Current names - Synonyms - Habitat lists (either Current names or Synonyms) - Chemistry lists (either Current names or Synonyms) - Glossary
Key to Parmelia Ach. of Great Britain and Ireland
| 1 | Thallus green-grey, blue-grey to yellow-green, or yellow-grey, grey or yellow tone predominating . . . 2 Thallus green-brown, grey-brown, red-brown or black-brown, brown tone predominating . . . 33 | |
| 2 | 1 | Thallus green-grey to blue-grey, grey tone predominating . . . 3 Thallus yellow-green to yellow-grey, yellow tone predominating . . . 25 |
| 3 | 2 | Isidia and soralia absent; surface without white pseudocyphellae . . . 4 Isidia and/or soralia present; surface with or without white pseudocyphellae . . . 6 |
| 4 | 3 | Medulla Pd-, K-, C+ red; upper surface grey or blue-grey, not dark green when wet . . . 5 Medulla Pd+ orange, K+ red, C-, ; upper surface grey-green to brown-grey, dark oily green when wet . . . acetabulum |
| 5 | 4 | Thallus closely adpressed to substratum, lobes not overlapping at the margin; usually fertile, underside of apothecia ± densely rhizinose; cortex persistent, not peeling to expose a white medulla; rhizines simple . . . quercina Thallus ± loosely attached to substratum, lobes overlapping at the margin; apothecia vary rare, underside of apothecia not rhizinose; cortex fragile, peeling to expose a white medulla; rhizines dichotomously branched . . . taylorensis |
| 6 | 3 | Isidia present . . . 7 Soralia present . . . 13 |
| 7 | 6 | Upper surface ornamented with white pseudocyphellae, either in punctiform spots or as coarse, oval to elongate, ± raised ridges which may fuse to form a network . . . 8 Upper surface devoid of pseudocyphellae . . . 9 |
| 8 | 7 | Upper surface with oval or elongate, ± raised pseudocyphellae which fuse to form a coarse, white network; isidia cylindrical; soredia absent; medulla K+ yellow, Pd+ yellow-orange . . . saxatilis Upper surface with scattered, round pseudocyphellae; isidia globose, occasionally becoming coarsely sorediate or small- lobulate; medulla Pd-, K- . . . reddenda |
| 9 | 7 | Medulla C+ pink, red or orange-red; isidia not associated with scattered black cilia . . . 10 Medulla C-; isidia mixed with scattered, fine, black cilia . . . 12 |
| 10 | 9 | Lobes >0. 5 cm wide; cilia mostly axial; wayside trees and rocks . . . 11 Lobes <0. 5 cm wide; cilia apical and axial; ancient woodlands . . . minarum |
| 11 | 10 | Isidia pale brown to grey-brown or concolorous with thallus, cylindrical- clavate, simple or coralloid . . . tiliacea Isidia blue-black, button-like with a short stalk, simple . . . pastillifera |
| 12 | 9 | Thallus large <10 cm diam., lobes <1. 5 cm wide; isidia ± cylindrical; lower surface with wide, naked zone at the margin . . . crinita Thallus small, <3 cm diam., lobes <0. 5 cm wide; isidia ± flattened; lower surface densely rhizinose to the margin . . . horrescens |
| 13 | 6 | Upper surface with white pseudocyphellae, as punctiform spots or forming a network of coarse, ± raised lines . . . 14 Upper surface smooth, devoid of white pseudocyphellae or with a faint mosaic of minute cracks . . . 18 |
| 14 | 13 | Upper surface with small, ± punctiform, rarely comma-like, pseudocyphellae which may develop into soralia . . . 15 Upper surface with oval or elongate pseudocyphellae which frequently fuse to form a coarse, white reticulum; soralia elongate, in lines, derived from pseudocyphellae . . . 17 |
| 15 | 14 | Medulla C+ red; soredia fine, powdery, not forming folioles . . . 16 Medulla C-; soredia coarse, granular, sometimes becoming corticate and forming ± flattened folioles . . . reddenda |
| 16 | 15 | Lower surface pale brown at the centre . . . subrudecta Lower surface black at the centre . . . borreri |
| 17 | 14 | Thallus firmly attached; lobes forming rosettes, not raised at apices; soredia powdery . . . sulcata Thallus loosely attached, lobes elongate, ± pendent with raised apices; soredia ± corticate . . . submontana |
| 18 | 13 | Soralia terminal, convex and delimited at ends of incised lobes; lobes ± elongate with markedly curved sinuate-rounded axils; rhizines richly dichotomously branched; medulla C+ orange . . . 19 Soralia marginal and/or laminal, mostly ± diffuse, if at lobe ends then on upper surface and only secondarily involving the apices; lobes ± rounded with indented margins and axils; rhizines unbranched or merely forked; medulla C- or C+ red . . . 20 |
| 19 | 18 | Medulla white . . . laevigata Medulla pale yellow . . . endochlora |
| 20 | 18 | Upper surface smooth, without faint mosaic of pseudocyphellae or cracks; medulla K- or + yellow, never red . . . 21 Upper surface with faint, close network of white lines, often developing into an intricate mosaic of hair-line cracks; medulla K+ blood red . . . reticulata |
| 21 | 20 | Medulla C+ red; thallus <6 cm diam. ; lobes <5 mm wide, adpressed, without raised or wavy margins; marginal cilia absent . . . 22 Medulla C-; thalli often >10 cm diam. ; lobes 5-10 mm wide often with raised or wavy margins; marginal cilia usually present . . . 23 |
| 22 | 21 | Lobes often ± elongate, axils sinuate, ascending at margins; soredia granular, blue-black; upper surface often shiny . . . britannica Lobes rounded, often indented, axils rounded but not markedly sinuose, down-turned at margins; soredia powdery, soft, concolorous or slightly darker than thallus; upper surface often matt . . . revoluta |
| 23 | 21 | Medulla and soralia K- . . . 24 Medulla and soralia K+ orange-yellow . . . perlata |
| 24 | 23 | Medulla and soralia Pd-, KC+ pink, UV+ ice-blue . . . arnoldii Medulla Pd+ rust red, KC-, UV- . . . robusta |
| 25 | 2 | Isidia and/or soralia present . . . 26 Isidia and/or soralia absent . . . 32 |
| 26 | 25 | Lobes ± isidiate . . . 27 Lobes with granular or farinose soralia . . . 28 |
| 27 | 26 | Isidia cylindrical becoming coralloid, often crowded but sometimes almost absent; medulla Pd+ orange, K+ yellow- orange . . . conspersa Isidia globose or irregular, not branched; medulla Pd+ orange- red, K+ red . . . tinctina |
| 28 | 26 | Soralia laminal; axils not sinuate; rhizines simple or branched, not projecting beyond thallus margin . . . 29 Soralia terminal, at ends of ± ascending, narrow lobes; axils sinuate; rhizines richly branched often projecting beyond thallus margin . . . sinuosa |
| 29 | 28 | Lobes 0. 5-1. 3 cm wide, rounded . . . 30 Lobes <0. 3 cm wide, elongate . . . 31 |
| 30 | 29 | Soredia coarse, granular; medulla Pd+ red, K+ yellow; lobes <1. 3 cm wide . . . caperata Soredia fine, farinose; medulla Pd+ orange, K+ yellow then red; lobes <0. 7 cm wide . . . soredians |
| 31 | 29 | Lobes markedly convex; soralia on the ends of lobes within the thallus, convex; medulla KC+ pink, UV+ ice-blue . . . incurva Lobes ± flat; soralia laminal, flat or excavate; medulla KC+ yellow-orange, UV- . . . mougeotii |
| 32 | 25 | Lower surface jet black; medulla K+ yellow-orange . . . conspersa Lower surface pale brown; medulla K+ dull brown . . . protomatrae |
| 33 | 1 | Without soralia or isidia . . . 34 With soralia and/or isidia . . . 42 |
| 34 | 33 | Upper surface with oval or elongate pseudocyphellae which frequently fuse to form a coarse, ± raised, white network . . . 35 Upper surface devoid of white, ridge-like pseudocyphellae, no white network present . . . 36 |
| 35 | 34 | Medulla Pd+ orange, K+ yellow-orange . . . omphalodes Medulla Pd+ red, K- . . . discordans |
| 36 | 34 | Lobes >2 mm wide, elongate or ± rounded, margins indented or entire; upper surface without pseudocyphellae . . . 37 Lobes <2 mm wide, linear, margin irregularly nodulose; upper surface with minute psudocyphellae . . . stygia |
| 37 | 36 | Upper surface even or wavy, smooth, not transversely ridged; inland . . . 38 Upper surface with transverse ridges and wrinkles; coastal . . . 41 |
| 38 | 37 | Marginal lobes usually present, well developed; folioles absent; apothecia often present . . . 39 Marginal lobes ± absent; thallus of numerous very small, overlapping folioles; apothecia absent . . . laciniatula |
| 39 | 38 | Thallus pale brown, red-brown, olive, or black-brown, ± brown when wet; lobes <1 cm wide, thin, often closely adpressed . . . 40 Thallus grey-brown, dark oily green when wet; lobes <1. 7 cm wide, coriaceous, not closely adpressed . . . acetabulum |
| 40 | 39 | Upper surface with numerous, ± evenly spaced, wart-like, conical papillae; apothecia usually present; thalline exciple swollen, ± papillate . . . exasperata Upper surface smooth, without conical warts; apothecia crowded; thalline exciple very thin, smooth . . . septentrionalis |
| 41 | 37 | Upper surface pale grey-brown to light brown . . . delisei Upper surface brown to black-brown . . . pulla |
| 42 | 33 | Thallus rarely pruinose; upper surface lacking hairs; margins of lobes adpressed . . . 43 Thallus usually pruinose; upper surface with fine white hairs; margins of lobes usually ascending, pubescent . . . subargentifera |
| 43 | 42 | Medulla C+ instantly bright carmine-red . . . 44 Medulla C-, rarely C+ faint pink . . . 46 |
| 44 | 43 | Isidia cylindrical, becoming branched-coralloid, leaving white area when abraded; upper surface shiny . . . 45 Isidia ± globose, derived from soredia, leaving a pale yellow area when abraded; upper surface matt . . . subaurifera |
| 45 | 44 | Upper surface red to olive -brown; mainly on bark or wood . . . glabratula subsp. glabratula Upper surface dark brown to black-brown; mainly on rocks . . . glabratula subsp. fuliginosa |
| 46 | 43 | Thallus lobes >0. 2 cm wide; well defined marginal lobes present . . . 47 Thallus of numerous, thin, flattened, overlapping folioles, <0. 2 cm wide; marginal lobes poorly developed or absent . . . laciniatula |
| 47 | 46 | On rocks . . . 48 On bark or wood . . . 51 |
| 48 | 47 | Isidia not inflated, ± solid, often branched, ± cylindrical . . . 49 Isidia inflated, hollow, clavate or ± spathulate, often decumbent, orientated in all directions . . . exasperatula |
| 49 | 48 | Lobes <0. 6 cm wide; pseudocyphellae absent . . . 50 Lobes <0. 15 cm wide; minute, white pseudocyphellae present . . . disjuncta |
| 50 | 49 | Isidia in ± scattered, coarse clusters, cauliflower-like; thallus yellowish to reddish brown . . . loxodes Isidia diffuse, or ± in contiguous clusters; thallus dark brown . . . verruculifera |
| 51 | 47 | Upper surface with ± crowded, cylindrical isidia or flattened folioles; lower surface pale, apothecia very rare . . . 52 Upper surface with numerous, evenly spaced, conical papillae; lower surface black; apothecia often present . . . exasperata |
| 52 | 51 | Folioles absent; isidia numerous, not resembling small lobes; marginal lobes always well-developed . . . 53 Thallus of numerous, small, thin, overlapping folioles; isidia absent; marginal lobes rarely conspicuous . . . laciniatula |
| 53 | 52 | Isidia clavate or ± spathulate, hollow, simple, often decumbent, orientated in all directions . . . exasperatula Isidia cylindrical, ± erect, solid, often branched-coralloid . . . elegantula |
Current names - Synonyms - Habitat lists (either Current names or Synonyms) - Chemistry lists (either Current names or Synonyms) - Glossary
© British Lichen Society 1997