2a Thallus, when fully developed, with apothecia, which may be sometimes with poorly developed hymenium and superficially soralium-like; additionally soralia or isidia may be present --- 3
2b Thallus normally without apothecia; soralia, isidia or nodulose excrescences mostly present --- 90

3a Ascospores dark at maturity ("Melanaria") --- 4
3b Ascospores persistently colourless (Pertusaria s.str.) or ascocarps usually absent --- 8

4a Ascospores 1/ascus, c. 150-240 x 50-90 µm --- 5
4b Ascospores 2-4/ascus, smaller --- 6

5a Ascospores 160-240 x 60-90 µm, finally completely greenish grey; thallus whitish grey, smooth, more or less rimose-areolated, areoles 1-2.5 mm wide; fertile warts not clearly differentiated, discs punctiform, black, to 40/areole; on rock, E Pyreneans, Corsica, Macedonia --- P. spilomantha Nyl.
5b Ascospores c. 150-180 x 50-70 µm, pale brown, with reticulate striae;. thallus pale grey, continuous, warty; thallus P-, K-, C-, KC-, UV-; indet. fatty acids; apothecia becoming crater-like, lecanorine, abundant and confluent, basally constricted, 1-2 mm diam.; disc lilac-brown, flat to concave, white-pruinose; on Quercus tree base in Spain --- 3/P. sp. 2 (Giralt 1996)

6a Apothecia in more or less clearly delimited, basally constricted, 1-2 mm wide fertile warts; discs dense, united in discs of 2^nd order surrounded by thalline margin; thallus thick, brownish grey, rimose-areolated; norstictic, gyrophoric, connorstictic acids; ascospores 110-160 x 45-95 µm; Greece --- P. pentelici J.Steiner
6b Apothecia not in fertile warts or in poorly delimited fertile warts; thallus grey, grey-whitish or sometimes creamy white --- 7

7a Thallus granularly papillose, scabrid, more or less rimose-areolated, 1-1.5 mm thick; papillae semiglobose, about 0.1 mm wide and high; discs with 2-5 together, immersed; ascospores 96-160 x 50-85 µm, with thick, colourless wall and dark, K+ violet content; on rock, Canary Islands --- P. urceolaria Nyl.
7b Thallus smooth to rugulose, more or less rimose-areolated, often granular with isidia-like, fragile, c. 0.1 mm diam. papillae leaving sorediate scars; thallus K+ orange-red, with norstictic acid; discs with several together, immersed, with slightly open, brownish black, very irregular and much divided discs; ascospores grey- or olive-black, K+ violet, 2(-4) per ascus, c. 80-100 x 55-85 µm, outer surface minutely pitted; on siliceous rock, Western Europe, ?South Tyrol --- 4/P. lactescens Mudd

8a (3) Apothecia when fully developed with distinctly widened discs, not perithecium-like --- 9
8b Apothecia persistently perithecium-like, with punctiform discs (ostioles), one or several in each fertile wart --- 47

9a Fertile warts soralium-like, with granularly laciniate, more or less sorediate margin and granularly pruinose discs, often with degenerated hymenium; ascospores 1-2/ascus, often poorly developed --- 10
9b Fertile warts not soralium-like, with smooth, not pruinose or slightly mealy, initially often punctiform discs; ascospores 1-8/ascus --- 33

10a On rock --- 11
10b On bark or wood --- 19

11a Thallus K+ yellow turning red --- 12
11b Thallus K- or +yellowish --- 14

12a Ascospores 1/ascus; norstictic acid present --- 13
12b Ascospores 2/ascus, c. 120-150 x 50-60 µm; norstictic acid absent, salazinic acid and fatties present; Aegean --- P. parotica Sipman

13a Thallus with norstictic acid and sometimes? with salazinic, fatty acids and xanthone, rather thick, more or less grey, warty-papillose, the warts with sorediate openings; fertile warts to about 1.5 mm wide with 1-4 blackish discs; ascospores 1/ascus, about 100-300 x 50-100 µm; Mediterranean-Atlantic, from Wales and Ireland to Greece; primary species of P. excludens --- 4/5/P. monogona Nyl.
13b Thallus with norstictic and picrolichenic acids, areolated, areoles 0.2-0.5 mm wide; fertile warts 1-1.8 mm wide, prominent, with 1-3 discs, soralia-like; disc black with white pruina; ascospores 1/ascus, 100-150 x 35-50 µm, with strongly striate wall; on siliceous rock near Tanger, also in Spain (Boqueras 2000); primary species of P. teneriffensis --- P. ludovicae Werner

14a Thallus without isidia, sometimes with soralia, more or less grey, K- or K+ brownish; fatty acid iH; on sandstone in border area Saxony/Bohemia/Silesia --- 5/P. ocellata (Wallr.) Koerb.
14b Thallus without isidia and soralia, K- or K+ brownish; protocetraric acid; on siliceous stone in the Aegean, Greece --- 12/P. pseudoparotica Sipman
14c Thallus with coralloid isidia or with columnarly elongated warts --- 15

15a Thallus with dense, columnar, often fertile warts --- 16
15b Thallus with scattered isidia or thallus warts --- 17

16a Thallus with numerous dense, columnar fertile warts occasionally apically bearing 2-5 discs, mostly apically bursting and producing soredia; fatty acids iH; Ireland --- P. polythecia (Tayl.) Erichsen
16b Thallus with numerous dense, 2-3 mm high and wide, columnar fertile warts apically bearing 2-4 black-brown discs, at first with greyish cover; ascospores 1/ascus, about 200 µm long; Spain --- P. clementeana Müll.Arg.

17a Isidia thin, about 0.1-0.3 mm thick, granular to coralloid, concolorous with thallus, pale greyish to whitish; thallus P+ yellow-orange, K+ yellow, C-, KC-, UV-; thamnolic acid; discs rare, usually in groups of 2-4 in 1.5-2 mm wide fertile warts; discs more or less brown; ascospores 2/ascus, about 80-140 x 40-80 µm; widely distributed and often frequent on boulders and outcrops of non-calcareous rock, occasionally on bark, rather variable; syn. P. subdubia --- 1/2/4/5/P. corallina (L.) Arnold
17b Isidia thicker, like thallus warts --- 18

18a Thallus smoky grey, with mammose, about 1-1.5 mm wide, dense, more or less sorediate papillae; thallus P+ red, K+ yellowish to brownish; fumarprotocetraric with or without succinprotocetraric acids; discs rare, 1-2 together on the papillae, with blackish discs; ascospores 180-200 x 60-70 µm; southern France to N. Africa; looks similar to the corticolous P. graeca (28c) --- 2/5/P. mammosa Harm.
18b Thallus without sorediate papillae, grey to smoky grey, with short-cylindrical, 0.4-1 mm wide isidia; thallus P+ red, K+ yellowish to brownish; fumarprotocetraric, tr. protocetraric acids; fertile warts more or less semiglobose, usually with 1-4 blackish discs; ascospores 1/ascus, of very variable size; on rock poor in lime, in the Carpathians, variable --- 5/P. stalactiza Nyl.
18c Thallus without isidia or soredia, pale grey, thick, coarse-wartily areolated; thallus warts basally constricted, to 3 mm high, with somewhat worn-off surface, centrally depressed; fumarprotocetraric, succinprotocetraric acids; apothecia immersed in warts, with black discs; spores unknown; central Italy --- 2/5/P. etrusca Erichsen

19a (10) Thallus, or at least soralia, K+ yellow turning red; norstictic acid present --- 20
19b Thallus not K+ yellow turning red; norstictic acid absent --- 23

20a Spores 2/ascus; thallus without sorediate excrescences; apothecia with grey-pruinose discs; ascospores about 120-150 x 60 µm; Greece --- 5/13/P. rhodiensis Erichsen
20b Spores 1/ascus; thallus with sorediate excrescences --- 21

21a Thallus yellowish white to brownish, with irregular, sorediate excrescences; apothecia immersed, with black discs; ascospores about 30-80 x 20-40 µm; Finland --- 5/P. atropallida Vain.
21b Thallus grey, without or with regular sorediate excrescences --- 22

22a Thallus thin, long remaining endophloeodic, covered with numerous whitish-sorediate, 0.6-1 mm wide, convex warts, which partly bear a single blackish, white-pruinose disc; ascospores 200-300 x 50-100 µm; France --- 5/P. monogoniza Nyl.
22b Thallus epiphloeodic, often granular-warty, thin, not rimose, more or less grey; fertile warts flat, almost of lecanorine appearance, usually with a single, widely open, black, usually pruinose disc; ascospores about 70-150 x 25-40 µm; rare in humid sites in Bavaria --- 5/P. waghornei Hulting

23a Thallus (medulla) K+ yellow, P+ yellow to orange, thin, more or less endophloeodic, grey to whitish; thamnolic acid; fertile warts numerous, about 1 mm wide, with usually a single reddish disc; ascospores (1-)2/ascus, (38-)94(-160) x (18-)36(-58) µm, often not well developed; rare in western and central Europe; syn. P. laevigata (Nyl.) Arnold --- 1/2/5/P. trachythallina Erichsen
23b Thallus K- or K+ indistinctly yellowish or brownish --- 24

24a Thallus C+ red; fertile warts of lecanorine appearance, with usually a single reddish disc --- see P. velata 44a
24b Thallus C- --- 25

25a Ascospores 2/ascus, about 100-150 µm long; thallus whitish, rimose to radiate-plicate; thiophaninic acid, sometimes with confluentic and/or 2'-O-methylperlatolic acid; fertile warts to 1 mm wide, usually with several (-8) dark discs; thallus K and P almost -; Mediterranean --- 5/P. ilicicola Harm. --- 25
25b Ascospores 1/ascus --- 26

26a Discs reddish; thallus P+ red or at least KC+ pink or violet, not orange --- 27
26b Discs grey to black; thallus P-, KC- or KC+ orange --- 29

27a Medulla KC+ violet; thallus P- but soralia P+ orange-red to red; picrolichenic acid; fertile warts strongly convex, usually with a single brownish disc; ascospores about 220-350 µm long; thallus usually without soralia; on deciduous trees in Central Europe, more common in the Mediterranean; status uncertain, seems distinct in Mediterranean but is usually synonymized elsewhere; syn. P. amara var. slesvicensis --- 2/P. slesvicensis Erichsen
27b Medulla KC+ pink; thallus P+ orange-red to red; picrolichenic acid absent --- 28

28a Thallus rather thick, shelf-like areolate, bluish grey; physodalic, tr. protocetraric acids; fertile warts white, usually with a single, reddish disc; ascospores about 90-200 µm long; on smooth bark, often Fagus or Abies, in subatlantic parts of western Europe, extending to the Baltic Sea and the northern Alps; syn. P. leptospora Nitschke --- 1/2/4/5/P. multipuncta (Turner) Nyl.
28b Thallus rather thick, more or less rimose-areolated; fertile warts little emergent, with 1-5 small, (pale- to) dark brown discs; ascospores about 150-230 µm long; thallus K+ reddish, P+ deep yellow, the warts P+ orange; atlantic part of Central Europe, rarely found; =P. multipuncta? --- 7/P. laureri Erichsen
28c Thallus whitish grey with strong, 0.5-1 mm wide papillae and apothecium-like, 1.5-3 mm wide fertile warts and - sorediate warts; discs usually several together, to 1.5 mm wide; ascospores about 160-280 x 50-80 µm; fertile warts and medulla P+ red; fumarprotocetraric with + succinprotocetraric or protocetraric acids; several times found in Greece, Sardinia, Corsica; looks like corticolous form of P. mammosa --- 2/5/P. graeca Erichsen

29a Thallus KC-, UV-, fatty acids --- 30
29b Thallus KC-, UV-, no substances present; ascospores about 200 m long; thallus epiphloeodic, pale ashy grey, finely rimose-areolate; fertile warts about 1 mm wide, with a single blackish disc; Italy, Crete --- 1/5/P. cf. rhodiensis Erichsen
29c Thallus KC+ pink, UV-, fumarprotocetraric acid;  discs dark-brown or black, level to sunken, c. 0.4 (0.1-0.87) mm wide, usually single, initally white-pruinose, later pruinose-sorediate to sorediate; ascospores cylindric, (66-)134(-196) x (21-)46(-69) mu;  reported from Spain (Boqueras 2000) --- P. multipunctoides Dibben
29d Thallus KC+ orange, UV+ orange-red, thiophaninic with planaic or confluentic acids --- 32

30a Medulla J+ blue; thallus thin, at first endophloeodic, smooth to warty; thallus K, C and P-; fertile warts to over 1 mm wide with a single, deeply immersed, blackish disc; ascospores about 90-140 µm long; so far only near Gdansk, on Betula; =P. ophthalmiza?? --- P. brachyspora Erichsen
30b Medulla J- --- 31

31a Thallus flat, not areolated, thin to rather thick, not sorediate; fertile warts more or less regularly distributed, flat, 0.5-1 mm wide, usually with 1-2, greyish pruinose to blackish, to 0.5 mm wide discs; ascospores about 130-200 x 50-70 µm; 4 indet. fatty acids; on leached bark of e.g. Betula and Abies in oceanic and mediterranean areas, in particular in mountain forest --- 4/P. ophthalmiza (Nyl.) Nyl.
31b Thallus verrucose, not areolated, rather thick, sorediate; rarely fruiting, with scattered, about 1-4 mm wide fertile warts --- see P. albescens 141b

32a Thallus not sorediate; thiophaninic, planaic, 4-O-dimethylplanaic acids; fruits lecanorine with black disc more or less covered with thick, white pruina; epithecium greenish, K+ violet; ascospores 120-190 x (40-)60-75(-90) µm; on Juniperus in continental Spain --- 9/10/P. paramerae Crespo & Vezda
32b Thallus more or less sorediate, brownish white, more or less rimose; thiophaninic, confluentic acids; hymenium 400-500 m high; fertile warts in dense groups, to about 1 mm wide, with blackish disc and swollen thalline margin; ascospores about 150-250 x 60-90 µm; Greece --- 5/P. corinthiaca Erichsen
32c Thallus not sorediate, whitish, granular-warty-rimose; thiophaninic, 2'-O-methylperlatolic acids; fertile warts appressed, with a single blackish disc covered by white pruina composed of several apothecia; hymenium 250-300 µm; ascospores about 180-220 x 75-100 µm, with thick, smooth wall; Mediterranean --- 2/5/10/P. caesioalba (Flot.) Nyl.

33a (9) Ascospores (6-)8/ascus, usually under 50 µm long --- 34
33b Ascospores 4/ascus, about 30-60 x 25-35 µm; discs blackish; paraphyses simple to little branched; thallus whitish, P-, with dense, almost semiglobose fertile warts; no substances; on soil or bark; syn. P. freyi Erichsen --- 5/Megaspora verrucosa (Ach.) Hafellner & V.Wirth
33c Ascospores 2/ascus --- 42
33d Ascospores 1/ascus, usually over 100 m long --- 44

34a Isidia numerous, about 0.3-0.4 mm thick, 1-3 mm long, fragile, dark-tipped isidia; thallus K+ yellow becoming rusty red, P+ yellow becoming orange, C+ pink or C-, KC+ yellow-red; fumarprotocetraric, trace protocetraric or gyrophoric acids --- see P. oculata 152a
34b Isidia absent --- 35

35a On rock; thallus whitish to dark grey or brownish, P+ orange, K+ yellow to orange, C-, KC-, UV-; stictic, sometimes with tr. constictic and/or norstictic acids; fertile warts 0.5-1 mm wide, flattened, usually with several, rounded-edgy, often confluent, black, naked discs; ascospores about 20-40 x 10-25 µm; on hard, non-calcareous rock, preferably serpentine, widely distributed but usually scattered; perhaps more species involved; syn. P. inquinata (Ach.) Th.Fr., P. aspicilioides Samp. --- 1/2/4/5/11/P. chiodectonoides Bagl.
35b On bark or wood --- 36

36a On wood or on bark; ascospores rounded; thallus endo- to epiphloeodic, thin, grey, with rounded, whitish, about 0.5 mm wide soralia; thallus P+ red, K+ dirty red, C-, KC+ pink to red; fumarprotocetraric, tr. protocetraric and/or gyrophoric acid; fertile warts to 1 mm wide, Lecanora-like, with blackish, wide, scabrid disc and swollen margin; epithecium olive-green, K+ violet; ascospores about 10-15 x 8-12 µm; rare, on smooth barked trees, esp. Corylus, Sorbus, and on wood of Pinus and Betula, in Fennoscandia, Britain, Pyreneans --- 1/2/4/5/P. pupillaris (Nyl.) Th.Fr.
36b On bark; ascospores elliptic; thallus verrucose, yellowish, centrally with pulverulent-sorediate surface; K+ yellow turning red, C+ orange; thiophaninic and norstictic acids major; apothecia with dark brown disc and thick, pulverulent margin; epithecium brown, K+ violet; ascospores 4-5(-8)/ascus, biseriate, 50-70 x 25-35 µm, with smooth walls; on Quercus suber in Morocco, also in Spain (Boqueras 2000) --- 10/P. praelutescens Werner
36c On bark; ascospores elliptic; thallus KC+ yellowish or red --- 37

37a Thallus thin, usually endophloeodic, whitish-greyish, UV-; no thiophaninic acid, with gyrophoric acid; fertile warts flat but with clearly raised margin, 0.4-0.7 mm wide, with single, flesh-brownish disc and irregular margin; on smooth bark, mainly of Alnus, Betula, in Scandinavia and the Alps --- (1/2/5/P. carneopallida) 38
37b Thallus epiphloeodic, thickish, grey to strongly yellowish, UV+ orange, with thiophaninic and sometimes gyrophoric acid; Mediterranean and Atlantic --- 39
37c Thallus epiphloeodic, thin becoming warty, continuous; no substances; fertile warts hemispherical with contracted based and slightly depressed tip, 1-1.4 mm wide; ostioles usually single, black, depressed, initially punctiform, later widened to 0.5 mm; ascospores biseriate, (39-)45-60 x (21-)28-39 µm, smooth-walled; Cyprus; poorly-known taxon --- 5/P. cypriaca Erichsen
37d Thallus epiphloeodic, white to grey, irregularly warty, P+ red, KC+ red; fertile warts to 1 mm high; discs single, punctiform, later to 0.5 mm wide, blackish; ascospores 70-100 x 30-45 µm; on Quercus in Tunisia; poorly-known taxon --- P. debazaci Werner

38a Ascospores about 20-30 x 12-16 µm; Northern Europe, Scotland, Wales; --- syn. P. protuberans (Sommerf.) Th.Fr. --- P. carneopallida (Nyl.) Anzi v. cinereopallida
38b Ascospores 28-42 x 15-24 µm; Alps, Vosges, Iceland --- v. macrospora Erichsen

39a Discs blackish --- 40
39b Discs yellowish to brownish --- 41

40a Thallus strongly yellow, rather thick; fertile warts rounded, clearly raised, about 1-1.5 mm wide, with single, to 1 mm wide, flat, black disc and swollen margin; ascospores about 70-100 x 30-50 µm; on bark in the Mediterranean widespread (often included in P. hymenaea (41a))  --- 5/6/P. lecanorodes Erichsen
40b Disc blue-black, small; ascospores 50-60 x 20-35 µm; N. Africa; = P. lecanorodes?; poorly-known species --- P. lapieana B. de Lesd.

41a Thallus yellowish to ash-grey, more rarely clearly yellow, thin to rather thick; fertile warts usually frequent, often deformed, to 2 mm wide, with 1-4 deformed-rounded discs; ascospores about 60-110 x 30-50 µm; on bark of deciduous trees in well-illuminated sites in W. Europe to S. Scandinavia and the Bohemian Forest, and in the Mediterranean, absent from the Alps; syn. P. wulfenii DC --- 1/2/4/5/P. hymenea (Ach.) Schaer.
41b Thallus whitish grey, thin; K-, C-; fertile warts raised, 0.3-1.5 mm wide, lecanoroid with thick margin; disc initially round, 0.3 mm wide, later lecanoroid, pale brown; ascospores 8/ascus, 48-66 x 24-32 µm; Rumania; = P. hymenea?; poorly-known species --- P. transsilvanica Ciurchea

42a (33) Discs pale; thallus almost always endophloeodic --- see P. heterochroa 52b
42b Discs blackish; thallus K+ yellow --- 43

43a Discs single, punctiform to deformed, surrounded by lacerate thalline margin; subatlantic --- see P. pustulata 54a
43b Discs single, regularly rounded, black, 0.4-0.8 mm wide together with narrow, smooth margin; thallus thin, smooth, whitish, occasionally sorediate (v. elatina Erichsen, on conifer bark in the Alps); no substances; ascospores about 60-120 x 30-55 µm; Fennoscandia, rare in the Alps --- 1/2/5/P. stenhammari Hellb.
43c Discs single, punctiform to deformed, surrounded by smooth, slightly verrucose margin; thallus strongly yellow, thick, rimose-areolated or warted, not zoned at the margin; thiophaninic acid; fertile warts with constricted base, 1-1.2 mm wide, abundant and confluent, rounded, with initially punctiform, later to 0.5 mm wide, flat, smooth; epithecium K+ violet, C+ violet; ascospores 100-170 x 50-70 µm; on Cedrus in Morocco; syn. P. ilicicola var. tazzekensis (INED.?) --- P. tazzekensis Werner

44a (33) On bark; thallus C+ red, white to greyish, smooth to rimose-verruculose, at the margin often radiate-plicate; fertile warts numerous but scattered, 0.5- over 1 mm wide, lecanora-like rounded, with strong, raised, sometimes finely sorediate margin and usually single, pale reddish disc; ascospores about 150-300 x 50-90 µm; lecanoric acid, sometimes with lichexanthone; SW Europe, occasionally extending to the Baltic --- 1/2/4/5/P. velata (Turner) Nyl.
44b On rock --- 45

45a Thallus C+ pink or red, KC+ pink or red; lichexanthone, lecanoric acid; thallus whitish, thickish, more or less covered by semiglobose, more or less coarsely warty fertile warts; discs reddish, to 0.5 mm wide; ascospores about 200-270 x 70-85 µm; France, collected once, unusual form of P. velata?; acc. to Boqueras (2000) in Spain --- 2/5/P. conglobata (Ach.) Th. Fr.
45b Thallus C-; arctic species with pruinose discs on more or less calcareous substrate --- 46

46a Thallus J+ clearly blue, thin, whitish-greyish, areolate, with 1-1.5 mm wide, raised fertile warts bearing 1-2 blackish, 0.3-0.5 mm wide discs; ascospores about 135-240 x 40-90 µm; protocetraric acid; Nowaja Semlja; = P. cribellata Branth? --- 5/P. solitaria H.Magn. (non Darb.) NOM. ILLEG.
46b Thallus J- or medulla weakly J+ violet; thallus chalky-whitish, at border almost lobed, rather thick; fertile warts in the centre dense, with 1-3 black, more or less white-pruinose, rounded-deformed discs and thick margin; ascospores about 140 x 50 µm; no substances; Lapland, on limestone --- 1/5/P. tornensis H.Magn.

47a (8) Fertile warts strongly widened at base, not sharply delimited from the thallus, usually flat; soralia absent; thallus K- to K+ pale yellow, rarely more strongly yellow, sometimes endophloeiodic; on bark --- 48
47b Fertile warts sharply delimited, usually distinctly contracted at base or areole-like; thallus K-, K+ yellow or K+ yellow turning red, always epiphloeodic when on bark; on soil, bark or rock --- 55

48a Ascospores 8/ascus --- 49
48b Ascospores usually 4-5(2-8)/ascus; thallus thin, at least initially endophloeodic, whitish to greenish grey; coronaton, usually with stictic, norstictic acids, indet. depsids; fertile warts 1-2 mm wide, slightly convex-flattened, often dense, basally constricted or nodulose, usually with 1- few ostioles; ostioles usually greyish or brownish to blackish, but sometimes widened, flesh-coloured, with pale to brownish epithecium; ascospores about 70-100 x 25-40 µm; on smooth bark of forest trees, mainly Fagus, widespread in the deciduous forest zone, variable, often with the hymenia eaten away; syn. P. leioplaca (Ach.) DC. --- 1/3/4/10/P. leucostoma (Bernh.) A.Massal.
48c Ascospores 2/ascus --- 51

49a Thallus endophloeodic to weakly epiphloeodic; stictic acid present; in N Europe, the Alps, Carpathians, Vosges --- 49'
49b Thallus clearly epiphloeodic; stictic acid absent (unknown in 50b); in southern Europe --- 50

49'a Epithecium blackish, K+ violet like dark marginal rim; ascospores about 20-40 x 12-20 µm; thallus thin, endophloeodic, whitish-greyish; coronaton, stictic sometimes with tr. norstictic and/or constictic acids, sometimes subst. mH; fertile warts to 1 mm wide, at base widened to contracted, usually with 1-5 ostioles; on bark and wood of deciduous trees and Juniperus, mainly near the soil, in N Europe, the Alps, Carpathians, Vosges --- 1/2/5/P. sommerfeltii Flörke
49'b Epithecium almost colourless to brownish; ascospores about 30-70 x 20-30 µm with weakly punctuated wall; thallus thin, endophloeodic to weakly epiphloeodic, more or less grey-greenish; coronaton, stictic, tr. norstictic, constictic acids; fertile warts to 2.6 mm wide, with 1-3(-8) pale ostioles; on smooth bark of young trees, e.g. Alnus, in N Europe and at lower elevations in the Central European mountains till Dalmatia; syn. P. leioplaca v. octospora Nyl. --- 1/2/5/10/P. alpina Hepp

50a Ascospores about 50-60 x 25-30 µm, (4-)8/ ascus, with smooth walls; 1-2 pale. punctiform ostioles/wart; coronaton, 2'-O-methylperlatolic, confluentic acids; in Caloplacetum pollinii in Spain; also in Greece --- 3/10/P. sp. 1 (Giralt 1996) = P. werneriana Boqueras
50b Ascospores 90-95 x 33-36 µm; thallus thin, smooth, greyish white, K+ yellowish, C-, KC+ yellowish; fertile warts depressed-subglobose, not constricted at base, 0.7-0.7 mm wide; ostioles mostly single, brown-black, immersed, 0.2-0.3 mm wide; on Erica on Teneriffe --- P. teguestensis Erichsen
50c See also P. cypriaca Erichs. 37c, P. debazaci R. G. Werner 37d, and P. lapieana Bouly de Lesd. 40b, poorly-known Mediterranean corticolous taxa.

51a Ostioles pale to pinkish --- 52
51b Ostioles blackish --- 53

52a Thallus thin, UV+ orange; fertile warts rounded to irregular, rimose, flat; artothelin, granulosin, gyrophoric, lecanoric acid; ostioles 1-3/wart, flat, 0.3-0.4 mm wide, pale, C+ pinkish red; ascospores 80-110 x 28-50 µm, with transversally striate walls; Portugal, Baleares Isl. --- 5/10/P. dispar J.Steiner
52b As a, ostioles C-; thiophaninic, stictic, and traces of norstictic, constictic acids, 0-methylmonochlorlichexanthone; ostioles with colourless epithecium, to 0.5 mm wide, usually single or with few together, in to 1.5 mm wide fertile warts; ascospores about (50-)70-110(-170) x 25-60 µm with transversely striated walls; on bark in the Mediterranean; syn. P. maximiliana Klem. --- 2/3/5/10/P. heterochroa (Müll.Arg.) Erichsen

53a Fertile warts slightly convex, at base widened to clearly delimited; ascospores about 100-220 x 40-75 µm, with slightly plicate walls; mainly on Fagus and Carpinus in Central Europe widespread but infrequent; syn. P. leioterella Erichsen, P. communis v. leiotera Nyl., P. colliculosa Körb. --- see P. pertusa 79b
53b Fertile warts slightly convex, at base scarcely widened, c. 0.5 mm wide; coronaton, tr. confuentic, 2'-O-methylperlatolic acids; ostioles usually single, pruinose; epithecium granulose-greyish; ascospores 65-95 x 25-27 µm; on Quercus in Israel --- 5/P. carmelii Reichert & Galun
53c Fertile warts flat, regularly becoming apothecium-like with widened discs --- 54

54a Discs remaining punctiform or soon deformed, with whitish, irregular, about 0.5 mm wide margin, 1-8/wart; thallus thin, grey-greenish; epithecium blackish, K+ red-violet; ascospores about 60-130 x 20-40 µm, wall finely striate; thallus KC+ yellow to yellow-reddish; stictic acid, 2-chloro-6-O-methylnorlichexanthone, sometimes with (traces of) constictic, norstictic acids; on smooth bark of young deciduous trees, especially Fagus, Mediterranean-Atlantic till western Central Europe (syn. P. exalbescens Nyl.) --- 2/3/5/10/P. pustulata (Ach.) Dufour
54b Discs remaining punctiform, 1/wart; thallus thin, grey, often with yellowish tinge; epithecium dark green or blackish, K-; ascospores 70-95 x 25-35 mu, wall transversely striate; thallus KC+ orange-red; thiophaninic and norstictic acids; on smooth bark, Spain --- 10/P. luteola Boqueras

55a (47) Thallus K+ yellow->fast red (norstictic acid) --- 56
55b Thallus K+ yellow (usually stictic or thamnolic acid) --- 61
55c Thallus K- (no norstictic, stictic, thamnolic acid) --- 81

56a On bark and wood --- 57
56b On rock --- 58

57a Thallus with irregular, sorediate outbursts, without isidia, rimose-warted, whitish; thallus P+ strongly yellow; fertile warts scarce, always cushion-like accumulated, with depressed ostiole; ascospores 1-2/ascus, 110-195 x 34-55 µm; particularly on Fagus, Yugoslavia --- 8/P. servitiana Erichsen
57b Thallus isidiate, more or less grey, often grey-greenish; isidia granular to elongate-coralloid, about 0.1-0.4 mm thick, often in cushion-like accumulations, in places becoming sorediate; fertile warts rare, usually cushion-like accumulated; ascospores (1-)2(-4)/ascus, about 100-200 x 30-60 µm; thallus P+ yellow, sorediate spots P+ orange; norstictic acid; on bark of old, free-standing trees in deciduous forest zone of W and Central Europe, widespread and common, very variable; syn. P. phymatodes (Ach.) Nyl., form of shady places with longer isidia; P. polycarpiza Choisy et Werner --- 1/2/4/5/P. coccodes (Ach.) Nyl.

58a Isidia absent --- 59
58b Isidia present, granular to coralloid --- 60

59a Thallus deeply rimose-areolate, rather thick, brownish white; isidia absent; thallus C-, P-; norstictic acid; fruit-bearing areoles to over 3 mm wide, smooth, with many congested, to about 1 mm thick, each with 1-8, blackish ostioles; ascospores 2/ascus, about 150-250 µm long, often poorly developed; on non-calcareous rock, e.g., serpentine, Mediterranean-Atlantic --- 2/5/P. apennina Bagl.
59b Thallus yellowish, rather thick, UV+ orange, K+ yellow turning red, KC+ orange, P+ range, warty-rimose, cartilaginous; thiophaninic and norstictic acid major; fertile warts 1-2 mm wide, semiglobose, with more or less depressed tip containing usually several black, non-pruinose ostioles; ascospores 8/ascus, 85-110 x 40-65 µm, thick-walled; on sandstone on the Baleares (type only); close to P. rupicola but with different chemistry --- P. huneckiana Feige & Lumbsch

60a Isidia cushion-like, greyish to pale brownish, without dark tip; occasionally on rock (when isidia finely granular, 0.1-0.4 mm wide; thallus with plenty punctiform sorediate outbursts; on granite in N Germany: v. petraea Erichsen) --- see P. coccodes 57b
60b Isidia with thickened, blackish tip, scattered, fragile and leaving crater-like scars, 0.5-1 mm thick, usually short granular, more rarely elongated; thallus rimose-areolated, brownish grey; areoles about 1-3 mm wide, warty to nodulose; medulla P+ orange, K+ yellow-red, KC+ yellow-red, C-, UV-; norstictic acid; apothecia rare, with 2-7 punctiform, grey-black ostioles in 1-3 mm wide, more or less dense, semiglobose fertile warts; ascospores 2/ascus, about 125-200 x 50-80 µm; on non-calcareous rock from Scandinavia through Central and Western Europe to the Mediterranean, very scattered; syn. P. ceuthocarpoides Zahlbr., P. microsticta (Sm.) Erichsen, P. concreta Nyl. --- 1/4/5/P. pseudocorallina (Sw.) Arnold

61a (55) Isidia present; thallus often sterile --- 62
61b Isidia absent; thallus usually fertile --- 65

62a On rock --- 63
62b On bark --- 64

63a Thallus grey, KC- or + pale yellowish; medulla J-; thallus always fertile, thickish, rimose-areolated, with usually numerous, small, 0.2-0.5 mm high and 0.2 mm wide isidia; coronaton, stictic (+ tr. norstictic, constictic) acids; fertile warts semiglobose, isidiate, with 1-6 ostioles; ascospores 2/ascus, about 170-230 x 60-80 µm; Western Europe, occasionally to Saxony; syn. P. chionea; = P. pertusa? --- 2/5/7/P. areolata (Ach.) A.Massal.
63b Thallus yellowish, KC+ orange, UV+ orange, with usually scattered, elongated, to 2 mm long and 0.3-0.5 mm wide, usually simple papillae; preferably on steep rock faces in Mediterranean; for further details see P. rupicola (68a) --- 2/P. rupicola (Fr.) Harm. v. coralloidea (Anzi) Croz.

64a Thallus P+ ochraceous, K+ orange, greyish green to pale- or yellowish grey, more or less densely covered by granular to elongate and coralloid, about 0.05 mm thick isidia, additionally with sorediate outbursts; coronaton, stictic sometimes with tr. norstictic and/or constictic acids; fertile warts semiglobose, more or less isidiate, usually in groups, with usually 1-4 ostioles; ascospores usually 4/ascus, about 90-160 x 45-70 µm; on bark mainly of broad-leaved, wayside trees, in temperate Europe widespread but scattered, rarely fruiting; syn. P. isidiifera Erichsen, shade form with elongate isidia --- 1/2/4/5/P. coronata (Ach.) Th.Fr.
64b Thallus P+ yellow, K+ yellow, more or less greyish, with scattered, button-like, to 0.1 mm thick isidia; thamnolic acid; species rarely on bark in southern Central Europe --- 7/see P. corallina 17a

65a (61) On rock --- 66
65b On bark --- 72

66a Thallus composed of scattered, small, semiglobose warts, brownish grey to pale reddish, P-; indet. substances; sterile; Tatra; uncertain taxon probably no Pertusaria --- 5/P. scepusiensis (Gyeln.) Erichsen
66b Thallus continuous --- 67

67a Ascospores 8/ascus --- 68
67b Ascospores 2/ascus --- 69

68a Thallus yellowish, UV+ orange, K+ orange-yellow, KC+ orange, P+ ochraceous, warty-rimose, cartilaginous; thiophaninic, stictic acid, sometimes trace norstictic; fertile warts to 2 mm wide, semiglobose, with more or less depressed tip containing usually several ostioles; epithecium K+ red violet and C+ red violet; ascospores about 70-100 x 30-50 µm, thick-walled; on silicate in Mediterranean widespread, extending into the southern Alps and England; cf. P. huneckiana with norstictic instead of stictic acid. --- 2/5/P. rupicola (Fr.) Harm.
68b Thallus grey, dusty; fertile warts small, 0.5-0.7 mm wide, densely covering the thallus, semiglobose, usually with 3-6, often deformed ostioles which may fuse into discs; stictic acid; ascospores about 25-45 x 15-25 µm; on granite in Silesia; syn. P. polycarpa Eitner --- 5/P. eitneriana Erichsen

69a Thallus yellowish, KC+ orange, UV+ deep orange-red, rimose-areolate; thiophaninic, stictic acids major; fertile warts slightly enlarged but scarcely thicker than sterile areoles, with several flesh-coloured (P. gallica?) or dark ostioles; ascospores about 75-140 x 35-60 µm, with transverse striation; on non-calcareous rock in western Europe; syn. P. gallica B. de Lesd. --- 5/8/P. pluripuncta Nyl.
69b Thallus whitish grey, KC-; coronaton, stictic acid (as far as known) --- 70

70a Fertile warts applanate; thallus grey; sterile areoles till 1-1.5 mm wide; fertile areoles to 2.5 mm wide, with 1-2(-4) apothecia, often congested in nodulose groups; coronaton, stictic acid; ascospores about 100-170 x 30-60 µm; northern Ural --- 5/P. globulata Oxner & A.M.Volkova
70b Fertile warts semiglobose; thallus yellowish --- 71

71a Medulla J-; thallus more or less grey, cartilaginous, usually more or less rimose-areolate; thallus K+ yellow, KC+ yellow, P+ orange-reddish; coronaton, stictic acid and accessories; fertile warts scattered to dense, about 1-1.5 mm wide, with 1 to few, punctiform ostioles; ascospores about 180-230 x 70-85 µm; on non-calcareous rock throughout Europe, scattered; syn.: P. pallidoflava Erichsen; probably saxicolous form of P. pertusa --- P. rupestris (DC.) Schaer.
71b Medulla J+ blue; like P. rupestris; fertile warts to 2 mm wide, with 1-5 ostioles; ascospores about 170-215 x 58-80 µm; on granite in Corsica; = P. rupestris? --- 8/P. subrupestris Zschacke

72a (65) Ascospores 8/ascus --- 73
72b Ascospores c. 4/ascus --- 78
72c Ascospores 2/ascus --- 79
72d Ascospores 1/ascus, with pitted walls, 130-250 x 60-70 µm; thallus whitish, thin, with scattered to dense, basally strongly constricted, to 0.7 mm wide fertile warts with 1-7 ostioles; thallus K+ pale yellowish, C-, P-; ascospores J+ violet; on Salix in Norway --- 1/P. porospora Norm.

73a Fertile warts with swollen margin surrounding one or several depressed, widened, confluent ostioles; Mediterranean-oceanic --- 74
73b Fertile warts with not-depressed tip; ostioles persistently punctiform --- 75

74a Thallus yellowish grey to grey or strongly yellow, C-, P-, usually largely covered by numerous, to 2 mm wide, often deformed-plicate fertile warts containing usually 1-4 ostioles; ascospores usually 8/ascus, about 60-110 x 30-50 µm; on smooth bark in Mediterranean and Atlantic Europe, northward till S. Finland, lacking in the Alps; syn. P. wulfenii DC., P. sublecanorodes Werner --- P. hymenea (Ach.) Schaer.
74b Thallus yellowish white, C+ yellow, P+ blue-grey, long endophloeiodic, later powdery, warty; fertile warts semiglobose, to 2 mm wide; ascospores about 90-120 x 40-55 µm; thiophaninic, sometimes with gyrophoric acids; Dalmatia, S. France --- 5/P. cyparissi Körb.

75a Thallus C-; coronaton present --- 76
75b Thallus C+ orange; thiophaninic acid present --- 77

76a Thallus grey, epiphloeodic, smooth to rugulose; fertile warts numerous, usually scattered, semiglobose, to 2 mm wide, at base distinctly constricted, usually with 3-6 ostioles; ascospores mostly 8/ascus, about 30-60 x 15-30 µm; thallus K+ yellowish to brownish, C-, P-; coronaton, stictic (+ tr. norstictic) acids; mountain forest of alpide mountains and southern Europe --- 2/5/P. constricta Erichsen
76b Thallus whitish, long endophloeodic; fertile warts to 1 mm wide, usually with single apothecium, with more or less widely blackened tip; ascospores 25-40 x 15-20 µm; thallus K+ pale yellow, C-, P-; on bark and wood usually of conifers in N Europe and the Alps. --- P. sommerfeltii Flörke v. melanostoma (Wahlenb.) Th.Fr.
See also P. alpina (49'b)

77a Thallus yellowish, epiphloeodic, smooth to rugulose; fertile warts numerous, usually scattered, semiglobose, 0.5-1(-1.5) mm wide, at base hardly constricted, with a single, yellowish to yellow, indistinct ostiole; ascospores 6-8/ascus, about 50-70 x 30 mu, irregularly uniseriate, ellipsoid, smooth-walled; thallus K+ yellowish, C-; thiophaninic, stictic acids major; Morocco --- P. leioplacella Nyl.
77b Thallus yellowish, epiphloeodic, smooth to rugulose; fertile warts numerous, usually scattered, semiglobose, smaller than in P. leioplacella, at base hardly constricted, with a single(-2), yellowish to yellow, indistinct ostiole; ascospores 6-8/ascus, about 30-70 x 20-30 µm, uni- or biseriate, ellipsoid, smooth-walled; thallus K+ yellowish, C-; thiophaninic acid alone; SW France, Spain (Boqueras 2000) --- 5/P. plombii B. de Lesd.

78a (72) Thallus thin, brownish, with very small, nodose, about 0.4 mm wide, dense fertile warts with to 6 ostioles; ascospores 1-6/ascus, about 60-90 x 30-40 µm; thallus K+ yellowish, C-, P-; coronaton, stictic (+ tr. norstictic, constictic) acids; on Carpinus in Silesia --- 5/P. caesioumbrina Eitner
78b Thallus grey, with larger fertile warts; ascospores usually 4/ascus --- see P. leucostoma 48b

79a (72) Thallus more or less yellowish-greyish, long endophloeodic, thin; thiophaninic, stictic, sometimes traces norstictic, constictic acids; fertile warts flattened, basally distinctly constricted, about 1-1.5 mm wide, with usually 1-4, ochraceous, waxy ostioles; ascospores about 100-145 x 40-60 µm, with smooth wall; on deciduous trees in the Mediterranean, very rare: Dalmatia, Portugal, Azores --- 5/P. ficorum Zahlbr.
79b When spores 2/ascus and striate, see see P. heterochroa 52b
79c Thallus greyish, verruculose to rimose; fertile warts scattered to dense, to about 2 mm wide, semiglobose, basally more or less strongly constricted, of irregular shape, with usually several to many ostioles; ascospores about 145-230 x 40-80 µm, with zoned or grooved wall; thallus P+ orange-red, K+ yellow, C-, KC+ yellow, UV+ pale orange; coronaton, stictic acid, sometimes norstictic, constictic acids, subst. mH; on bark mainly of deciduous trees, in central Europe very widespread and polymorphic, in the Alps up to the subalpine zone. --- (P. pertusa) 80

80a Thallus whitish to yellow-whitish; fertile warts low and wide with many conspicuous, blackish ostioles; Mediterranean; syn. P. gattefossei Choisy on limestone in Morocco?; syn. P. oleae Zschacke from Corsica? (medulla J+ blue; epithecium K+ violet) --- 1/2/5/P. pertusa (L.) Tuck. v. meridionalis Zahlbr.
80b Thallus more or less grey; fertile warts with usually less ostioles; widespread; syn. P. chioneoides Erichsen --- v. pertusa

81a (55) Thallus C- --- 82
81b Thallus C+ red --- 89

82a On rock --- 83
82b On bark --- 85

83a Thallus thin, whitish to dirty reddish, without papillae but with punctiform, to 0.3 mm wide soralia; alectoronic acid, indet. substances; fertile warts scarce, rounded, about 1-2.5 mm wide, to 0.8 mm high with usually many pale reddish, finally slightly widened ostioles; ascospores 8/ascus, about 30-50 x 15-35 µm, thin-walled; on steep faces in Finmark --- Ochrolechia rhodoleuca (Th.Fr.) Brodo
83b Thallus papillate-isidiate --- 84

84a Medulla KC+ violet, with bitter taste; thallus grey, densely covered by simple to branched, to about 5 mm high, 0.5-1 mm thick papillae; fertile warts stalked like papillae, finally irregularly nodular, to about 3.5 mm wide, with usually several, finally widened ostioles confluent in a disc; ascospores 1/ascus, about 180-300 x 70-100 µm; medulla and ostioles P+ red, KC+ violet; picrolichenic and protocetraric acids; SW Europe, Wales, W Norway; probably heterogeneous --- 1/2/4/5/P. melanochlora (DC.) Nyl.
84b Medulla KC- or + pale yellow, without bitter taste, J+ reddish; papillae usually not branched; thallus always sterile, rimose-areolate, with scattered, strong, short-cylindrical, to 1.5 mm high and about 0.5 mm wide papillae; fatty lH; on acid silicates in the central Alps and Black Forest; syn. P. isidioides (Schaer.) Arnold --- 2/5/P. schaereri Hafellner

85a Thallus more or less endophloeodic, whitish --- 86
85b Thallus clearly epiphloeodic --- 87

86a Ostioles pale to yellowish, deeply impressed; fertile warts about 0.6-0.8 mm wide, semiglobose, basally strongly constricted, with single ostioles; asci ventricose-bacillar; ascospores 4-?/ascus, about 50-70 x 20-40 µm; on Alnus in Finland --- P. poriniza Nyl.
86b Ostioles black; coronaton, stictic acid; fertile warts to 1 mm wide, at base widened to contracted, usually with 1-4 ostioles; ascospores 8/ascus, about 20-40 x 12-20 µm --- see P. sommerfeltii 49'a

87a Fertile warts with yellowish tip, on whitish thallus, to 1.5 mm wide, flattened semiglobose, basally strongly constricted; alectoronic (sometimes absent?), lichesterinic acids; ostioles yellowish-brownish; ostioles usually in groups of 1-3; ascospores 4/ascus, about 50-80 x 30-40 µm; on bark mainly of Juniperus twigs and on rock outcrops, in subarctic northern Fennoskandia, Iceland, Faroes, Scotland, Alps?; syn. Ochrolechia xanthostoma (Sommerf.) K.Schmitz & Lumbsch --- 1/4/5/P. xanthostoma (Sommerf.) Fr.
87b Fertile wart tips concolorous with thallus; ostioles blackish; thallus grey, strong; in deciduous forest zone --- 88

88a Ascospores 2/ascus --- see P. pertusa 79b and P. carmeli 53b
88b Ascospores 4/ascus --- see P. leioplaca 48b
88c Ascospores 6/ascus, about 60-90 x 30-40 µm; thallus grey; fertile warts scattered, basally strongly constricted, with 1-several ostioles; coronaton, sometimes with stictic (+ tr. norstictic) acid; on Populus in Finland --- 5/P. raesaenenii Erichsen
88d Ascospores 8/ascus --- see P. hymenea 74a, P. cypriaca 37c, P. debazaci 37d, P. werneriana 50a, P. teguestensis 50b and P. plombii 77b

89a (81) On bark --- see Ochrolechia subviridis 99b
89b On rock --- see P. kasandjefii 100a

90a (2) Medulla and, if present, soralia C+ pink or red and/or KC+ pink, red or violet-red --- 91
90b Medulla and, if present, soralia C-, KC- or C and/or KC+ yellow to orange, not pink-red --- 109

91a Medulla and, if present, soralia C+ pale red to red, KC+ red, P- or P+ yellowish; thallus without bitter taste (gyrophoric or lecanoric acid usually present) --- 92
91b Medulla and, if present, soralia C-, KC+ violet-red, P- or P+ orange to red; thallus with bitter taste (picrolichenic or (fumar)protocetraric acid present) --- 101

92a Thallus sorediate; on rock or bark --- 93
92b Thallus not sorediate; on rock --- 100

93a On rock --- 94
93b On bark --- 95

94a Thallus rimose-areolated, almost smooth, rather thick, at border radiate-rugulose, the areoles about 0.3-0.8 mm wide; lecanoric, variolaric acids; soralia rounded, coarse-grained; fertile warts usually with single, brownish disc, initially white-pruinose; ascospores 1/ascus, about 180-240 x 60-100 µm; on non-calcareous or weakly calcareous rock, scattered throughout Europe, locally frequent; syn.: Ochrolechia lactea (L.) Hafellner & Matzer --- 1/2/4/5/Pertusaria lactea (L.) Arnold
94b Thallus rather thick, not rimose but swollen-warty, between the warts coarsely sorediate; gyrophoric acid; S France; syn. P. tumidula Erichsen --- Ochrolechia crozalsiana Clauz. & Vezda

95a Thallus with delimited, rounded soralia, whitish grey to pale grey --- 96
95b Thallus without rounded soralia --- 99

96a Thallus densely coarse-warty, not radially rugulose; soralia mostly on the tip of basally constricted warts; gyrophoric and variolaric acid; disc dark, pruinose; Yugoslavia, S. France, Spain; syn. Pertusaria dalmatica Erichsen --- 2/5/14/O. dalmatica (Erichsen) Boqueras
96b Thallus not coarse-warty; soralia appressed --- 97

97a Thallus with distinct, zoned, silverish-white, radially rugulose border, in the center not areolated, with 1-1.5 mm wide, more or less strongly convex soralia; cortex K-; lecanoric acid dominant, with or without variolaric acid; on bark of deciduous trees in light forest or free-standing, widespread in central Europe but common only in suboceanic areas --- 1/2/4/5/P. hemisphaerica (Flörke) Erichsen
97b Thallus without distinct, zoned border; gyrophoric acid dominant substance, usually with a trace of lecanoric acid --- 98

98a Thallus UV+ yellow, not cartilagineous; lichexanthone, gyrophoric acid; soralia about 0.5-1 mm wide; cortex K+ yellowish; East Central Europe, Eastern Europe; syn. P. arborea Krey, P. myriosora Erichs. --- 5/Ochrolechia arborea (Krey) Almb.
98b Thallus UV- or + whitish, thin or rather thick, cartilaginous, pale brownish grey, hardly fissured, irregularly warted; gyrophoric, variolaric, tr. lecanoric acids; soralia dense, rounded, usually flat, or somewhat concave, farinose, whitish, 0.4-0.8 mm wide, sometimes confluent; fertile warts rare, scattered, subhemispherical with constricted base, with slightly depressed tip, white-sorediose, 0.8-1.2 mm wide; ostiole single, initially punctiform, later to 0.6 mm wide, flesh-coloured; ascospores unknown; on Pinus in Cyprus; probably belonging to Ochrolechia --- 5/P. pityreocarpa Erichsen
98c Thallus UV- or + whitish, thin or rather thick, cartilaginous, whitish grey, hardly fissured, irregularly warted; gyrophoric, tr. lecanoric acids; soralia dense, rounded, usually flat, or somewhat concave, farinose to granulose, whitish, 0.4-0.8 mm wide, sometimes confluent; fertile warts rare, scattered, subhemispherical with constricted base, with slightly depressed tip, white-sorediose, 0.8-1.2 mm wide; disc to 0.6 mm wide, flesh-coloured; widespread, common and variable --- 5/O. androgyna (Hoffm.) Arnold

99a (95) Thallus rather thick, finely warty, uneven, more or less dirty grey, with initially punctiform, later confluent soralia; C+ reddish; gyrophoric, tr. lecanoric acids; on bark of roadside trees, in northern Central Europe and southern Sweden, probably not widely distributed; syn. P. sordidogrisea Erichs. --- 5/Ochrolechia sordidogrisea (Erichsen) Schreiner & Hafellner
99b Thallus thin, grey to greenish grey, largely fine-grainedly isidiate to sorediate; on bark in suboceanic Europe; syn. P. inaequalis Erichs. --- Ochrolechia subviridis (Høeg) Erichsen

100a (92) Thallus whitish rimose-areolated; thallus warts 0.7-1.4 mm wide; lecanoric, variolaric acids; on volcanic rock in Bulgaria (perhaps in Ochrolechia?) --- 5/P. kasandjeffii Szatala
100b Thallus pale grey, not rimose-areolated; thallus warts 0.5-0.7 mm wide or confluent; gyrophoric, tr. lecanoric acids; on lava on Jan Mayen (perhaps in Ochrolechia?) --- 5/P. lavicola Erichs.

101a (91) Thallus with strong papillae or isidia, not sorediate, regularly fruiting --- 102
101b Thallus without distinct papillae, sorediate, rarely fruiting --- 103

102a On rock in western Europe --- see P. melanochlora 84a
102b On bark in N and Central Europe, Mediterranean --- see P. slesvicensis 27a

103a On rock (see also 118) --- 104
103b On bark --- 105

104a Soralia numerous, high-vaulted, dense, about 1-2 mm wide, almost covering the rimose-folded, very bitter thallus, not confluent; picrolichenic acid, sometimes with protocetraric acid; mainly on sandstone in central Europe; syn.? 5/P. caucasica Erichs. --- P. amara var. flotowiana (Flörke) Erichsen
104b As P. amara, but with picrolichenic and norstictic acids; thallus K+ yellow turning red; Spain and Canary Islands --- 5/P. teneriffensis Vain.

105a Thallus with coarse, to 4 mm wide, sorediate warts, which develop into soralia with lacerate-sorediate thalline margin; soralium discs KC+ pale reddish, P+ orange-red; picrolichenic, protocetraric acids; on bark in Yugoslavia; syn. P. amara var. szatalai (Erichsen) Clauzade & Cl.Roux --- 5/P. szatalai Erichsen
105b Sorediate warts smaller --- 106

106a Thallus thin, whitish, with irregular to irregularly rounded, flat to concave soralia; thallus strongly bitter, KC+ pale yellow becoming pale brownish red; Eastern Prussia, on Tilia --- P. pseudophlyctis Erichsen
106b Thallus rather thick, more or less densely covered with rounded to punctiform soralia, grey, soralia white; soralia KC+ violet-reddish, P+ red; apothecia very rare, in soralium-like fertile warts; ascospores 1/ascus, about 140-230 x 50-70 µm; picrolichenic +/- protocetraric acids; on bark of various deciduous and conifer trees throughout Europe, except the Arctic and the alpine zone --- (P. amara) 107

107a Picrolichenic acid present, fumarprotocetraric acid absent, protocetraric acid sometimes present; thallus usually P- --- 108
107b Picrolichenic acid absent, fumarprotocetraric acid present, with traces of protocetraric and succinprotocetraric acids; thallus P+ orange-red (if thallus largely hypophloeiodic and succinprotocetarric acid absent, see 36a P. pupillaris) Soralia mostly delimited and rounded, convex or rarely excavate, up to 1.5(-3) mm wide, occasionally fused; thallus grey, rather thin, continuous; soredia coarse, more or less fused; apothecia rare, developing in the soralia, disciform, monocarpic, with pale pink disc to 0.7 mm diam.; spores 6/ascus, 18-20 x 10-14 µm; on old Pinus in Scotland, more widespread on smooth, acid bark in Scandinavia --- 4/P. borealis Erichsen

108a Soralia about 2 mm wide, rounded, usually convex to globose, at age often concave; the common taxon --- 1/2/3/5/P. amara (Ach.) Nyl. v. amara
108b Soralia punctiform, small, on the tips of fine papillae or warts, densely covering the thallus except the outer border; mainly on roadside trees, in central Europe not rare; syn. P. pulvinata Erichsen --- 2/v. pulvinata (Erichsen) Almb.

109a (90) Cortex and/or mark K+ yellow turning red (norstictic acid) --- 110
109b Thallus not K+ red (no norstictic acid) --- 117

110a On bark --- 111
110b On rock --- 112

111a Thallus greyish, with granular to cylindrical isidia and often also with sorediate outbursts --- see P. coccodes 57b
111b Thallus whitish, without isidia --- see P. servitiana 57a

112a Thallus not areolated, dark grey to olive-greenish, hardly rimose, with numerous irregular, rounded, 0.2-0.3 mm wide, grey-whitish to greenish soralia; Holstein; = P. excludens? --- 5/7/P. inopinata Erichsen
112b Thallus rimose-areolated, whitish grey, turning brownish in the herbarium --- 113

113a Thallus with scattered, granular to cylindrical isidia, additionally often with soralia --- see P. coccodes 57b
113b Thallus without isidia --- 114

114a Soralia remaining rounded and becoming convex --- 115
114b Soralia spreading over the areoles and remaining flat, more or less confluent --- 116

115a Thallus rimose-areolated, greyish white to bluish grey, with numerous, rounded, 0.5-1-1.8 mm wide, slightly paler soralia, K+ yellow becoming red, KC+ yellow becoming orange, P+ orange-red in medulla and soralia, UV+ grey to yellowish; norstictic acid, with (?) or without salazinic, fatty acids, xanthone; SW Europe till Black Forest (see also Coccotrema citrescens, with diffuse cephalodia; stictic acid; close to soil; coastal Scotland, N. Ireland) --- 1/2/5/P. excludens Nyl.
115b Thallus rimose-areolated, whitish; areoles convex to wart-like with constricted base, becoming sorediate at the tips; norstictic and protocetraric acid; ascospores 2/ascus, about 80-150 x 50-80 µm; calcareous rock, Algeria --- 5/P. fdoulesiana Harm.

116a Soralia usually flat remaining discrete and well-crowded, often becoming confluent or becoming slightly convex, usually delimited, (0.2-)0.3-0.7(-0.8) mm diam.; soralia greyish, pigment K+ violet (thalloidima green) --- see P. lactescens 7b
116b Soralia usually diffuse and becoming confluent or becoming slightly convex, usually delimited, (0.2-)0.3-0.7(-0.8) mm diam.; soralia without thalloidima green. --- Phlyctis argena (Spreng.) Flot.

117a (109) On rock --- 118
117b On bark --- 130

118a Thallus isidiate or papillate, sometimes with apical soralia --- 119
118b Thallus sorediate, soralia not apical on papillae --- 122

119a Isidia present, slender, cylindrical, 0.1-0.3 mm thick, simple to branched --- 120
119b Papillae present --- 121

120a Thallus pale grey; C-, UV-; thamnolic acid --- see P. corallina 17a
120b Thallus pale yellowish grey; C+ orange, UV+ dark red; thiophaninic acid; on top of more or less calcareous, schistose boulders, Scotland, Sweden, Norway, rare --- 4/P. flavocorallina Coppins & Muhr

121a Papillae mammiform, with white soralia on top --- see P. mammosa 18a
121b Papillae semiglobose to short cylindrical, 0.5-1 mm thick, usually without soralia --- see P. stalactiza 18b

122a Thallus C+ yellowish to orange, with rounded soralia --- 123
122b Thallus C-, mostly P+ red, KC+ pink (protocetraric, fumarprotocetraric and/or succinprotocetraric acid); soralia various --- 125

123a Thallus thin, pale grey, initially radiately rimose, later rimose-areolated; soralia not dense, at first small, pale and fleck-like, becoming diffuse and contiguous; thallus weakly bitter, KC+ orange; thiophaninic, stictic, menegazziaic, tr. norstictic acids; looks like P. amara; Italy, Britain; syn. P. affinis Erichsen --- 2/4/5/P. amarescens Nyl.
123b Thallus sulphur-yellow to yellow-grey, C+ yellow, KC+ yellow, UV+ orange, more or less warty, rimose-areolated, with mostly irregularly rounded, yellowish, sometimes confluent soralia; thiophaninic acid sometimes with other xanthone or stictic acid (+ norstictic, constictic); mostly in steep faces of non- to weakly calcareous rock --- (P. flavicans) 124

124a Thallus thin, smooth, yellowish to yellow-grey or greenish grey, with small to 1 mm wide areoles and usually scattered, flat soralia; on calcareous schist and siliceous limestone in the alpine and upper alpine zone of the Alps --- 1/2/4/5/P. flavicans Lamy v. schistosa Erichsen
124b Thallus thicker, always yellowish to yellowish green, at most in shade forms grey, with irregular, often confluent soralia; widespread on non-calcareous rock in the Mediterranean, occasionally in warmer parts of Central Europe --- v. flavicans

125a On limestone or gypsum --- 126
125b On siliceous stone; always P+ red --- 127

126a On limestone; thallus thick, whitish, not areolated, at most finely rimose, with larger, 1-2 mm wide, sorediate warts and smaller, 0.4-0.6 mm wide, basally constricted, not sorediate warts; protocetraric, succinprotocetraric acids; on limestone in Tyrol --- 5/P. pseudolactea Erichsen
126a On gypsum; thallus blackish, sharply delimited; soralia small, punctiform, 0.1-0.2 mm wide, dirty greenish; medulla K+ yellow; no substances; north Germany; = Lecanora sp. --- 5/7/P. gypsicola Erichsen

127a Fumarprotocetraric acid major, protocetraric acid minor --- 128
127b Protocetraric acid major --- 129

128a Thallus grey, moderately thick, rimose-areolate, irregularly fine- to coarse-warted, with almost concolorous, coarse soralia on viz. between the warts; soralia yellowish white, 0.5-0.8 mm wide; fumarprotocetraric, tr. protocetraric acids; on granite in Rumania --- 2/5/P. erumpens Erichsen
128b Thallus grey, rather thin, areolated or not, smooth to finely warty-scabrid, with irregular, often confluent, yellowish white soralia, additionally isidiate; fumarprotocetraric, sometimes with succinprotocetraric acid major; scattered on non-calcareous boulders in temperate Europe, variable; syn. P. dealbescens Erichsen, P. dealbata Auct., P. leucosora Auct. --- P. aspergilla (Ach.) J.R.Laundon

129a Thallus areolated, whitish to ash-grey, with large, about 1-1.5 mm wide, dense soralia; protocetraric acid; syn. P. albescens (Huds.) Choisy et Wern. v. subflotowiana (Erichs.) --- 2/5/P. leucosora Nyl.
129b Thallus rimose, not areolated, with whitish, to 1.5 mm wide, coarse-granular to isidiate soralia; protocetraric acid; fertile warts common, to 0.2 mm wide, with up to 3 discs and sorediate margin; ascospores 2/ascus, about 100-150 x 50-70 µm; medulla J- or J+ bluish; W. & S. Alps --- 2/5/P. digrediens Nyl.

130a (116) Thallus fine- to coarse-isidiate, isidia not soon disintegrating into soredia, occasionally with additional rounded to irregular soralia --- 131
130b Thallus not isidiate, or with soon disintegrating, isidium-like pustules --- 132

131a Thallus sulphur-yellow to yellow-grey, UV+ orange, uniformly covered by fine, somewhat globular, about 0.5 mm wide isidia, occasionally with finely sorediate, yellowish outbursts; thallus grey at the border; thallus C+ yellow to orange, KC+ yellow to orange, UV+ bright orange; (3 strains) thiophaninic acid, without or with stictic acid, confluentic or 2'-O-methylperlatolic acids and traces; discs very rare, 2-4 together immersed in semiglobose, sorediate fertile warts; ascospores usually 8/ascus, about 60-100 x 25-40 µm; on bark of deciduous trees in oceanic or warm parts of Europe, absent from cool regions, variable; syn. P. lutescens (Hoffm.) Lamy --- 1/2/4/5/P. flavida (DC.) J.R.Laundon
131b Thallus yellowish green-grey, with scattered, more coarse, rounded to coralloid-elongate isidia, KC- --- see P. coronata 64a

132a Thallus without distinctly delimited, more or less rounded soralia, completely covered by soredia except at the border --- 133
132b Thallus with more or less distinctly delimited soralia --- 139

133a Thallus without papillae, isidia or such, but largely sorediate --- 134
133b Thallus with isidia, papillae or nodulose excrescences --- 137

134a Thallus sulphur-yellow; thallus very thin, uniformly fine-sorediate, the soredia about 0.2 mm wide, sulphur yellow, KC+ yellow to brownish, C-, P-; atranorin, indet. substances; central Europe; not in Pertusaria, aff. Lecanora? --- 5/P. pulvureo-sulphurata Harm.
134b Thallus not sulphur-yellow --- 135

135a Thallus P- or P+ orange to red --- 136
135b Thallus P+ citron yellow, thin, grey-whitish, finely rimose (to areolate), warty; cortex from the beginning dissolved; surface finally confluently sorediate, soralia with pale brownish tinge; on Acer, East Prussia --- P. dissoluta Erichsen

136a Thallus rather thick, delimited, at the border with a few distinct soralia, in the center covered by brownish grey soredia 0.08-0.12 mm large; apothecia very rare, in semiglobose, sorediate warts; widespread on roadside trees; syn. P. leprarioides Auct. --- Ochrolechia turneri (Sm.) Hasselr.
136b Thallus yellow- to grey-green, often shelf-like rimose-areolated, the areoles uniformly sorediate with about 40-70 µm thick soredia, K+ yellow, P+ yellow to red, C-; fumarprotocetraric acid; on coniferous trees, with boreal-montane distribution; syn. P. miniescens Erichsen --- 5/Catillaria pulverea (Borr.) Lettau

137a Thallus thickish, whitish grey, with fine-grained, dense, whitish papillae which may become sorediate; transgressing into typical variety --- 2/P. albescens (Huds.) M.Choisy v. corallina Zahlbr.
137b Like P. albescens var. corallina, with different set of fatty acids iH (similar to P. panyrga); endemic in SW Ireland --- 4/P. polythecia (Tayl.) Erichsen
137c Thallus with thicker, basally constricted excrescences --- 138

138a Thallus whitish, with 0.5-1 mm wide, semiglobose, in part sorediate, scattered or dense warts; soralia whitish to greenish grey; on free-standing trees in central and southern Europe probably widespread; syn. P. jurana Erichsen --- see P. albescens 141b
138b Thallus large, with more or less globose, to 4 mm high and 5 mm wide, apically sorediate, nodulose excrescences; fatty acid bH; rather frequently fruiting; fertile warts soralium-like; ascospores 1/ascus, about 140-250 x 50-85 mm; on old Fagus usually in larger forests in central Europe; syn. P. albescens f. tuberculata (Erichsen). --- 5/7/P. tuberculata (Erichs.) Erichs

139a (132) Thallus or soralia P+ yellow to red or blue-grey --- 140
139b Thallus and soralia P- --- 141

140a Thallus yellowish grey, in the center densely covered with irregularly rounded, to 1 mm wide, yellowish soralia, towards the border radiately rimose and often with elongate soralia along the fissures; thallus K+ yellow, soralia K+ orange, P+ yellow to red; on Fagus in the Carpathians --- P. obtecta Erichsen
140b Thallus grey, grey-green; soralia often irregularly deformed to confluent, pale flesh-coloured white, P+ blue-grey, on ashy grey to brownish thallus; on Fagus in the Vosges (according to Hanko 1983) a synonym of Lecanora impudens, containing atranorin and an indet. trace) --- P. cinereocarneola Harm.

141a Soralia small, to about 1 mm wide, scattered; thallus weakly yellowish grey; variolaric and lichesterinic acids; on bark of old coniferous trees in boreal-montane regions, nitrophobic; syn. P. decipiens Erichs. --- Ochrolechia alboflavescens (Wulfen) Zahlbr.
141b Soralia larger, P-; thallus strong, often extensive, grey-greenish (in shade) to whitish grey; fatty (allopertusaric, dihydropertusaric) acids, traces; apothecia very rare, in soralium-like fertile warts; discs single or with several together; ascospores 1/ascus, about 170-300 x 50-115 µm; preferably in deciduous trees in light forest and gardens, common and variable; syn. P. discoidea (Pers.) Malme. --- (P. albescens) 142

142a Thallus border several times zoned; soralia to 2 mm wide, usually slightly convex; thallus often grey-greenish; mainly in light forest; not sharply delimited from typical variety --- 1/2/3/4/5/P. albescens (Huds.) Choisy et Werner v. globulifera (Turn.)
142b Thallus border usually not zoned; soralia usually well over 2 mm wide, to 6 mm wide, often concave and thus with distinct thalline margin; thallus greyish white; mainly in gardens and along streets --- v. albescens
142c Thallus border not zoned; thallus radially fissured, seemingly lobed; soralia scattered, rounded, concave, farinose, 0.5-2 mm wide, transient into 1.5-2 mm wide aborted fertile warts with flesh-coloured discs; Rumania, on old Fagus; = P. deschatresii Werner from Fagus on Corsica? --- P. dacica Erichsen

143a (1) Thallus without isidia or soredia, usually with apothecia --- 144
143b Thallus with isidia or soralia, usually without apothecia --- 150

144a Apothecia when fully developed with distinctly widened discs, not perithecium-like --- 145
144b Apothecia persistently perithecium-like, with punctiform discs (ostioles), usually several in each fertile wart --- 146

145a Ascospores 2/ascus; on soil over calcareous shale; thallus pale grey, continuous or somewhat cracked-areolated, 0.4-1mm thick; areoles (0.4-)0.8(-1.2) mm wide; isidia and soralia absent; surface matt, slightly tuberculate; margins not zoned; P-, K-, C-, KC-, UV-; 2'-O-methylperlatolic acid; fertile warts lecanorine, 0.6-1(-2) mm wide, more or less aggregated; discs black, somewhat immersed and warty, (0.4-)0.8(-01.4) mm wide, usually single; ascospores 2(-4)/ascus, about 50-160 x 40-60 µm, with fine concentric or radial striation; Tyrolia --- P. christae Dibben & Poelt
145b Ascospores 1/ascus, usually over 100 m long; usually over calcareous substrate; thallus whitish, warty, often largely covered by semiglobose fertile warts with to 3 mm wide, rounded, yellow- to dark brownish discs; thallus K-, P-, C+ reddish, UV+ more or less glaucous to orange; gyrophoric acid with xanthone dH or stictic (+ accessories); apothecium margin initially swollen, later reduced; ascospores about 150-over 200 x 60-100 µm; Arctic, Alps and Carpathians, widespread but scattered --- 1/2/4/5/P. bryontha (Ach.) Nyl.

146a Thallus K+ yellow->fast red (norstictic acid) --- 147
146b Thallus K+ yellow or K- (no norstictic acid) --- 149

147a Fertile warts always present; ascospores 4/ascus; epithecium K+ violet --- 148
147b Fertile warts rare; thallus P-; epithecium K- or pale violet; ascospores 2/ascus, 160-230 x 50-75 µm; thallus rather thick, cartilaginous-parchmenty, whitish, slightly glossy; norstictic acid, sometimes with xanthone dH; Arctic to Scandinavia, widespread but probably much overlooked --- 1/5/P. coriacea (Th.Fr.) Th.Fr.

148a Ascospores mostly 4/ascus, about 70-125 x 25-50 µm; thallus whitish, usually completely covered by the almost globose, about 1 mm wide, dense fertile warts, which contain usually a single, dark ostiole; thallus P+ yellow, K+ yellow-red, C-, KC+ yellow-red, UV+ glaucous; norstictic acid, sometimes with tr. stictic; mainly on calcareous soil in the Arctic and Subarctic, Sudetes, Alps, Carpathians, French Jura, usually scarce --- 1/2/5/P. glomerata (Ach.) Schaer.
148b Ascospores 8/ascus, about 60-90 x 10-50 µm; like P. glomerata, with to 0.8 mm wide fertile warts; thallus P+ slowly yellowish; norstictic acid with tr. stictic; other strain with xanthon dH and stictic acid; northern Fennoscandia --- 1/5/P. octomela (Norm.) Erichsen

149a Ascospores about 30-60 x 25-35 µm; discs at first punctiform, later widened, blackish; paraphyses simple to little branched; thallus whitish, P-, with dense, almost semiglobose fertile warts; no substances; syn. P. freyi Erichs. --- 5/Megaspora verrucosa (Ach.) Hafellner & V.Wirth
149b Ascospores about 50-90 x 25-50 µm; thallus scarce, P-, white, covered by to 0.9 mm wide, flattened globose fertile warts containing usually 1 ostiole; coronaton, tr. stictic acid?; northern Fennoscandia, Scotland, Alps; in Alps also a powdery-sorediate form --- 1/5/P. trochiscea Norm.

150a (143) Isidia present --- 151
150b Soredia present --- 153

151a Thallus K-, C-, P-, with fatty acids iH, whitish, with c. 0.6 mm wide isidia without dark tips, with dense, basally constricted, somewhat columnar, 0.8-1 mm wide fertile warts with mostly 2-3 black, 0.4-0.6 mm wide discs; ascospores about 80-165 x 40-55 µm; common and widespread in the Arctic, also in Scandinavia, Scotland; syn. P. efflorescens Vain. --- 1/4/5/P. panyrga (Ach.) A.Massal.
151b Thallus K+ yellow, P+ orange to red --- 152

152a Ascospores (6-)8/ascus, usually under 50 µm long; thallus whitish grey, with numerous, about 0.3-0.4 mm thick, 1-3 mm long, fragile, dark-tipped isidia, K+ yellow becoming rusty red, P+ yellow becoming orange, C+ pink or C-, KC+ yellow-red; fumarprotocetraric, tr protocetraric or gyrophoric acids; apothecia 1-2 mm wide, with blackish disc and strong margin; ascospores about 23-30 x 10-14 µm; on acid substrate, widely distributed and not rarely fruiting in the Arctic and Subarctic, in the Alps only in the central, non-calcareous parts and here mostly sterile, similarly in the Sudetes, Carpathians, Balkans --- 1/2/4/5/P. oculata (Dicks.) Th.Fr.
152b Ascospores 2/ascus; thallus whitish, thin, covered with erect, dense, coarse, columnar, to about 3 mm tall and about 0.5-0.6 mm thick isidia with white tips; P+ red, K+ yellowish, C-, KC- or + pink, UV-; fumarprotocetraric with or without tr. protocetraric acid, sometimes lepraric acid; apothecia usually single, immersed in the tips of isidia, with rounded, blackish, about 0.5 mm wide disc; ascospores 1/ascus, about 120-300 x 60-100 µm long; on acid substrate, sometimes on bark, in the Arctic widespread, reaching Iceland, Fennoscandia, Nowaja Semlja --- 1/4/5/P. dactylina (Ach.) Nyl.

153a Thallus pinkish, consisting of scattered to crowded granules 0.1-0.2 mm wide, apically bursting and sorediate; thallus P+ yellow-orange, K+ yellow, C+ red, KC+ red, UV-; alectorialic, barbatolic acids, sometimes xanthones; apothecia rare, to 2.5 mm wide, single in a fertile granule, with dark red to purplish black disc; epithecium red-brown, K+ paler, dissolving; ascospores 2/ascus, 22-40 x 15-20 µm; arctic-alpine, occasionally on bark --- 1/2/4/P. geminipara (Th.Fr.) C.Knight ex Brodo
153b Thallus grey to whitish grey, continuous; soredia spread over larger parts of thallus --- 154

154a Thallus to 6 mm thick, finely branched, the branches dense, entangled, interconnected, K+ yellow; branch surface warty, warts 0.4-0.6 mm wide, confluent, finally sorediate but not producing distinct soralia; gyrophoric, tr. lecanoric acids?; Tirol --- 5/P. tiroliensis Erichsen
154b Thallus scarce, different; coronaton present --- see P. trochiscea Norm. 149b

not treated:

1/5/P. degelii Erichsen: gyrophoric, tr. lecanoric acids, perhaps belonging in Ochrolechia; not in Santesson (1993)
5/P. diaxantha Nyl.: usnic acid, atranorin; Karelia (= Mycoblastus)
P. djidjelliana Flagey: Algeria, on rock; no apothecia, no isidia, no soredia, K+ pale yellow; available information insufficient for inclusion in key.
5/P. hibernica Erichsen: gyrophoric, variolaric, tr. lecanoric acids; probably belonging in Ochrolechia; not accepted by Purvis et al. (1993).
P. werneri Bertrand & Prone: Vosges, France; description not seen; not accepted by Clauzade & Roux 1985.

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