Lime Loving Lichens
This key was first compiled for the 1997 Tuckerman Workshops. Tuckerman Workshop 5 took place in the alvar region of New York. The key was substantially revised based on the alvar collections and observations for Tuckerman Workshop 6 in Missouri. A further major revision resulted from collections made in the extensive dolomitic region in the southern part of Missouri. The author is grateful for the many corrections and improvements contributed by the workshop participants. Subsequently, as stray bits of pertinent information, additional records and corrections have come to hand, additional changes have been made. Further modifications are anticipated and, indeed, it is hoped that users will send information regarding omitted taxa, errors and range extensions (much is still based on literature and therefore highly suspect). The web version will be updated as need (and opportunity) arises. 14 August 1999.
WARNING. This is not a general lichen key. It treats only those species occurring on lime rich rock or soil in the region covered by the 'Lichen Flora of Eastern North America'. Any other use may be hazardous to your temper and mental health for which the author accepts no liability.
1. Thallus fruticose, foliose or squamulose (tiny blackish filamentous, subfruticose, subfoliose or areolate Lichinaceae/Placynthiaceae are keyed with crustose species) ... 2
1. Thallus crustose ... 71
2. Thallus foliose, bright yellow to deep orange ... 3
2. Thallus some shade of gray, brown or black ... 10
3. Thallus KOH + purple; on rock ... 4
3. Thallus ± unchanged by KOH; lobes bright yellow, narrow, 0.1-0.5 mm wide, sorediate; sorediate lobes often ± fan-shaped, slightly raised; only rarely with apothecia; mainly on HCl- rock or on bark, only rarely on calcareous rock ... Candelaria concolor (Dickson) Stein
4. Lobes moderately adherent to rock, with a lower cortex (Xanthoria) ... 5
4. Lobes tightly adherent to rock, without a lower cortex See Caloplaca
5. Thallus sorediate or isidiate-sorediate ... 6
5. Thallus not sorediate or isidiate ... 9
6. Thallus with terminal or marginal soralia ... 7
6. Thallus with coarse isidia occasionally breaking open and forming granular soredia ... Xanthoria sorediata (Vainio) Poelt
7. Lobes relatively broad, ca. 0.8-1.4 mm wide ... 8
7. Lobes narrow, ca. 0.3-0.5 mm wide; pycnidia conspicuous, orange to red; soredia on apices and lower side of lobes; known from Missouri on dolomite ... Xanthoria fulva (Hoffm.) Poelt & Petutschnig
8. Soralia forming in slits surrounded by a cortical margin ("birds nest" soralia); not known to me from limestone ... Xanthoria fallax (Arnold) Arnold
8. Soralia marginal, submarginal or rarely laminal; soredia coarse; Missouri from dolomite area on HCl- inclusion ... Xanthoria ulophyllodes Räsänen
9.(5) Lobes convex, narrow, to 1 mm; tips convex, not thin and fan-shaped; on dolomites and limestones, coastal and inland, especially near water ... Xanthoria elegans (Link) Th. Fr.
9. Lobes flattened, broader to 5 mm; tips thin and fan-shaped; occasional? on HCl+ rock, normally on trees or HCl- rock; strictly coastal? ... Xanthoria parietina (L.) Th. Fr.
10.(2) Thallus foliose or umbilicate( ± fruticose in Speerschneidera) ... 11
10. Thallus squamulose, or with squamulose primary thallus and fruticose secondary thallus (Cladonia), mostly on calcareous soil or primary thallus lacking (Cladina) ... 47
11. Photobiont green; thallus gray or brown, greener when wet ... 12
11. Photobiont cyanobacterial; thallus bluish to blackish (brownish in Peltigera), blackish when wet ... 25
12. Thallus umbilicate; ascomata immersed, flask-shaped, lacking paraphyses; hymenial gel I+ blue-green to orangish; ascospores colorless, undivided (Dermatocarpon)... 13
12. Thallus not umbilicate ... 14
13. On flat dolomite rocks (surrounded by grass, apparently not on the pavements?) in alvar; thallus dark gray and appearing pruinose, mainly in central parts; outer parts mostly very dark brown, large and clearly umbilicate to small, crowded lobes where point of attachment is hard to discern; underside light brown in center, very dark brown and wrinkled toward margins; medulla thick and loose; lower cortex ± thin; thus far known only from New York ... Dermatocarpon sp.
13. Usually on vertical faces in humid situations; thallus tan to light brown, if appearing pruinose, then whitish, mostly ± large and umbilicate; underside variable, tan to blackish, ± wrinkled or not; medulla ± thin, compact; lower cortex thicker; widespread ... Dermatocarpon miniatum (L.) Mann (North American material referable to D, americanum Vainio? Most of the material named D. miniatum var. complicatum seems to be D. intestiniforme and occurs on non-calcareous rock. Material with multiple points of attachment on calcareous rock needs to be confirmed. The situation is more complex in Missouri and has yet to be dealt with.)
14. Thallus foliose, adnate to rock or in mosses over rock; ascospores brown, 2-celled ... 15
14. Thallus foliose/fruticose, mostly free from rock; lobes narrow, subcylindrical, dichotomously branched, with cartilaginous texture and hyphae running parallel with the long axis, KOH- ; apothecia with thalline margin; asci Lecanora-type; ascospores colorless, 2-celled; on shaded dolomite, from Missouri southwestward to Mexico ... Speerschneidera euploca (Tuck.) Trevisan
15. Apothecia, if present, sessile; lobes narrow, elongated; sorediate ... 16
15. Apothecia sunken in thallus; asci 4-spored; ascospores large, over 30 µm long; lobes broad, rounded, not sorediate, with poorly developed lower cortex; among mosses over calcareous rock or soil ... Solorina saccata (L.) Ach.
16. Thallus KOH+ yellow (Physcia) ... 17
16. Thallus KOH- ... 20
17. Medulla KOH+ yellow ... 18
17. Medulla KOH-; lobes narrow, to 0.2-1 mm across, not white spotted; soralia marginal, often labriform or occasionally laminal; on rock but occurrence on calcareous rock needs confirmation ... Physcia dubia (Hoffm.) Lettau
18. Thallus smaller, ca. 0.5 mm, white spotted or not; zeorin present or absent ... 19
18. Thallus usually robust, to 1 mm across, strongly white spotted; soralia large, variable, laminal or on short lobes capitate or labriform; zeorin present ... Physcia caesia (Hoffm.) Fürnr.
19. Soralia laminal, orbicular; lobes not or only weakly white spotted; zeorin absent; mostly corticolous but rather commonly saxicolous in Missouri ... Physcia americana Merr.
19. Soralia marginal, granular; lobes tend to become erect; usually white spotted; zeorin present; mostly corticolous, presence on calcareous rock needs to be confirmed ... Physcia millegrana Degel.
20.(16) Lower cortex dark (often pale at tips and margins) ... 21
20. Lower cortex entirely pale, fibrous; soralia terminal and marginal, ± labriform, occasionally laminal; soredia coarse ... Physciella chloantha (Ach.) Essl.
21. Rhizines not squarrose (Phaeophyscia) ... 22
21. Rhizines squarrose; lobes broad, to 3 mm across, often heavily and coarsely pruinose; soralia marginal with coarse soredia; mostly corticolous ... Physconia detersa (Nyl.) Poelt (Physconia kurokawae with medulla KC+ pink (gyrophoric acid) and P. perisidiosa with shorter lobes, labriform soralia and lacking cortex at tips on underside might also occur on calcareous rock, although I have yet to confirm this.)
22. Medulla white ... 23
22. Medulla orange-red; soralia terminal and marginal; soredia granular; mostly corticolous, occurrence on calcareous rock requires confirmation ... Phaeophyscia rubropulchra Degel. (Phaeophyscia endococcinea without soredia is also possible but as yet unverified.)
23. Tips of lobes without small, erect, colorless hairs ... 24
23. Tips of lobes with small, erect, colorless hairs; soralia marginal; on calcareous sandstone, Wisconsin ... Phaeophyscia cernohorskyi (Nádv.) Essl.
24. Soredia pale, granular; terminal and marginal; lobes mostly more than 0.5 mm across; mostly on HCl- rock or trees ... Phaeophyscia adiastola (Essl.) Essl.
24. Soredia dark, isidioid (or with dark isidia), mostly marginal; lobes narrow, mostly less than 0.5 mm across; mostly on HCl- rock? ... Phaeophyscia sciastra (Ach.) Moberg
25.(11) Thallus with distinct photobiont and medullary layers; mostly on soil (Peltigera) ... 26 (More species may occur as most seem somewhat minerotrophic. Only the ones which seem to me most calciphilous are included here.)
25. Thallus not divided into distinct layers ... 32
26. Upperside tomentose ... 27
26. Upperside not tomentose; apothecia short stalked, blackish; lobes usually small, to 1.5 cm, shiny; veins becoming dark, reticulate, often thick ... Peltigera neckeri Müll. Arg.
27. Thallus isidiate or phyllidiate ... 28
27. Thallus not isidiate or phyllidiate ... 30
28. With "true" isidia, laminal, granular, cylindrical or peltate ... 29
28. With phyllidia (squamules/lobules), marginal or along wounds or cracks in the cortex; underside veined, pale (if black, ± smooth = P. elisabethae which does not seem to be calciphilous) ... Peltigera praetextata (Sommerf.) Zopf
29. Isidia peltate or ± squamulose; thallus small, ca. 5-7 mm across ... Peltigera lepidophora (Vainio) Bitter
29. Isidia granular to ± cylindrical, occasionally branched, rarely ± squamulose; thallus larger ... Peltigera evansiana Gyelnik
30.(28) Rhizines and veins soon dark ... 31
30. Rhizines and veins remaining pale; marginal rhizines slender, mostly unbranched ... Peltigera ponojensis Gyelnik
31. Rhizines richly branched, confluent; lobes small to medium, 5-10 mm across, often strongly tomentose, with raised, crisped margins ... Peltigera rufescens (Weis) Humb.
31. Rhizines pale and unbranched at margins; lobes larger, 10-15 mm across, moderately tomentose, with ± erect, even margins; usually developing phyllidia along margins or along cracks in the thallus ... Peltigera praetextata (Sommerf.) Zopf
32.(25) Thallus generally bluish (brown in L. dactylinum), with a cortex of a single layer of cells (Leptogium. Only the most calciphilous are included. Other species such as L. cyanescens and L. teretiusculum might occur.) ... 33
32. Thallus generally blackish, lacking a cortex (Collema) ... 35 (Looking dead, with immersed apothecia and non-septate ascospores see Lempholemma)
33. Lobes not fringed; apothecia common ... 34
33. Lobes ± longitudinally wrinkled, lobe tips very finely divided, appearing as a fringe of long isidia; apothecia rare ... Leptogium lichenoides (L.) Zahlbr.
34. Lobes not wrinkled, usually isidiate, 1-4 mm across ... Leptogium dactylinum Tuck. (Alvar collection from soil in an ephemerally wet depression. Collema sp. growing on moss tufts on rock is very similar and probably best separated by thallus x-section or by 4-celled ascospores in Collema vs. submuriform in L. dactylinum.)
34. Lobes longitudinally wrinkled, not isidiate, narrow, 0.5-1 mm across, canaliculate below ... Leptogium apalachense Nyl.
35.(32) Thallus isidiate 36
35. Thallus not isidiate 39
36. Thallus ± flat with broad, rounded lobes; isidia globose, ± evenly distributed; more often on bark and non-calcareous rock ... Collema subflaccidum Degel.
36. Thallus lobes narrower, irregular and often convoluted ... 37
37. Growing on moss colonies on rock; thallus dark brown, ± thin; isidia variable, sometimes globose but at least some squamiform (lobulate); apothecia often present, sessile; ascospores 4-celled ... Collema sp. (I do not seem to come to a name in Degelius' works, probably stupidity. It may prove to be an alvar ecotype of C. undulatum. It is very similar in aspect to Lempholemma (immersed apothecia, simple ascospores) and Leptogium dactylinum (submuriform ascospores, corticate thallus).)
37. Growing on rock; thallus thicker; isidia all ± globose ... 38 (totally reliable separation of following 2 species depends on ascospores)
38. Thallus blackish, with concave undulate lobes, 2-4 mm across; ascospores 4-celled ... Collema undulatum Flotow var. granulosum Degel.
38. Thallus dark olive-green, ± thin, ± broader, 2-5 mm across; ascospores muriform ... Collema fuscovirens (With.) Laundon
39.(35) Ascospores 2-celled ... 40
39. Ascospores 4-celled or submuriform-muriform ... 41
40. Thallus of distinct, elongate lobes; tips not swollen ... Collema texanum Tuck.
40. Thallus with short, crowded indistinct, swollen lobes ... Collema coccophorum Tuck.
41. Ascospores 4-celled ... 42
41. Ascospores submuriform-muriform ... 44
42. Lobe tips not swollen or raised on edge ... 43
42. Lobe tips ± swollen (tenax type), ± raised on edge; exciple below hypothecium of broadly rectangular cells (subparaplectenchymatous) ... Collema polycarpon Hoffm.
43. Exciple below hypothecium cellular (paraplectenchymatous); ascospores 6.5-9 µm ... Collema undulatum Flotow
43. Exciple below hypothecium of broadly rectangular cells (subparaplectenchymatous); ascospores broader, usually 13-15 µm ... Collema crispum (Hudson) F. H. Wigg.
44. Lobe tips ± swollen (tenax type) ... 45
44. Lobe tips not swollen ... 46
45. Apothecial margin ± even; ascospores 8.5-10.5 µm broad ... Collema tenax (Sw.) Ach.
45. Apothecial margin coarsely crenate; ascospores broader, ca. 13 µm ... Collema bachmanianum (Fink) Degel.
46. Asci 8-spored; on rock; apothecia initially completely immersed; thallus often subfruticose ... Collema pustulatum Ach.
46. Asci 4-spored; on soil; apothecia immersed or sessile; thallus forming thin crust over soil ... Collema limosum (Ach.) Ach.
47(10). Squamules larger, not closely appressed to rock or lacking (Cladina) ... 48
47. Squamules/areoles small, closely appressed to rock, usually tan or brown; ascospores 2/ascus, colorless, muriform; hymenial algae present ... Endocarpon pusillum Hedwig
48. Photobiont cyanobacterial Scytonema, (if Nostoc, try Collema or Lempholemma, if coccoid with colored sheath, try Lichinaceae) (Heppia, modified from Henssen, 1994) ... 49
48. Photobiont a green alga ... 51
49. Thallus squamulose to peltate with a continuous lower or upper cortex; hymenium blue or reddish in iodine ... 50
49. Thallus granulose or squamulose, blackish, gelatinous, not layered or marginally with a rudimentary lower cortex; ascus wall staining intensely blue in iodine ... Heppia lutosa (Ach.) Nyl.
50. Thallus with lower cortex formed by periclinally arranged hyphae; hymenium reddish in iodine ... Heppia adglutinata (Kremp.) Massal.
50. Thallus with broad, pseudoparenchymatous upper cortex; hymenium blue in iodine, reddish above ascus tips ... Heppia conchiloba Zahlbr.
51.(48) Squamules with white underside readily visible, mostly attached at one end, raised, often overlapping shingle fashion or primary thallus lacking; ascomata usually borne on fruticose podetia (Cladina/Cladonia) ... 52
51. Squamules without white underside or underside not readily visible, usually appressed to substrate; ascomata sessile or immersed ... 63
Before visiting the New York alvars I would have said that Cladina was not found in lime rich situations. Ahti in his 1961 revision also states "Calcareous ground is avoided by most species ...". This is obviously not the case in alvars. I can think of a couple possible explanations (surely there are others). One is that there are ecological races adapted to lime. The other is that the reindeer lichens are similar to Sphagnum in their ability to create their own environment. Perhaps a propagule establishes on some organic matter and the decomposition of the basal parts of the podetia neutralize the lime allowing for the gradual expansion of the colony. I suggest that it might be revealing to make pH readings in various parts of a colony and its immediate surroundings. As a consequence I have added several species of Cladina to the key as "lime tolerant".
52. Podetia intricately branched, lacking a cortex, not squamulose; primary squamules lacking (Cladina, treatment is cursory as keys available many places and only those actually collected at alvar sites thus far are included.) ... 53
52. Podetia not intricately branched or if so, then corticate, often squamulose; primary squamules often conspicuous (Cladonia) ... 55
53. Thallus yellowish (usnic acid) ... 54
53. Thallus gray, containing atranorin and fumarprotocetraric acid ... Cladina rangiferina (L.) Nyl.
54. Thallus with branches in 3's and 4's; branching ± loose; surface compact; fumarprotocetraric acid present ... Cladina arbuscula (Wallr.) Hale & Culb.
54. Thallus with branches in 4's in tight whorls; surface distinctly fuzzy; lacking fumarprotocetraric acid ... Cladina stellaris (Opiz) Brodo
55(52). Podetia cup-forming; containing fumarprotocetraric acid ... 56
55. Podetia not cup-forming, pointed or ending in apothecia or podetia lacking ... 59
56. Podetia short, stout, with ± regular cups (C. pyxidata group) ... 57
56. Podetia tall, relatively slender, with highly irregular cups with perforate or torn membrane, with ± continuous cortex; only fumarprotocetraric acid (in calcareous areas often intergrades with C. furcata) ... Cladonia multiformis G. K. Merr.
57. Basal squamules thinner, ± erect, mostly separate, greenish to brownish; cups smooth to warty-areolate or partly decorticate ... 58
57. Basal squamules 1-2 mm thick, fused into a flattened, almost foliose rosette with ± lobed margin, shiny, becoming brown; cups remaining corticate outside, warty-areolate inside; ±atranorin (The New York alvar collection has atranorin) ... Cladonia pocillum (Ach.) Grognot
58. KOH+ yellow, (atranorin); cups distinctly gray, often with small squamules; a strong calciphile ... Cladonia magyarica Vainio
58. KOH-, UV- (lacking atranorin); cups becoming brownish; not calciphilous but present in alvars on decaying wood or patches of non-calcareous soil (UV+ = C. grayi) ... Cladonia pyxidata (L.) Hoffm.
59. Squamules usually ± small; podetia usually present, much branched and corticate or cylindrical, pointed or with apothecia, sorediate or with dispersed areoles ... 60
59(55). Squamules usually ± large; podetia usually absent (if present in C. dahliana ± inflated, corticate, with many small apothecia) ... 62
60. Squamules PD+ yellow, KOH+ yellow or red (norstictic or psoromic acids) ... 61
60. Squamules PD-, KOH- (perlatolic acid) ... Cladonia decorticata (Flörke) Sprengel
61. Atranorin absent; squamules KOH+ red (norstictic acid); probably not strongly calciphilous but collected in New York alavar ... Cladonia polycarpoides Nyl.
61. Atranorin present; KOH- or KOH+ red (psoromic acid [var. acuminata] or norstictic acid [var. norrlinii Lynge]) ... Cladonia acuminata (Ach.) Norrlin
62(59). Squamules PD+ yellow (psoromic acid plus atranorin) ... Cladonia dahliana Kristinsson (sometimes included in C. symphycarpa (Flörke) Fr. [norstictic acid] which might possibly occur in our region)
62. Squamules PD+ orange-red (fumarprotocetraric acid plus atranorin) ... Cladonia apodocarpa Robbins
63. Ascomata immersed, flask-shaped; all tissues lacking oxalate crystals; lower cortex black; on soil ... 64
63. Ascomata sessile, disk-shaped; hypothecium, cortex and/or medulla mostly with oxalate crystals; lower cortex absent or poorly developed, pale ... 66
64. Squamules brown, usually shiny, not pruinose 2-5 mm across; pycnidia laminal; pycnospores 3-5 µm long; ascospores 12-16 x 5.5-7 µm ... 65
64. Squamules gray, pruinose, 0.5-3 mm across ... Catapyrenium cinereum (Pers.) Körber
65. Thallus attached to substrate only by weft of hyphae ... Placidium squamulosum (Ach.) Breuss
65. Thallus attached to substrate by rhizines in addition to hyphal weft ... Placidium lacinulatum (Ach.) Breuss (Breuss (1990) suggests that it may be necessary to wet the material to separate rhizines from the soil as they are fragile when dry and remain with the soil.)
66(63). Ascospores not septate, colorless ... 67
66. Ascospores 1-septate, colorless, fusiform, 14-25 x 2.5-5 µm; squamules ca. 3 mm across, usually strongly bluish or whitish pruinose, usually ± swollen ... Toninia sedifolia (Scop.) Timdal
67. Apothecial pigment KOH+ reddish; oxalate crystals present, at least in hypothecium (Psora) ... 68
67. Apothecial pigment KOH-; oxalate crystals absent; squamules to 5 mm, brown; apothecia dark brown; ascospores not septate, 9-11 x 6-8 µm [the ascus is of the Porpidia-type and the general aspect of the apothecial x-section strongly suggests relationship with Clauzadea.] ... "Psora" lurida (Ach.) DC.
68. Apothecia laminal to submarginal; squamules not reddish ... 69
68. Apothecia marginal; squamules ± bright reddish, isodiametric with ± upturned margin; on soil ... Psora decipiens (Hedwig) Hoffm.
69. Norstictic acid lacking; on rock ... 70
69. Norstictic acid present; squamules ± isodiametric, brown, pruinose or not; on soil ... Psora russellii (Tuck.) A. Schneider
70. Apothecia reddish brown; squamules with white pruinose margin; medulla with oxalate crystals ... Psora pseudorussellii Timdal
70. Apothecia dark brown to black; squamules brown, pruinose or not; medulla without oxalate crystals ... Psora globifera (Ach.) Massal.
71(1). Photobiont a green alga 72
71. Photobiont a cyanobacterium (Lichinaceae-Placynthiaceae) ... 169
72. Thallus or apothecia not yellow or orange ... 73
72. Thallus or apothecia some shade of yellow or orange ... 158
73. Thallus ecorticate, a thin to thick layer soredium-like granules on a thin to thick hypothallus; ascomata unknown; identification largely chemical (Lepraria) ... 74
73. Thallus not as above; ascomata known (not always present) ... 75
74. Thallus whitish or grayish, thick, with a brownish hypothallus, PD+ orange (atranorin, zeorin, sticitc acid agg., pannaric acid derivative?, probably should be transferred to Leproloma) ... Lepraria lobificans Nyl.
74. Thallus a dirty olive-green, thin; hypothallus not conspicuous (unknown terpene) ... Botryolepraria lesdainiii (Hue) Canals et al.
75. Ascomata disk-shaped (apothecial) or elongated (lirelline) ... 76
75. Ascomata flask-shaped (perithecial) ... 129
76. Asci with 8 or fewer spores ... 77
76. Asci with many tiny spores ... 115
77. Ascospores colorless, not septate to muriform ... 78
77. Ascospores brown, 2-celled to submuriform ... 112
78. Ascospores not septate ... 79
78. Ascospores septate ... 97
79. Apothecia with thalline margin or immersed in thallus and margin not evident ... 80
79. Apothecia with only proper margin, sessile (if margin excluded with age, then visible in section) ... 88
80. Apothecia sessile with a thalline margin (Lecanora) ... 81
80. Apothecia immersed in thallus or in a coarse pertusarioid wart ... 85
81. Thallus conspicuous, effigurate-laciniate, usually rosette-forming or smaller and areolate but still conspicuous due to white color ... 82
81. Thallus not visible or only scattered areoles; apothecia small, 0.2-1 mm, pruinose ... 84
82. Thallus larger, effigurate-laciniate ... 83
82. Thallus white, pruinose, of small areoles, to ca. 0.7 mm diam., initially solitary but becoming aggregated and forming weakly rosulate patches with some areoles ± placodioid; apothecia ± immersed with rather thick, weakly crenulate margin; disk yellow brown; ascospores not found; no substances; Presque Isle County, Michigan ... Lecanora albescens (Hoffm.) Branth & Rostrup
83. Thallus densely white pruinose; cortex basically a single layer, grayish in section due to small oxalate crystals, not forming conical bundles which protrude downward into the algal layer ... Lecanora valesiaca Müll. Arg.
83. Thallus densely pruinose at tips, less so inward; cortex 2-layered, the upper filled with brownish crystals (usnic acid?), the lower clear, without crystals, forming conical bundles which project downward into the algal layer; mostly on non-calcareous rock, but apparently occasional on limestone ... Lecanora muralis (Schreber) Rabenh.
84. Apothecial margins ± even, usually pruinose; disk light to medium brown, lightly pruinose or epruinose (several chemotypes, 1. no substances, 2. pannarin, 3. xanthone) ... Lecanora dispersa (L.) Sommerf. agg.
84. Apothecial margins deeply crenate, pruinose; disk dark brown, pruinose; no substances ... Lecanora crenulata Hook.
85(80). Hypothecium colorless ... 86
85. Hypothecium and lower hymenium filled with orange crystals (KOH+ purple); thallus epilithic, continuous, white, mat; apothecia immersed, emarginate, brown-black, 0.5-1.0 mm diam, thin, ca. 150-200 µm; upper hymenium gray brown, N+ weakly purplish; hymenium 80-90 µm thick; ascospores 7-9 x 4-5 µm; Kentucky ... Protoblastenia sp.
86. Apothecia coarse; disk dark; ascospores large, ± ellipsoid to globose, 18-50 x 14-40 µm ... 87
86. Apothecia immersed, thin, flush with thallus, pallid; paraphyses moniliform at tips; ascospores smaller, 13-22 x 5-12 µm; on very humid rock near water ... Hymenelia epulotica (Ach.) Lutzoni
87. Apothecia 1-few/areole, initially immersed but later with coarse raised margin; paraphyses with moniliform tips; on rock ... Aspicilia contorta (Hoffm.) Kremp.
87. Apothecia single in a coarse pertusarioid wart; paraphyses not moniliform; on bryophytes or soil ... Megaspora verrucosa (Ach.) Hafellner & V. Wirth
88(79). Hypothecium or exciple brown; ascus Porpidia type ... 89
88. Hypothecium and interior of exciple colorless or suffused with pink or purple; outer exciple and epithecium green; thallus not visible to areolate, with zeorin plus atranorin or zeorin plus lichexanthone; ascus Lecanora type; ascospores 10-18 x 5-10 µm; also on HCl- rock ... Lecidella stigmatea (Ach.) Hertel & Leuckert
89. Hypothecium brown ... 90
89. Hypothecium ± colorless; exciple, especially outer part, orange brown; ascospores halonate, 16-20 x 8-10 µm; thallus white, endolithic; apothecia forming shallow pits in rock; Missouri ... Clauzadea metzleri (Körber) D. Hawksw.
90. Hypothecium red- or orange-brown, often redder in KOH ... 91
90. Hypothecium dark brown, KOH- ... 93
91. Upper hymenium and exciple greenish; ascospores not halonate ... 92
91. Epithecium and outer exciple orange-brown; ascospores halonate, 8-12 x 4-6 µm ... Clauzadea monticola (Schaerer) Hafellner & Bellem.
92. Thallus endolithic; apothecia shiny; ascospores ± globose, 9-11 µm or ovoid, c. 8 x 12 µm; ascus Porpidia type; paraphyses very coarse; Missouri ... "Pachyphysis ozarkana"
92. Thallus ± dispersed, ± effigurate areoles; apothecia pruinose; ascospores 12-13 x 4-5 µm; ascus with I- tholus; Michigan ... "Lecidea" sp.
93(90). Growing over bryophytes; exciple and/or hypothecium with dark granules, KOH+ blue-green (removed from Mycobilimbia because of Porpidia type ascus) ... 94
93. Growing directly on rock ... 95
94. Thallus of coarse granular areoles; KOH+ granules mostly in hypothecium; ascospores mostly not septate ... "Lecidea" berengeriana (Massal.) Nyl.
94. Thallus ± continuous, thinner; KOH+ granules in exciple and hypothecium; ascospores often 1-septate ... "Lecidea" hypnorum Libert
95. Thallus well developed, rimose or ± bullate areolate ... 96
95. Thallus not or scarcely visible; exciple carbonaceous; upper hymenium greenish; ascospores halonate, 13-28 x 7-14 µm ... Farnoldia jurana (Schaerer) Hertel
96. Medulla IKI+ deep purple; thallus rimose; apothecia sunken to emergent; ascospores 11-15 x 6-7 µm ... Porpidia speirea (Ach.) Kremp.
96. Medulla IKI-; thallus ± bullate areolate; apothecia sessile; ascospores 14-23 x 7-11 µm ... Porpidia calcarea Gowan
97(78). Ascomata discoid ... 98
97. Ascomata elongated (lirelline); hymenial gel IKI+ orange; asci IKI+ orange with a tiny blue ring in apex; photobiont Trentepohlia (Opegrapha) ... 111
98. Ascospores submuriform/muriform; photobiont Trentepohlia ... 99
98. Ascospores transversely septate only ... 101
99. Apothecia sessile with thick margin and vertical sides or even ± constricted at base; young apothecia flask-like opening by a pore, gradually expanding to an urceolate apothecium; disk pinkish or orangish; thallus often pinkish ... 100
99. Apothecia immersed with a whitish, thin, uniform margin which is rarely raised above the level of the disk, very rarely emergent with a thicker, sloping margin; disk whitish, sometimes with very pale yellowish or pinkish tints to pale tan; thallus whitish, mainly endolithic; contents of ascus between spores dark blue with iodine; ascospores irregularly ca. 5-7 x 3-4-septate, 18-24(-27) x 9-12(-14) µm; mostly dry overhung vertical faces, apparently common, Alabama, Illinois, Kentucky and Missouri; type collection is from Bermuda, reported from Tennessee by Vezda (1965) ... Petractis farlowii (Nyl.) Vezda (Immersed apothecia seem to be the only character which P. farlowii has in common with the generitype, Petractis clausa (Hoffm.) Kremp., which is a very odd species. Personally, I would rather place it in the still heterogeneous Gyalecta.)
100. Lower part of hymenium colorless; ascospores irregularly 3-5 x 2-3-septate, 13-25 x 6-10 µm; widespread but not common? ... Gyalecta jenensis (Batsch) Zahlbr.
100. Lower part of hymenium yellow; lower cells of paraphyses swollen, ± moniliform, containing bright orange (I+ green-black) carotenoid drops; ascospores irregularly ca. 3-5 x 1-3-septate, 13-20(-22) x 7-9(-11) µm; on wet cliff face; Missouri ... Gyalecta sp. (Gyalecta jenensis var. montenegrina Servít is said to have hymenial carotenoids and a similar spore size. I have seen no material of this taxon for comparison. As to the American material, I would suggest that the carotenoid character, since it is associated with physical modification of the paraphyses, might indicate recognition as a separate species.)
101(98). Ascospores 2-celled ... 102
101. Ascospores 4-10-celled ... 107
102. Growing on rock ... 103
102. Growing on bryophytes see " Lecidea" hypnorum above (94)
103. Ascomata with thalline margin and/or proper margin; asci elongated ... 104
103. Ascomata lacking margin; asci ± globose; photobiont chlorococcalean; ascospores 10-17 x 4-6 µm ... Arthonia lapadicola (Taylor) Branth & Rostrup
104. Thalline margin absent; ascus Catillaria type ... 105
104. Thalline margin present; ascus Bacidia or Teloschistes type ... 106
105. Paraphysis tips swollen, with a distinct brown cap, KOH-; exciple with brown outer layer similar to paraphysis tips; hypothecium colorless; ascospores 8-12 x 3-4 µm ... Catillaria lenticularis (Ach.) Th. Fr.
105. Paraphysis tips lacking brown cap but epihymenium pigmented, KOH+ purplish; exciple and hypothecium purple-black; ascospores 9-13 x 3.5-5.5 µm ... Catillaria tristis (Müll. Arg.) Arnold
106. Ascospores polarilocular, 14-17 x 7-8.5 µm; epihymenium often KOH+ purplish; thallus gray, cracked areolate; disk brown, not pruinose ... Caloplaca alboatra (Tuck.) Zahlbr.
106. Ascospores not polarilocular 10-13 x 5-5.5 µm; thallus tan, areolate to almost subsquamulose; disk brown, weakly pruinose; epihymenium KOH- ... Lecania perproxima (Nyl.) Zahlbr.
107(101). Ascospores short cylindrical or fusiform, 4-8-celled ... 108
107. Ascospores needle-shaped, slender, ultimately 8-10-celled but septa late to develop and hard to see ... 110
108. Growing on rock ... 109
108. Growing mostly on bryophytes but occasionally directly on rock; apothecia soon ±globose, gray-brown, black or occasionally pallid; hypothecium pale to dark brown; epihymenium greenish or pale; ascospores 4-8-celled, with punctate sheath, 18-27 x 5-6 µm ... "Bacidia" sabuletorum (Schreber) Lettau
109. Apothecia usually remaining flat often with ± raised margin, blackish; hypothecium/exciple dark brown; epihymenium greenish; ascospores 4-celled, 11-19 x 3-4 µm ... Bacidia granosa (Tuck.) Zahlbr.
109. Apothecia tan, remaining ± flat with dark brown margin or swollen with excluded margin and then disk often mottled brown at edges; hypothecium/exciple colorless or exciple purple brown; epihymenium colorless; paraphyses clavate-capitate; ascospores 4-celled, 18-21 x 3 µm; Missouri ... Lecania cuprea (Massal.) v. d. Boom & Coppin
110(107). Growing on plant remains or bryophytes; epithecium dark green, olivaceous or pale; hypothecium brownish; exciple red brown, KOH+ purplish above, becoming paler below; ascospores (6-) 7 (-10)-celled, 30-45 x 1.5-3 µm ... Bacidia bagliettoana (Massal. & De Not.) Jatta
110. Growing on rock; epithecium greenish or pale; hypothecium brown; exciple mostly pale within, greenish outside; ascospores 4-8-celled, 20-35 x 2-3 µm ... Bacidina egenula (Nyl.) Vezda ?
111(97). Ascospores varia type, 20-32 x 4-5(-6) µm, mostly 6-celled ... Opegrapha mougeotii Massal.
111. Ascospores vulgata type, 23-35 x 3-4 µm, 6-8-celled ... Opegrapha lithyrga Ach.
112(77). Ascospores 2-celled ... 113
112. Ascospores 4-celled or submuriform; thallus well developed; apothecia initially immersed, emergent, often with a thalline margin; ± norstictic acid (sometimes placed in segregate genus, Diplotomma) ... 114
113. Thallus usually endolithic; ascospores with septum thickened and outer wall with a darker median band; 15-21 x 9-13 µm; apothecia sessile, often with thalline margin; no lichen substances ... Rinodina bischoffii (Hepp) Masssal.
113. Thallus gray, ± flat, scattered areoles; xanthone?, norstictic acid agg.; apothecia and ascospores ± as in Amandinea punctata, ca. 8-10 x 4.5-5.5 µm; on lime rock but upper layer is HCl- (calcium mostly leached out?); Jefferson and Ozark counties, Missouri ... Buellia sp.
114. Ascospores 4-celled, 16-20 x 6-9 µm ... Buellia venusta (Körber) Lettau
114. Ascospores submuriform, 14-17 x 7.5-9 µm ... Buellia alboatra (Hoffm.) Th. Fr.
115(76). Apothecia immersed in thallus or thallus reduced to a narrow margin around apothecium (check x-section if necessary) ... 116
115. Apothecia sessile, without thalline margin; thallus endolithic ... 125
116. Thallus or apothecial margin brownish or grayish ... 117
116. Thallus yellow or yellowish white due to coating of white pruina; pruina variable, with pruina only on and around brownish apothecia or densely covering thallus and concealing apothecia; areoles scattered or contiguous; ascospores broadly ellipsoid, 4-5 x 2.5-3 µm; probably only weakly calciphilous; Missouri ... Acarospora heufleriana Körber
117. Ascospores large, 7-19 x 3.5-10 µm, fewer than 100/ascus ... 118
117. Ascospores smaller, 4-6 x 1.5-3 µm, more than 100/ascus ... 119
118. Thallus areolate, brown or olive brown; areoles contiguous or dispersed, usually only one hymenium/areole, often filling areole and appearing lecanoroid; hymenium usually immersed but occasionally ± sessile and lecanoroid; ascospores broadly elliptical or ovate, 11-15(-19) x 8-11 µm; paraphyses with endcell(s) swollen, 3.5-4.5 µm across; on siliceous rocks according to Magnusson, New York alvar specimens on HCl- pebbles, Michigan material on lime pebbles? ... Acarospora oligospora (Nyl.) Arnold
118. Usually several hymenia/areole; ascospores elliptical, 7-12 x 3.5-6 µm; paraphyses not swollen at tips ... Acarospora macrospora (Hepp) Bagl.
119. Areoles or apothecia larger, 1-4.5 mm across, densely pruinose or not pruinose; disk pruinose or not; ascospores 3.5-5.5 x 1.5-2 µm (Acarospora glaucocarpa (Ach.) Körber s. lat., three "taxa"? in New York and a fourth in Missouri.) ... 120
119. Areoles small, ca. 0.5 mm; thallus not pruinose; disk pruinose ... 123
120. Thallus areolate or continuous; apothecial disk and margin pruinose ... 121
120. Thallus squamulose, brown to olivaceous with slightly upturned white pruinose margin; squamules crowded, often slightly imbricate, irregular, even somewhat lobe-like, with thick medulla and thick cortex which extends into and breaks up the algal layer; often sterile, when fertile, apothecia immersed with brown, epruinose disk ... Acarospora cervina Massal.
121. Thallus of contiguous or ± dispersed areoles ... 122
121. Thallus continuous to rimose areolate; apothecia large, resembling those of Sarcogyne regularis but lecanoroid in section; margin gray pruinose; disk bluish or grayish pruinose ... Acarospora glaucocarpa (type 2)
122. Thallus of small, irregular, strongly white or grayish pruinose areoles, occasionally slightly lobed at margin when very well developed; apothecia sessile, lecanoroid; disk whitish or grayish pruinose (nearest A. glaucocarpa s. str.?) ... Acarospora glaucocarpa (type 1)
122. Thallus of orbicular to polygonal ± raised areoles, grayish, epruinose, slightly shiny, forming a ring around apothecium; one apothecium per areole; disk brown to blackish, often surrounded by a concolorous ring; ascospores 4-6 x 1.5 µm; Ozark County ... Acarospora glaucocarpa (Missouri type)
123(119). Thallus not obvious or only scantily developed ... 124
123. Thallus usually well developed, gray or pale tan, rarely not evident; fertile areoles often ± lecanoroid (hymenium occasionally immersed in forms with thick thallus) disk blackish; thalline rim whitish and tending to disappear; paraphyses ± thick with end cells enlarged, 4-4.5 µm in diameter; ascospores 4-6 x 2-2.2 µm; Michigan [sp. #2 of Straits Region, needs to be restudied] ... Acarospora sp.
124. Areoles usually grayish tan, scattered to ± contiguous; often only a single hymenium/areole; disk pale greenish pruinose; ascospores 3.5-5 x 1.7-2 µm ... Acarospora immersa Fink
124. Areoles brown, often becoming lecanoroid, scattered or contiguous; disk brown, epruinose; ascospores 3-5 x 1.5-2 µm ... Acarospora canadensis H. Magn. [Thallus tan (when present); fertile areoles scattered, strongly lecanoroid; disk brown, rarely weakly pruinose; rim tan, persistent; paraphyses slender, end cells slightly enlarged, 3-3.5 µm in diameter; ascospores 4-5.5 x 1.8-2 µm; Michigan. Acarospora sp. #1 of Straits Region, possibly the same as A. canadensis, material needs to be restudied]
125(115). Inner part of exciple colorless or brown ... 126
125. Inner part of exciple green; otherwise similar to S. regularis; known from a single collection from Estill County, Kentucky ... Sarcogyne sp.
126. Disk black or reddish, epruinose or thinly pruinose ... 127
126. Disk with thick, stark white pruina; margin black, ± epruinose, strongly raised; apothecia large, ca. 1 mm across; paraphyses thick, ca. 6 µm across at tips with broad locule, ca. 5 µm across, appearing moniliform; ascospores ca. 4-5 × 2.5 µm; pycnidia not found ... Sarcogyne sp.
127. Disk reddish, even when dry, epruinose; margin black, slightly raised; apothecia sometimes curling away from rock exposing white medulla filled with small crystals; exciple similar to above except for lower part densely filled with small crystals; ascospores 4-5 × 2-2.5 µm; Nebraska ... Sarcogyne novomexicana H. Magn. ?
127. Disk black or slightly reddish, usually pruinose, occasionally epruinose; pruina thin, whitish; margin usually raised, occasionally disappearing, black, usually epruinose, occasionally thinly pruinose; rarely whole apothecium moderately pruinose; apothecia variable in size, ca. 0.5-1 mm across; exciple mostly pale within, dark brown outside, often only above adjacent to hymenium, composed of rather large, radiately arranged cells; ascospores ca. 4-6 × 2-3 µm; pycnidia inconspicuous, ± globose; conidiospores elliptical to elliptic-oblong, 2.5-3.5 × 1-1.5 µm (Sarcogyne regularis s. lat.) ...128
128. Apothecia sessile ... Sarcogyne regularis Körber (s. str.?)
128. Apothecia sunken in limestone, ±flush with surface, with external aspect of a Verrucaria, 0.3-0.7 mm diam, thin, ca. 0.1 mm in center; margin black, slightly raised above disk; disk blackish, weakly to moderately whitish pruinose; epithecium yellow-brown; exciple dark brown outside, paler brown inside (pigment mainly between hyphae); ascospores 5-7 x 2-2.5 µm; thallus white; Taney County, Wetmore 68706 (MIN) ... Sarcogyne sp. (S. regularis s. lat.)
129(75). Paraphyses persistent; hymenial gel I- (pale yellowish) ... 130
129. Paraphyses absent or dissolving, hymenial gel I+ blue-green or orangish ... 131
130. Asci cylindrical with spores in a single row; ascospores ellipsoid with rounded ends, minutely granular ornamented, 13-17 x 7-8.5 µm ... Acrocordia conoidea (Fr.) Körber
130. Asci narrowly elliptical/obovate with spores irregularly arranged; ascospores ovate to ± elliptical, 13-18 x 5.5-7 µm; rock near/in water ... Anisomeridium carinthiacum (J. Steiner) R. C. Harris
131. Growing on rock ... 132
131. Growing on mosses; areoles small, sessile, shiny, green, corticate; cortex papillate; ascomata black, pyriform, between areoles; ascospores 8/ascus?, colorless, muriform, 45-60 x 18-20 µm; no hymenial algae; Missouri ... Agonimia sp.
132. Hymenial algae present; ascospores muriform ... 133
132. Hymenial algae absent; ascospores various ... 137
133. Asci with 1-2 spores ... 134
133. Asci with 8 spores; ascospores colorless, 5-7 x 1-2-septate, 15-22 x 9-12 µm; thallus tan to brown, angular areolate, with black tip of ascoma visible in middle of areole ... Staurothele diffractella (Nyl.) Tuck.
134. Thallus epilithic, pale tan to dark brown ... 135
134. Thallus endolithic, only ascomatal wart visible, ca. 0.07 mm across; ascospores dark brown, ca. 8 x 3-septate, 33-62 x 18-33 µm ... Staurothele elenkinii Oksner
135. Marginal areoles not radiately arranged ... 136
135. Marginal areoles radiate, narrow, strongly convex, dark brown; central areoles thicker and larger; ascospores brown, ca. 9 x 3-septate, 24-50 x 11-21 µm ... Staurothele drummondii (Tuck.) Tuck.
136. Thallus of scattered, flat, weakly effigurate, pale tan areoles; ascospores ± colorless, 40-60 x 15-25 µm ... Endocarpon pusillum Hedwig
136. Thallus of angular contiguous areoles, dull-greenish brown to orange-brown; ascospores brown, 7-8(-12) x 2-3-septate, 26-60 x 10-26 µm; Minnesota ... Staurothele monicae (Zahlbr.) Wetmore
137(132). Ascospores 1-3-septate or submuriform-muriform ... 138
137. Ascospores not septate (Verrucaria, probably the largest genus on lime rocks. The treatment here is very sketchy including only some of the more distinctive species.) ... 144
138. Ascospores submuriform-muriform (Polyblastia) ... 139
138. Ascospores 1-3-septate (Thelidium) ... 140
139. Growing over bryophytes and soil; thallus dark brown with lighter brown-gray areole-like areas; ascomata black without a clypeus, ca. half immersed; ascospores 8/ascus, colorless, 30-60(-75) x 15-25(-30) µm (Purvis), 35-50 x 13-17 µm in New York alvar collection ... Polyblastia gelatinosa (Ach.) Th. Fr.
139. Growing on rock; thallus not evident; ascomata black, shiny, ± globose, ca. half immersed; ascomatal wall black, entire, entire; ascospores 8/ascus, colorless, 15-17 x 8.5-9 µm; Drummond Island, Michigan ... Polyblastia intermedia Th. Fr.?
140. Clypeus present; ascomata not forming pits in rock ... 141
140. Clypeus absent; ascomata forming pits in rock or not ... 142
141. Ascospores 3-septate, 30-55 x 13-21 µm; ascomata 0.4-0.7 mm across ... Thelidium papulare (Fr.) Arnold
141. Ascospores 1-septate, 18-30 x 9-15 µm; ascomata 0.3-0.7 mm across ... Thelidium pyrenophorum (Ach.) Mudd
142. Ascomata superficial; thallus usually epilithic, shades of brown ... 143
142. Ascomata immersed in pits in rock; thallus endolithic, whitish or not evident; ascospores 3-septate, 30-55 x 11-17 µm ... Thelidium incavatum Mudd
143. Ascospores 3-septate, 25-37 x 9-15 µm ... Thelidium zwackhii (Hepp) Massal.
143 Ascospores 1-septate, 17-29 x 7-12 µm; Michigan ... Thelidium minutulum Körber
144(137). Thallus white, gray or brown ... 145
144. Thallus reddish or purplish; ascomata etching pits in rock; wall dark only at apex; ascospores 20-30 x 13-17 µm ... Verrucaria marmorea (Scop.) Arnold
145. Thallus pale (shades of white, pale gray or pale tan), endolithic to epilithic, continuous to rimose or weakly rimose-areolate ... 146
145. Thallus dark (gray, brown or greenish), epilithic, continuous, rimose or rimose-areolate, or with dispersed areoles ... 150
146. Exciple and/or clypeus black, forming an entire "perithecial wall" ... 147
146. Exciple colorless; clypeus black, dome-shaped; "wall" lacking at base ... 149
147. Ascomata immersed, etching pits in the rock ... 148
147. Ascomata mostly ca. half immersed with dome-like clypeus in addition to thin, entire, black exciple; ascospores 19-23(-27) x 11-13(-15) µm ... Verrucaria calkinsiana Servít
148. Clypeus forming a small apical disk, smaller in diameter than the deeply immersed hymenium; thallus thin, whitish or endolithic; ascospores mostly not developed, seen only in two collections from southern Indiana, 18-22 x 9-12 µm (close to size given for European material) (Bagliettoa) ... Verrucaria baldensis Massal. s. lat.
148. Clypeus absent/fused with exciple?; ascoma subspherical; wall thin, ± uniform; thallus not evident; ascospores 20-22 x 8-11 µm ... Verrucaria calciseda DC.
149(146). Clypeus not flattened, ± hugging the centrum; ascospores large, 27-32 x 14-16 µm ... Verrucaria muralis Ach.
149. Clypeus spreading, flattened, not hugging the centrum; ascospores smaller, 14-19 x 9-11 µm ... Verrucaria illinoisensis Servít
150(145). Black prothallus at margin or areoles with well developed black "medulla" or basal layer; ascomatal wall entire, usually fusing with black basal layer ... 151
150. Black prothallus/basal layer, absent or poorly developed or prothallus pale ... 154
151. Thallus continuous and rimose or rimose-areolate ... 152
151. Thallus dispersed areolate, brown or gray brown, thick; ascospores 13-21 x 6-7.5 µm; ascomatal wall pale except at apex; medulla black below, colorless above (not a species I know, couplet stolen from Brodo (1988) ... Verrucaria glaucovirens Grummann
152. Thallus gray to brownish gray; ascospores under 20 µm long ... 153
152. Thallus shades of brown or dark brown, often irregularly mottled with black; ascospores 19-28 x 8-16 µm;; areoles not black-edged; lower half of areole section black ... Verrucaria nigrescens Pers.
153. Ascospores small, 11-14 x 6-7 µm; ascomata, pycnidia or sterile columns of black "medulla" visible as many small black dots on areole surface; thallus thick, rimose-areolate, pale to medium brownish gray; areoles, flat, often black-edged ... Verrucria fayettensis Servít (iowensis Servít)
153. Ascospores variable 10-19 x 6-8 µm; areoles with 1-few larger black ascomata (not with small black dots); thallus brown with black "medulla", a thin black line at base of areole or pale ... Verrucaria glaucina auct. ( Missouri material extremely variable as to ascospore size and development of black basal layer, seems to fall into what has been variously called V. fuscella or V. glaucina. Probably easiest to follow British and use V. glaucina auct. Differs from V. nigrescens s. lat. only in ascospore size?)
154(150). Ascospores small, 15 x 7 µm or less; ascomata small, ca. 0.1-2 mm across, immersed, difficult to see or visible as small black dots on areole surface ... 155
154. Ascospores large, 16 x 13 µm or larger; ascomata ± large and readily visible ... 156
155. Thallus dark brown, strongly areolate; areoles contiguous or occasionally solitary, irregular, thick, widening from a narrower base (subumbilicate?), and therefore ± easily broken off the rock; mostly ending abruptly but occasionally with a few smaller, flatter marginal areoles, in section appearing compound above but thick, white medulla ± continuous; hypothallus not evident; ascomata completely immersed (small black ostioles nearly invisible); ascomatal wall colorless except at mouth; ascospores ca. 13-15 x 7-8 µm. Abundant in N.Y. alvars, could be confused with Staurothele drummondii. Because of the very thick thallus this species was once included in Dermatocarpon. Very similar material from Jefferson Co., Missouri has ascospores only 5.5-6 µm wide ... Verrucaria compacta (Massal.) Jatta s. lat. (Included in Esslinger & Egan as Catapyrenium, synonymized by Santesson (1993) with V. fuscula Nyl., Breuss (Östrerr. Zeitschr. Pilzkunde 3: 15-20. 1994) recognizes both species in Verrucaria. I, however, have not been able to locate conidia and am not otherwise smart enough to tell which species American material belongs to (or neither?).
155. Thallus thin, olive to brown-gray, granulose to minutely areolate; ascospores 12-15 x 6-7 µm (14-25 x 4-6 µm fide Brodo, 1988) ... Verrucaria nigrescentoidea Fink
156. Thallus olive brown or grayish ... 157
156. Thallus dark brown; ascospores 21-24 x 13-16 µm ... Verrucaria nigrescens Pers. s. lat.
157. Thallus light to ± dark olive brown, usually slightly shiny, rimose-areolate; mostly with each areole having a single ± central ascoma; ascomata half to almost entirely immersed in thallus; black clypeus extending to base of ascoma, pale below or with exciple darkening also; ascospores 16-23 x 8-11 µm ... Verrucaria sp.
157. Thallus dirty gray; ascomatal wall weakly melanized except at apex, ± entire; ascospores 16-22 x 13-16 µm (not known to me, data from original description) ... Verrucaria finkiana Servít ?
158(72). Apothecia and thallus KOH+ purple (Caloplaca, another big genus which I do not understand well. Expect problems.) ... 159
158. Apothecia and scanty thallus KOH-; ascospores 8/ascus, not polarilocular ... Candelariella aurella (Hoffm.) Zahlbr.
159. Thallus sorediate or thallus entirely sorediate ... 160
159. Thallus not sorediate ... 163
160. Thallus with distinct soralia or at least some corticate areoles present ... 161
160. Thallus composed entirely of granular soredia, dull brownish yellow, (sometimes placed in the segregate genus Leproplaca) ... Caloplaca chrysodeta (Räsänen) Dombr.
161. Thallus not placodioid ... 162
161. Thallus of radiating lobes, placodioid, orange with bright yellow laminal soralia ... Caloplaca cirrhochroa (Ach.) Th. Fr.
162. Soredia diffuse, often obscuring areoles; bright yellow (almost green in deep shade) ... Caloplaca citrina (Hoffm.) Th. Fr.
162. Soredia in ± delimited soralia; thallus areolate, orange ... Caloplaca obliterans (Nyl.) Blomb. & Forss.
163(159). Thallus not of radiating lobes or thallus not evident ... 164
163. Thallus of radiating lobes, placodioid, short, broadening at the tips, dull orange, not corticate below (lobes narrow, brighter orange, corticate below see Xanthoria above) ... Caloplaca saxicola (Hoffm.) Nordin
164. Growing on rock or on lichens on rock ... 165
164. Growing on bryophytes and lichens on soil; thallus white; apothecia rusty orange to dark brown, with a thin whitish margin (at least when young); ascospores 12-22 x 6-12 µm ... Caloplaca sinapisperma (Lam. & DC.) Maheu & Gillet
165. Ascospores polarilocular ... 166
165. Ascospores not polarilocular, not septate; thallus endolithic or ± continuous, whitish; apothecia hemispherical, adnate, dull orange; ascus Porpidia type ... Protoblastenia rupestris (Scop.) J. Steiner
166. Thallus yellow or orange, conspicuous ... 167
166. Thallus inconspicuous or absent; apothecia dull orange to orange-brown with paler margin; ascospores 14-16(-19) x 6-8 µm; isthmus narrow, 2-3 µm ... Caloplaca feracissima H. Magn.
167. Thallus areolate or confined to a few subsquamulose areoles near apothecia ... 168
167. Thallus continuous or areolate, yellowish, often discolored by ?; apothecia ± bright orange; ascospores 12-15 x 6-8 µm; isthmus 3-7 µm (mostly over 4.5 µm) ... Caloplaca flavovirescens (Wulfen) Dalla Torre & Sarnth.
168. Growing, at least initially, on Staurothele and possibly Verrucaria; thallus a few subsquamulose areoles around apothecia, bright orange or not evident; apothecia with thalline margin and disk bright orange (± concolorous with thallus when present) ... Caloplaca sp.
168. Thallus areolate, with ± lobate margin, deep yellow to yellowish orange; apothecia with orange disk and ± concolorous margin; ascospores 10.5-14 x (4.5-)6-7.5 µm; isthmus (2-)3-4(-4.5) µm ... Caloplaca velana (Massal.) DuRietz
Attempting to make a key for this group truly brings home the realization that there is no other group of lichen-forming fungi in such taxonomic disarray. What follows is probably more fiction than fact. The following are said to occur on calcareous rocks, mostly from the western and southwestern edges of our area. I know nothing about them and therefore do not include them in the key.
Lichinella minnesotensis (Fink) Essl. Peccania kansana (Tuck.) Forss.
Metamelaena melambola (Tuck.) Henssen Peccania texana (Tuck.) Wetmore
Paulia pyrenoides (Nyl.) Henssen Pyrenopsis viridirufa Tuck.
169(71). Photobiont Nostoc; ascospores not septate ... 170
169. Photobiont not Nostoc (scytonemoid or chroococcoid) ... 172
170. Thallus cushion-like growing from a central point or umbilicate ... 171
170. Thallus ± foliose, dark brown to black, anastomosing, with large irregular to subglobose warts and often with thick ridges, mostly only lobe ends flattened; growing draped over and through moss cushions on rock; apothecia often numerous, very inconspicuous, immersed with pore-like disk; ascospores thick-walled, subglobose to broadly ellipsoid, 13-15 x 9-10 µm ... Lempholemma polyanthes (Bernh.) Malme
171. Thallus a cushion of ± elongated lobes with swollen ends; usually sterile (see description and illustration in Purvis, pp. 342,343) ... Lempholemma cladodes (Tuck.) Zahlbr.
171. Thallus discoid, umbilicate; margin irregularly crenate or lobed, small, ca. 0.3-0.5 mm across; apothecia not seen by me but reported to be by Tuckerman to be lecanorine; ascospores 16-20 x 7-8 µm ... Lempholemma umbella (Nyl.) Fink
172(169). Thallus of ± flat areoles or radiating lobes attached by rhizines; lower side often blue-green; photobiont scytonemoid; ascospores septate (Placynthium) ... 173
172. Thallus filamentous and photobiont Scytonema or crustose and areolate to subfoliose or subfruticose and photobiont chroococcoid; rhizines lacking; lower side not blue-green; ascospores not septate ... 177
173. Apothecia with proper margin; underside of thallus blue-green ... 174
173. Apothecia with thalline margin; lobes filiform with colorless underside; sometimes isidiate ... Placynthium stenophyllum (Tuck.) Fink
174. Thallus areolate-squamulose, usually with conspicuous blue-green tinted blackish prothallus ... 175
174. Thallus stellate-radiating without dark prothallus ... 176
175. Ascospores 9-18 x 3.5-5.5 µm; dry limestone ... Placynthium nigrum (Hudson) Gray
175. Ascospores broader, 10-13(-20) x 6-8 µm; moister habitats ... Placynthium tantaleum (Hepp) Hue
176. Lobes more than 0.2 mm across; thallus dying off in center, then thallus ring-shaped, rarely isidiate; ascospores 2-celled ... Placynthium petersii (Nyl.) Burnham
176. Lobes 0.05-0.2 mm across, filiform or canaliculate, shining, granulose or isidiate; ascospores 2-4-celled ... Placynthium asperellum (Ach.) Trevisan
177(172). Thallus not filamentous ... 178
177. Thallus filamentous without any special attachments to substrate, cushion-forming; filaments ca. µm across; Scytonema with fungal hyphae in sheath and cells penetrated by short, capitate haustoria ... Thermutis velutina (Ach.) Flotow
178. Photobiont with a yellowish to brownish sheath (at least in outer parts of thallus), not purple in KOH ... 179
178. Photobiont with a reddish sheath KOH+ purple (Gloeocapsa); thallus ± fruticose, beginning as an obconical cushion, then dividing into mostly erect, ± lumpy cylindrical branches ... Synalissa symphorea (Ach.) Nyl.
179. Thallus crustose, areolate, brownish to blackish ... 180
179. Thallus foliose/fruticose, ± centrally attached, heteromerous; lobes strap-shaped, irregularly branched or not or small umbilicate disks ... 181
180. Asci with 8 spores; thallus of scattered or weakly aggregated areoles, often with isidioid granules, especially on margins; apothecia initially immersed becoming emergent with a thalline margin; disk usually red brown ... Psorotichia schaereri (Massal.) Arnold
180. Asci with ca. 24-32 spores; thallus forming large patches of contiguous areoles, with weakly placodioid margin; surface rough but not obviously isidiate; apothecia sessile from beginning, initially ± globose, opening to a flat apothecium with raised thalline margin; disk brown; Maryland, Minnesota ... ?
181. Thallus lobed ... 182
181. Thallus unlobed (margin at most weakly lacerate), scattered, umbilicate disks, 1-5 m diam; apothecia immersed, divided by sterile tissue; Maryland ... Lichinella?
182. Lobes strap-shaped, patchily to entirely grayish pruinose, ± smooth ... Thyrea confusa Henssen
182. Lobes fan-shaped, not pruinose, black, usually granular isidiate ... Lichinella nigritella (Lettau) Moreno & Egea