30

21a Fruitbodies white, with asci scattered in loose, medulla-like tissue---22
21b Fruitbodies coloured or white, compact, with asci in differentiated, usually gelatinous hymenium---24

22a Asci in poorly delimited thallus warts---23
22b Asci in non-gelatinous ascocarps well delimited from the thallus---Amazonomyces

23a Ascospores muriform---Cryptothecia
23b Ascospores transversely septate only---Stirtonia

24a Asci with I+ blue tholi; ascospores transversely septate---25
24b Asci with I-negative tholi; ascospores transversely septate or muriform---26

25a Paraphyses simple and straight; hymenium gelatinous, I+ blue; ascocarps completely flat, level with thallus---Byssolecania
25b Paraphyses simple and straight; hymenium gelatinous, I+ blue; ascocarps convex, sessile---Loflammiopsis
25c Paraphyses branched and anastomosing; hymenium not gelatinous, I-negative---Vezdaea

26a Hymenium I+ red or blue---27
26b Hymenium I-negative---31

27a Ascospores muriform---Arthothelium
27b Ascospores transversely septate---28

28a Ascocarps seemingly punctiform and arranged in lines---Enterographa
28b Ascocarps disciform, more or less deeply lobate---29

29a Conidia filiform, over 50 µm long; pycnidia elongate with lateral pore---Eremothecella
29b Conidia bacillar, under 20 µm long; pycnidia rounded with apical pore---Arthonia

30a (20) Apothecia immersed in the thallus, disc level with thallus surface, sometimes surrounded by a raised thallus rim---31
30b Apothecia adnate to sessile, often constricted at the base; disc above thallus surface---35

31a (26, 30) Thallus with cortical layer of quadratic, rectangular or rounded cells, one cell-layer thick---32
31b Thallus without cortical layer, or with a cortical layer of conglutinated, unmodified hyphae---33

32a Ascospores transversely septate; epithecial algae absent---Asterothyrium
32b Ascospores muriform; epithecial algae present---Gyalectidium

33a Paraphyses simple; with laciniate, erect or recurved, thalline margin; hyphophores absent---Chroodiscus
33b Paraphyses branched and anastomosing; without thalline margin; hyphophores present---34

34a Ascospores bicellular; hyphophores stalked---Echinoplaca
34b Ascospores at least 3-septate; hyphophores without stalk, consisting of a sessile, gelatinous ball---Actinoplaca

35a (30) Hymenium I+ blue, at least after pretreatment with diluted KOH solution, and at least near the asci; asci I+ blue, usually in the tholus, at least along the outside---36
35b Hymenium I+ reddish; asci I-negative---Mazosia
35c Hymenium and asci I-negative or very pale blue---55

36a Ascospores simple---37
36b Ascospores transversely septate only---38
36c Ascospores muriform---46

37a Thallus smooth, containing green algae; apothecia with pronounced margin---"Lecidea gr. piperis"
37b Thallus granular, containing blue-green algae; apothecia soon convex and with indistinct margin---Biatora s.l.

38a Excipulum formed externally by loose, felty hyphae---Byssoloma
38b Excipulum compact, also externally---39

39a Asci with an I+ blue tubular structure in the apex---40
39b Asci without tubular structure, with or without an I+ blue axial mass---41

40a Apothecia usually over 0.5 mm wide, flat; I-positive tubular structure in ascus apex distinctly stained over its whole length; excipulum usually filled with crystals---Badimia
40b Apothecia mostly under 0.5 mm side, soon convex; I-positive tubular structure in ascus apex most distinctly stained in its basal part; excipulum not filled with crystals---Fellhanera

41a Campylidia absent; asci with conical or rounded, I+ pale blue axial mass---42
41b Campylidia (usually) present; asci without I+ pale blue axial mass---43

42a Asci with conical axial mass; excipulum prosoplectenchymatic---Bacidia
42b Asci with rounded axial mass; excipulum paraplectenchymatic---Bacidina

43a Hypothecium purplish; apothecia black, sometimes with white pruina---Tapellaria
43b Hypothecium usually not purplish; apothecia variously coloured---44

44a Ascospores 3-septate, fusiform---45
44b Ascospores 7-septate, bacillar; campylidia as in Calopadia---"Tapellariopsis"
44c Ascospores many-septate, over 10-septate, acicular; no campylidia---Bapalmuia

45a Campylidia producing flask-shaped, c 20 µm long conidia---Barubria
45b Campylidia producing ovoid, c. 10 µm long conidia---Loflammia

46a (36) Margin of apothecium with long, stiff hairs---Lasioloma
46b Margin of apothecium without such hairs---47

47a Epithecial algae present---Sporopodium
47b Epithecial algae absent---48

48a Apothecia black, sometimes with white pruina, with flat disc; hypothecium purplish---Tapellaria
48b Apothecia not black, variously coloured, with flat or convex disc; hypothecium not purplish---49

49a Apothecia yellowish, soon convex---Logilvia
49b Apothecia reddish to dark brown or grey-brown, with flat disc---50

50a Apothecia dark brown to grey-brown, with flat disc---Calopadia
50b Apothecia red to carmine, with flat disc---Loflammia

55a (35) Apothecia elongate to angular or round, not constricted at base, margin formed by a dark tissue which initially covers the disc---Aulaxina
55b Apothecia round to slightly irregular, margin not formed by a dark tissue which initially covers the disc---56

56a Apothecia proliferating on their margins; mainly on leaf margins---Polystroma
56b Apothecia not proliferating on their margins---57

57a Paraphyses simple, straight---58
57b Paraphyses branched and anastomosing---61

58a Ascospores bicellular---59
58b Ascospores pluricellular---Gyalidea

59a Apothecia yellow to orange; ascospores bicellular in cylindrical asci (NB: for species determination it is important to study the pyncidia, which are often found on separate plants)---Dimerella
59b Apothecia grey or brown to blackish---60

60a Ascospores single in the asci---Psorotheciopsis
60b Ascospores 8 in each ascus---Linhartia

61a Excipulum thinly spreading laterally over the thallus---Echinoplaca
61b Excipulum not spreading, forming a prominent margin---62

62a Without bristle-like hyphophores---Gyalideopsis
62b With bristle-like hyphophores---Actinoplaca

63a (19) Hymenium I-negative; ascospores sometimes I+ blue-violet; paraphyses unbranched or slightly branched apically (Graphidales, occasionally on leaves)---see key to crustose lichens, #257
63b Hymenium I+ blue and/or red; ascospores I-negative; paraphyses branched and anastomosing (Opegraphales, frequent on leaves)---64

64a Asci with thick apical dome---Arthonia
64b Asci with thin apical dome---65

65a Ascocarps immersed in thallus, without black margins---Enterographa
65b Ascocarps more or less raised, with black margins---66

66a Ascocarps with constricted base; ascospore cells not swollen---Opegrapha
66b Ascocarps with gradually ascending base; ascospores with swollen (sub-) median cell---Mazosia

70a (19) Thallus subcuticular, very glossy---Strigula
70b Thallus epicuticular, forming a usually dull sheet over the cuticula of the leaf---71

71a Perithecia with warts, bristles or a disc-like expansion around the pore; ascospores transversely septate or muriform---72
71b Perithecia simple---74

72a Perithecia whitish, with a disc-like extension around the pore or with more scattered scales---Aspidothelium
72b Perithecia reddish or black, rarely whitish, with bristle-like extensions, usually in a whirl around the pore---73

73a Asci bitunicate; ascospores 14-17 x 3-4 µm, transversely 3-septate---Lyromma
73b Asci thinwalled; ascospores usually over 18 µm long, variously septate---Trichothelium

74a Ascospores pale grey-brown, transversely 3-septate---Microtheliopsis
74b Ascospores colourless, transversely septate or muriform---75

75a Paraphyses absent or desintegrating early; algae chlorococcoid---Macentina
75a Paraphyses absent or desintegrating early; algae Trentepohlia-like---Pocsia
75b Paraphyses (s.l.) persistent---76

76a Ascospores one-septate---77
76b Ascospores transversely many-septate---78
75c Ascospores muriform---79

77a Ascospores under 30 µm long---Anisomeridium
77b Ascospores over 50 µm long---Musaespora

78a Perithecia solitary---Porina
78b Perithecia grouped in raised thallus parts---Flavobathelium

79a Perithecia with outer wall containing dark-brown pulverous masses, often irregularly shaped---Phyllobathelium
79b Perithecia with outer wall without such masses, regular---80

80a Ascospores lumbricoid, with few longitudinal septa---Phylloblastia
80b Ascospores oval, with numerous longitudinal septa---Thelenella

82a (18) Conidangia present---83
82b Goniocystangia present, black-rimmed, resembling ascocarps, but producing goniocysts, present---Opegrapha gr. lambinoni

83a Conidangia strongly exserted, ear- or brush-like, variously coloured---84
83b Conidangia immersed or only slightly exerted conidangia, black or concolorous with thallus---92

84a Campylidia (ear-like structures) present (artificially arranged in the genus Pyrenotrichum)---85
84b Hyphophores or other brush-like conidia-producing structures present---91

85a Conidia ovoid to pyriform, simple or uniseptate---86
85b Conidia more elongate, bacillar or branched, simple or variously septate---88

86a Conidia uniseptate, with unequal cells; usually found with ascocarps---Byssoloma
86b Conidia simple; often found without ascocarps---87

87a Campylidia short, on top of a thalloid cylinder; algae between the conidiophores---Sporopodium
87b Campylidia not on thalloid cylinder; no algae between the conidiophores (Loflammia and Logilvia have similar campylidia, but are unlikely to be found without ascocarps)---Musaespora

88a Conidia flask-shaped, non-septate---Barubria
88b Conidia filiform, septate, sometimes branched---89

89a Conidia branched, somewhat star-shaped---Lasioloma
89b Conidia not branched---90

90a Conidia cylindrical, to c. 40 µm long, without appendages---Arthonia
90b Conidia cylindrical, c. 100 µm long, with appendages (short branchlets)---Badimia
90c Conidia tapering, c. 50 µm long, without appendages (genera can be separated only by ascocarp characters)---Calopadia/Tapellaria

91a (84) True hyphophores present, bristle-like or flattened, producing conidia in free-hanging gelatinous balls---Echinoplaca
91b Hyphophores absent, but bristle-like conidangia present; conidia not produced in free-hanging gelatinous balls, but inside the conidangia---92

92a (83) Conidangia brown to black, star-like branched; on leaf upper surface---Lyromma
92b Conidangia pale brown, simple; on leaf margin---Bacidina

93a Conidangia black---94
93b Conidangia pale, inconspicuous---Dimerella

94a Conidia simple---Anisomeridium
94b Conidia septate---95

95a Conidangia separate---Strigula
95b Conidangia in groups of c. 10-30 in elevated thallus areas---Phyllobathelium

primary / fruticose / foliose / squamulose / foliicolous / crustose / lichinaceae
about / literature / glossary / list

(c) Botanischer Garten und Botanisches Museum Berlin-Dahlem, Freie Universität Berlin
page editor: Harrie Sipman, last update: 20 December 2000, imprint
http://www.bgbm.org/sipman/keys/neokeyF.htm