Checklist of lichens of Wisconsin (USA)
Version 31 December 2018

 

  1. Acarospora americana H. Magn. - Thomson (2003: 26), Thomson (2003: 26 as Acarospora cinereoalba)
  2. Acarospora elevata H. Magn. - Howard (1950: as Acarospora washingtonensis), Douglas (1974: 584 as Acarospora washingtonensis)
  3. Acarospora fuscata (Nyl.) Arnold - Howard (1950: ), Douglas (1974: 584), Thomson (1997: 24), Thomson (2003: 26)
  4. Acarospora moenium (Vain.) Räsänen - Lay (2004: as Aspicilia moenium)
  5. Acarospora schleicheri (Ach.) A. Massal. - Thomson (1997: 33), Bennett (2006: )
  6. Acarospora veronensis A. Massal. - Thomson (1997: 35), Thomson (2003: 26)

  7. Acrocordia cavata (Ach.) R. C. Harris - Thomson (2003: 27)
  8. Acrocordia conoidea (Fr.) Körb. - Thomson (2003: 27)
  9. Acrocordia megalospora (Fink) R. C. Harris - Thomson (2003: 27)

  10. Adelolecia kolaensis (Nyl.) Thomson (1997: 338 as Lecidea conferenda), Hertel & Rambold - Bennett (2006: )

  11. Agonimia opuntiella (Buschardt & Poelt) Vezda - Bennett (2006: )

  12. Ahtiana aurescens (Tuck.) A. Thell & Randlane - Thomson (2003: 28), Bennett & Wetmore (2004: 172 Historical Occurrences)

  13. Alyxoria varia Pers. - Thomson (2003: 156 as Opegrapha varia)

  14. Amandinea dakotensis (H. Magn.) P. May & Sheard - Thomson (2003: 28)
  15. Amandinea milliaria (Tuck.) P. May & Sheard - Thomson (2003: 29)
  16. Amandinea polyspora (Willey in Tuck.) E. Lay & P. May - Thomson (1997: 137 as Buellia polyspora), Thomson (2003: 29), Lay (2004: 17)
  17. Amandinea punctata (Hoffm.) Coppins & Scheid. - Thomson (1997: 138 as Buellia punctata), Thomson (2003: 29), Thomson (2003: 49 as Buellia stigmatea), Lay (2004: 17)

  18. Anaptychia crinalis (Schaer.) Vezda - Thomson (1984: 40 as Anaptychia kaspica), Thomson (2003: 30 erroneously as Anaptychia setifera), Bennett & Wetmore (2004: 172 as Anaptychia setifera Critically Imperiled)
  19. Anaptychia palmulata (Michx.) Vain. - Thomson (2003: 30)

  20. Anisomeridium biforme (Borrer) R. C. Harris - Thomson (2003: 30)
  21. Anisomeridium leucochlorum (Müll. Arg.) R. C. Harris - Thomson (2003: 30)
  22. Anisomeridium polypori (Ellis & Everh.) M. E. Barr - Thomson (2003: 30)

  23. Anzia colpodes (Ach.) Stizenb. - Thomson (2003: 30), Bennett & Wetmore (2004: 172 Historical Occurrences)

  24. Arthonia anglica Coppins - Lendemer et al. (2009: )
  25. Arthonia apatetica (A. Massal.) Th. Fr. - Lay (2004: )
  26. Arthonia atra (Pers.) A. Schneid. - Thomson (2003: 155 as Opegrapha atra)
  27. Arthonia byssacea (Weigel) Almq. - Thomson (2003: 32)
  28. Arthonia caudata Willey - Lay (2004: ) Fungus
  29. Arthonia didyma Körb. - Thomson (2003: 33)
  30. Arthonia diffusa Nyl. - Thomson (2003: 35 as Arthonia willeyi) fide Lendemer 2004
  31. Arthonia diffusella Fink ex J. Hedrick - Bennett (2006)
  32. Arthonia dispersa (Schrad.) Dufour - Brodo (1967: 211), Thomson (2003: 33)
  33. Arthonia fuliginosa (Schaer.) Flotow - Thomson (2003: 33)
  34. Arthonia glebosa Tuck. - Bennett (2006: )
  35. Arthonia granosa de Lesd. - Brodo (1967: 211), Thomson (2003: 33)
  36. Arthonia helvola (Nyl.) Nyl. - Lay (2004: )
  37. Arthonia patellulata Nyl. - Brodo (1967: 211), Thomson (1997: 47), Thomson (2003: 34), Lay (2004: 17)
  38. Arthonia polymorpha Ach. - Thomson (2003: 34)
  39. Arthonia punctiformis Ach. - Brodo (1967: 211), Thomson (2003: 34)
  40. Arthonia radiata (Pers.) Ach. - Brodo (1967: 211), Thomson (2003: 34)
  41. Arthonia rubella (Fée) Nyl. - Bennett (2006: )
  42. Arthonia rupicola Fink - Thomson (2003: 34)
  43. Arthonia spadicea Leight. - Thomson (2003: 35)

  44. Arthothelium hallii (Tuck.) Zahlbr. - Thomson (2003: 35)
  45. Arthothelium spectabile A. Massal. - Thomson (2003: 35)

  46. Arthrosporum populorum A. Massal. - Thomson (2003: 41 as Bacidia populorum), Lay (2004: 17)

  47. Aspicilia cinerea (L.) Körb. - Thomson (1997: 68), Thomson (2003: 36)
  48. Aspicilia laevata (Ach.) Arnold - Thomson (2003: 37)
  49. Aspicilia limitata (H. Magn.) J. W. Thomson - Thomson (2003: 37)
  50. Aspicilia verrucigera Hue - Lay (2004: )

  51. Athallia holocarpa (Hoffm.) Arup, Frödén & Søchting - Thomson (1997: 164 as Caloplaca holocarpa), Thomson (2003: 56 as Caloplaca holocarpa), Lay (2004: 18 as Caloplaca holocarpa)
  52. Athallia vitellinula (Nyl.) Arup, Frödén & Søchting - Thomson (2003: 58 as Caloplaca vitellinula)

  53. Bacidia bagliettoana (A. Massal. & De Not.) Jatta - Brodo (1967: 212 as Bacidia muscorum), Thomson (1997: 99), Thomson (2003: 39)
  54. Bacidia circumspecta (Norrl. & Nyl.) Malme - Thomson (1997: 110 as Bacidia sphaeroides), Lay (2004: 18)
  55. Bacidia coprodes (Körb.) Lettau - Brodo (1967: 212 as Bacidia pammellii), Brodo (1967: 212 erroneously as Bacidia trachona), Thomson (1997: 112 as Bacidia trachona), Thomson (2003: 40 as Bacidia granosa)
  56. Bacidia diffracta S. Ekman - Thomson (2003: 40)
  57. Bacidia laurocerasi (Delise ex Duby) Zahlbr. subsp. laurocerasi - Thomson (2003: 40)
  58. Bacidia polychroa (Th. Fr.) Körb. - Thomson (2003: 41)
  59. Bacidia rubella (Hoffm.) A. Massal. - Thomson (1997: 107), Thomson (2003: 41)
  60. Bacidia schweinitzii (Fr. ex Tuck.) A. Schneid. - Thomson (2003: 41)
  61. Bacidia subincompta (Nyl.) Arnold - Thomson (2003: 42)
  62. Bacidia suffusa (Fr.) A. Schneid. - Thomson (2003: 42)

  63. Bacidina egenuloidea (Fink) S. Ekman - Thomson (2003: 43)
  64. Bacidina inundata (Fr.) Vezda - Brodo (1967: 212), Thomson (2003: 43)

  65. Baeomyces rufus (Hudson) Rebent. - Thomson (2003: 43)

  66. Bagliettoa calciseda DC. - Thomson (2003: 242 as Verrucaria calciseda)

  67. Biatora helvola Körb. ex Hellbom - Thomson (1997:349 as Lecidea helvola), Thomson (2003: 45)
  68. Biatora longispora (Degel.) Lendemer & Printzen - Lay (2004: )
  69. Biatora toensbergii Holien & Printzen - Lay (2004: )
  70. Biatora vernalis (L.) Fr. - Thomson (2003: 45)

  71. Bilimbia microcarpa (Th. Fr.) Th. Fr. - Thomson (1997: 105 as Bacidia microcarpa), Thomson (2003: 149 as Mycobilimbia microcarpa)
  72. Bilimbia sabuletorum (Schreb.) Arnold - Brodo (1967: 212 as Bacidia sabuletorum), Thomson (1997: 422 as Mycobilimbia sabuletorum), Thomson (2003: 149 as Mycobilimbia sabuletorum)

  73. Blastenia ferruginea (Hudson) Th. Fr. - Thomson (2003: 55 as Caloplaca ferruginea)

  74. Bryobilimbia ahlesii (Körber) Fryday, Printzen & S. Ekman - Bennett (2006: as Lecidea delincta)
  75. Bryobilimbia hypnorum Lib. - Thomson (1997: 351 as Lecidea hypnorum), Thomson (2003: 149 as Mycobilimbia hypnorum)

  76. Bryoria capillaris (Ach.) Brodo & D. Hawksw. - Thomson (2003: 46), Bennett & Wetmore (2004: 172 Critically Imperiled)
  77. Bryoria fremontii (Tuck.) Brodo & D. Hawksw. - Howard (1950: as Alectoria fremontii), Douglas (1974: 584 as Alectoria fremontii)
  78. Bryoria furcellata (Fr.) Brodo & D. Hawksw. - Thomson (2003: 46)
  79. Bryoria fuscescens (Gyeln.) Brodo & D. Hawksw. - Bennett (2006: )
  80. Bryoria nadvornikiana (Gyeln.) Brodo & D. Hawksw. - Thomson (2003: 46), Bennett & Wetmore (2004: 172 Critically Imperiled)
  81. Bryoria trichodes (Michx.) Brodo & D. Hawksw. subsp. trichodes - Thomson (1984: 68), Thomson (2003: 46)

  82. Buellia arnoldii Servít & Nádv. - Thomson (2003: 48)
  83. Buellia badia (Fr.) A. Massal. - Thomson (2003: ), Thomson (2003: 50 as Buellia turgescens)
  84. Buellia disciformis (Fr.) Mudd - Thomson (1997: 129), Thomson (2003: 48)
  85. Buellia erubescens Arnold - Thomson (1997: 131), Thomson (2003: 48), Thomson (2003: 50 as Buellia stillingiana)
  86. Buellia maculata Bungartz - Thomson (2003: )
  87. Buellia mamillana (Tuck.) W. A. Weber - Thomson (2003: 49)
  88. Buellia nigra (Fink) Sheard - Bennett (2006: )
  89. Buellia schaereri De Not. - Thomson (2003: 48), Lay (2004: 18)
  90. Buellia spuria (Schaer.) Anzi - Thomson (1997: 139), Bennett (2006: )
  91. Buellia vilis Th. Fr. - Thomson (1997: 141), Thomson (2003: 50)

  92. Caeruleum immersum (Fink) K. Knudsen & B. Abbott - Thomson (2003: 26 as Acarospora immersa), Thomson (2003: as Myriospora immersa)

  93. Calicium abietinum Pers. - Thomson (1997: 143), Thomson (2003: 50)
  94. Calicium glaucellum Ach. - Thomson (2003: 51)
  95. Calicium parvum Tibell - Thomson (2003: 52)
  96. Calicium salicinum Pers. - Thomson (2003: 52)
  97. Calicium trabinellum - Thomson (1997: 145), Thomson (2003: 52)

  98. Caloplaca ahtii Søchting - Bennett (2006: )
  99. Caloplaca atroalba (Tuck.) Zahlbr. - Thomson (2003: 54)
  100. Caloplaca brunneola Wetmore - Thomson (2003: 54)
  101. Caloplaca cerina (Ehrh. ex Hedw.) Th. Fr. - Thomson (1997: 154), Thomson (2003: 54), Lay (2004: 18)
  102. Caloplaca fraudans (Th. Fr.) Oliv. - Thomson (1997: 162)
  103. Caloplaca microphyllina (Tuck.) Hasse - Thomson (2003: 57)
  104. Caloplaca parvula Wetmore - Bennett (2006: )
  105. Caloplaca pollinii (A. Massal.) Jatta - Thomson (2003: 57)
  106. Caloplaca saxicola (Hoffm.) Nordin - Thomson (1997: 169), Thomson (2003: 57)
  107. Caloplaca sideritis (Tuck.) Zahlbr. - Thomson (2003: 58)
  108. Caloplaca ulmorum (Fink) Fink - Thomson (2003: 58)

  109. Candelaria concolor (Dickson) Stein - Thomson (2003: 59), Lay (2004: 18)
  110. Candelaria fibrosa (Fr.) Müll. Arg. - Thomson (2003: 59)

  111. Candelariella aurella (Hoffm.) Zahlbr. - Thomson (1997: 182), Thomson (2003: 60)
  112. Candelariella coralliza (Nyl.) H. Magn. - Thomson (1997: 183), Thomson (2003: 60)
  113. Candelariella efflorescens R. C. Harris & W. R. Buck - Thomson (1997: 185), Thomson (2003: 60)
  114. Candelariella reflexa (Nyl.) Lettau - Lay (2004: )
  115. Candelariella vitellina (Hoffm.) Müll. Arg. - Thomson (1997: 189), Thomson (2003: 61), Lay (2004: 18)
  116. Candelariella xanthostigma (Ach.) Lettau - Thomson (1997: 190), Thomson (2003: 61)

  117. Canoparmelia texana (Tuck.) Elix & Hale - Thomson (2003: 62)

  118. Carbonicola anthracophila (Nyl.) P. James & Gotth. Schneider - Thomson (2003: 109 as Hypocenomyce anthracophila)

  119. Catapyrenium cinereum (Pers.) Körb. - Thomson (1984: 210 as Dermatocarpon cinereum)

  120. Catillaria chalybeia (Borrer) A. Massal. - Thomson (1997: 196), Thomson (2003: 64)
  121. Catillaria lenticularis (Ach.) Th. Fr. - Bennett (2006: )
  122. Catillaria nigroclavata (Nyl.) Schuler - Lay (2004: )

  123. Catinaria atropurpurea (Schaer.) Vezda & Poelt - Thomson (2003: 64 as Catillaria atropurpurea)

  124. Cetraria arenaria Kärnefelt - Thomson (2003: 65), Bennett & Wetmore (2004: 172 Historical Occurrences)
  125. Cetraria ericetorum Opiz subsp. ericetorum - Thomson (1984: 79), Bennett (2006: )

  126. Cetrelia cetrarioides (Del.) W. L. Culb. & C. F. Culb. - Thomson (2003: 66)
  127. Cetrelia chicitae (W. L. Culb.) W. L. Culb. & C. F. Culb. - Thomson (2003: 66)
  128. Cetrelia olivetorum (Nyl.) W. L. Culb. & C. F. Culb. - Thomson (2003: 66)

  129. Chaenotheca brunneola (Ach.) Müll. Arg. - Thomson (2003: 67)
  130. Chaenotheca chrysocephala (Turner ex Ach.) Th. Fr. - Thomson (1997: 205), Thomson (2003: 67)
  131. Chaenotheca ferruginea (Turner ex Sm.) Mig. - Thomson (2003: 68)
  132. Chaenotheca furfuracea (L.) Tibell - Thomson (1997: 210 as Coniocybe furfuracea), Thomson (2003: 68)
  133. Chaenotheca gracillima (Vain.) Tibell - Lay (2004: )
  134. Chaenotheca laevigata Nádv. - Thomson (2003: 68)
  135. Chaenotheca phaeocephala (Turner) Th. Fr. - Thomson (1997: 206), Thomson (2003: 68), Bennett (2006: )
  136. Chaenotheca stemonea (Ach.) Müll. Arg. - Thomson (2003: 68)
  137. Chaenotheca trichialis (Ach.) Th. Fr. - Thomson (2003: 69)
  138. Chaenotheca xyloxena Nádv. - Thomson (2003: 69)

  139. Chrismofulvea dialyta (Nyl.) Marbach - Thomson (2003: 48 as Buellia dialyta)

  140. Chrysothrix caesia (Flot.) Ertz & Tehler - Brodo (1967: 211 as Arthonia caesia), Thomson (2003: 30 as Arthonia caesia), Thomson (2003: 33 as Arthonia lecideella), Lay (2004: 17 as Arthonia caesia)
  141. Chrysothrix candelaris (L.) J. R. Laundon - Lay (2004: )

  142. Circinaria caesiocinerea (Nyl. ex Malbr.) A. Nordin, S. Savić & Tibell - Thomson (1997: 65 as Aspicilia caesiocinerea), Thomson (2003: 36 as Aspicilia caesiocinerea)
  143. Circinaria contorta (Hoffm.) A. Nordin, S. Savić & Tibell - Thomson (2003: 37 as Aspicilia contorta)

  144. Cladonia acuminata (Ach.) Norrlin - Thomson (1984: 152 as Cladonia norrlinii), Thomson (2003: 76), Bennett & Wetmore (2004: 173 Extinct)
  145. Cladonia amaurocraea (Flörke) Schaer. - Thomson (1984: 107), Thomson (2003: 76)
  146. Cladonia apodocarpa Robbins - Thomson (2003: 76)
  147. Cladonia arbuscula (Wallr.) Flot. - Thomson (2003: 71 as Cladina arbuscula), Bennett & Wetmore (2004: 172 Historical Occurrences)
  148. Cladonia borealis S. Stenroos - Bennett (2006: )
  149. Cladonia botrytes (Hag.) Willd. - Thomson (1984: 114), Thomson (2003: 77)
  150. Cladonia caespiticia (Pers.) Flörke - Thomson (2003: 77), Thomson (2003: 77)
  151. Cladonia cariosa (Ach.) Spreng. - Brodo (1967: 212), Thomson (1984: 116), Thomson (2003: 77)
  152. Cladonia carneola (Fr.) Fr. - Lay (2004: )
  153. Cladonia cenotea (Ach.) Schaer. - Thomson (1984: 118), Thomson (2003: 78)
  154. Cladonia cervicornis (Hoffm.) Ahti - Thomson (2003: as )
  155. Cladonia chlorophaea ( Flörke ex. Sommerf.) Spreng. - Brodo (1967: 212), Thomson (1984: 119), Thomson (2003: 78)
  156. Cladonia coccifera (L.) Willd. - Thomson (1984: 121)
  157. Cladonia coniocraea (Flörke) Spreng. - Brodo (1967: 212), Thomson (1984: 122), Thomson (2003: 78)
  158. Cladonia crispata (Ach.) Flot. var. crispata - Thomson (1984: 125), Thomson (2003: 79)
  159. Cladonia cristatella Tuck. - Brodo (1967: 212), Thomson (2003: 80)
  160. Cladonia cryptochlorophaea Asah. - Thomson (1984: 126), Thomson (2003: 80)
  161. Cladonia cylindrica (A. Evans) A. Evans - Thomson (2003: 80)
  162. Cladonia decorticata (Flörke) Speng. - Brodo (1967: 212), Thomson (1984: 128), Thomson (2003: 80), Bennett & Wetmore (2004: 172 Critically Imperiled)
  163. Cladonia deformis (L.) Hoffm. - Thomson (1984: 129), Thomson (2003: 81)
  164. Cladonia didyma (Fée) Vain. - Thomson (2003: 81)
  165. Cladonia digitata (L.) Hoffm. - Thomson (1984: 131), Thomson (2003: 81)
  166. Cladonia dimorphoclada Robbins - Thomson (2003: 81)
  167. Cladonia farinacea (Vain.) A. Evans - Thomson (2003: 82)
  168. Cladonia fimbriata (L.) Fr. - Thomson (1984: 133), Thomson (1984: 144 as Cladonia major), Thomson (2003: 82)
  169. Cladonia floerkeana (Fr.) Flörke - Thomson (1984: 134), Thomson (2003: 82)
  170. Cladonia furcata (Hudson) Schrad. - Brodo (1967: 212), Thomson (2003: 83)
  171. Cladonia gracilis (L.) Willd. subsp. turbinata (Ach.) Ahti - Thomson (1984: 136), Thomson (2003: 83)
  172. Cladonia gracilis (L.) Willd. subsp. gracilis - Thomson (1984: 137)
  173. Cladonia grayi Merrl. - Thomson (1984: 139), Thomson (2003: 83)
  174. Cladonia humilis (With.) J. R. Laundon - Thomson (2003: )
  175. Cladonia incrassata Flörke - Thomson (2003: 84), Bennett & Wetmore (2004: 172 Critically Imperiled)
  176. Cladonia macilenta var. bacillaris (Genth) Schaerer - Thomson (1984: 111 as Cladonia bacillaris), Thomson (2003: 77 as Cladonia bacillaris), Lay (2004: 18) The name Cladonia bacillaris is available
  177. Cladonia macilenta Hoffm. var. macilenta - Thomson (2003: 84)
  178. Cladonia merochlorophaea Asah. - Thomson (1984: 143), Thomson (2003: 84)
  179. Cladonia mitis Sandst. - Thomson (1984: 148), Thomson (2003: 71 as Cladina mitis)
  180. Cladonia multiformis Merr. - Thomson (1984: 149), Thomson (2003: 84)
  181. Cladonia parasitica (Hoffm.) Hoffm. - Thomson (2003: 85), Lay (2004: 18)
  182. Cladonia petrophila R. C. Harris - Harris (1992: 329 First record), Thomson (2003: 85)
  183. Cladonia peziziformis (With.) J. R. Laundon - Brodo (1967: 212 as Cladonia capitata), Thomson (2003: 85)
  184. Cladonia phyllophora Hoffm. - Thomson (2003: 86)
  185. Cladonia pleurota (Flörke) Schaer. - Thomson (1984: 154), Thomson (2003: 86)
  186. Cladonia pocillum (Ach.) O. Rich. - Thomson (1984: 156), Thomson (2003: 86)
  187. Cladonia pyxidata (L.) Hoffm. - Brodo (1967: 212), Thomson (1984: 158), Thomson (2003: 87)
  188. Cladonia ramulosa (With.) J. R. Laundon - Thomson (1984: 109 as Cladonia anomaea), Thomson (2003: 87)
  189. Cladonia rangiferina (L.) F. H. Wigg. - Thomson (1984: 159), Thomson (2003: 72 as Cladina rangiferina)
  190. Cladonia rei Schaerer - Brodo (1967: 212 as Cladonia nemoxyna), Thomson (2003: 87)
  191. Cladonia robbinsii A. Evans - Thomson (2003: 88)
  192. Cladonia scabriuscula (Del. in Duby) Nyl. - Thomson (1984: 160), Thomson (2003: 88)
  193. Cladonia squamosa (Scop.) Hoffm. - Thomson (1984: 161), Thomson (2003: 88)
  194. Cladonia stellaris (Opiz) Pouzar & Vezda - Thomson (1984: 163), Thomson (2003: 72 as Cladina stellaris)
  195. Cladonia strepsilis (Ach.) Grognot - Thomson (2003: 89)
  196. Cladonia stygia (Fr.) Ahti - Thomson (2003: 72 as Cladina stygia), Bennett & Wetmore (2004: 172 Critically Imperiled)
  197. Cladonia subcariosa Nyl. - Thomson (2003: ), Thomson (2003: 86 as Cladonia polycarpoides), Thomson (2003: 88 as Cladonia sobolescens)
  198. Cladonia subtenuis (Abb.) Hale & Culb. - Thomson (2003: 72 as Cladina subtenuis)
  199. Cladonia subulata (L.) F. H. Wigg. - Thomson (2003: 89)
  200. Cladonia sulphurina (Michx.) Fr. - Thomson (2003: 89), Bennett & Wetmore (2004: 172 Critically Imperiled)
  201. Cladonia symphycarpia (Ach.) Fr. - Thomson (1984: 170), Bennett (2006: )
  202. Cladonia turgida Ehrh. ex Hoffm. - Thomson (1984: 172), Thomson (2003: 90)
  203. Cladonia uncialis (L.) Weber ex F. H. Wigg. - Thomson (1984: 173), Thomson (2003: 90)
  204. Cladonia verticillata (Hoffm.) Schaer. - Thomson (1984: 174), Thomson (2003: 90)

  205. Clavascidium lacinulatum (Ach.) M. Prieto var. lacinulatum - Thomson (2003: 63 as Catapyrenium lacinulatum)
  206. Clavascidium umbrinum (Breuss) Breuss - Thomson (2003: 64 as Catapyrenium umbrinum)

  207. Coenogonium luteum (Dicks.) Kalb & Lücking - Thomson (2003: 98 as Dimerella lutea)
  208. Coenogonium pineti (Schrad. ex Ach.) Lücking & Lumbsch - Thomson (2003: 98 as Dimerella pineti)

  209. Collema flaccidum (Ach.) Ach. - Thomson (2003: 92)
  210. Collema furfuraceum (Schaer.) Du Rietz - Thomson (1984: 187), Thomson (2003: 92)
  211. Collema nigrescens (Huds.) DC. - Thomson (2003: 93)
  212. Collema pustulatum Ach. - Thomson (2003: 93)
  213. Collema subflaccidum Degel. - Thomson (2003: 94)

  214. Cresponea chloroconia (Tuck.) Egea & Torrente - Thomson (2003: 95)

  215. Cyphelium lucidum (Th. Fr.) Th. Fr. - Thomson (2003: 96)
  216. Cyphelium tigillare (Ach.) Ach. - Thomson (1997: 214), Thomson (2003: 96)

  217. Cystocoleus ebeneus (Dillwyn) Thwaites - Thomson (2003: 96)

  218. Dermatocarpon americanum Vain. - Heidmarsson (2003: 466)
  219. Dermatocarpon luridum (With.) J. R. Laundon - Thomson (1984: 213 as Dermatocarpon fluviatile), Thomson (2003: 97)
  220. Dermatocarpon miniatum (L.) Mann. - Brodo (1967: 211), Thomson (1984: 219), Thomson (2003: 97)

  221. Dimelaena oreina (Ach.) Norman - Thomson (1997: 216), Thomson (2003: 98)

  222. Diploschistes muscorum (Scop.) R. Sant. - Thomson (1997: 218), Thomson (2003: 99)
  223. Diploschistes scruposus (Schreb.) Norman - Thomson (1997: 218), Thomson (2003: 99)

  224. Diplotomma alboatrum (Hoffm.) Flot. - Thomson (1997: 127 as Buellia alboatra), Thomson (2003: 100)

  225. Dirinaria frostii (Tuck.) Hale & W. L. Culb. - Thomson (2003: 100), Bennett & Wetmore (2004: 172 Historical Occurrences)

  226. Distopyrenis americana Aptroot - Lay (2004: )

  227. Enchylium bachmanianum (Fink) Otálora, P. M. Jørg. & Wedin - Thomson (2003: 92 as Collema bachmanianum)
  228. Enchylium conglomeratum (Hoffm.) Otálora, P. M. Jørg. & Wedin - Thomson (2003: 92 as Collema conglomeratum)
  229. Enchylium polycarpon (Hoffm.) Otálora, P. M. Jørg. & Wedin - Thomson (1984: Collema polycarpon), Thomson (1997: 190 as Collema polycarpon), Thomson (2003: 93 as Collema polycarpon), Bennett & Wetmore (2004: 172 as Collema polycarpon Historical Occurrences)
  230. Enchylium tenax (Sw.) Gray - Thomson (1984: as Collema tenax), Thomson (1997: 192 as Collema tenax), Thomson (2003: 94 as Collema tenax)

  231. Endocarpon diffractellum (Nyl.) Gueidan & Cl. Roux - Thomson (2003: 220 as Staurothele diffractella)
  232. Endocarpon pusillum Hedwig - Brodo (1967: 211), Thomson (2003: 101)

  233. Eopyrenula intermedia Coppins ex Aptroot - Thomson (2003: 101)

  234. Ephebe lanata (L.) Vain. - Thomson (1984: 225), Thomson (2003: 102), Bennett & Wetmore (2004: 173 Extinct)

  235. Epigloea soleiformis Döbbeler - Lay (2004: )

  236. Evernia mesomorpha Nyl. - Thomson (1984: 229), Thomson (2003: 102), Lay (2004: 18)
  237. Evernia prunastri (L.) Ach. - Thomson (2003: 103), Bennett & Wetmore (2004: 172 Historical Occurrences)

  238. Flavoparmelia baltimorensis (Gyelnik & Fóriss) Hale - Thomson (2003: 103)
  239. Flavoparmelia caperata (L.) Hale - Thomson (2003: 103)

  240. Flavoplaca citrina (Hoffm.) Arup, Frödén & Søchting - Thomson (1997: 155 as Caloplaca citrina), Thomson (2003: 55 as Caloplaca citrina)

  241. Flavopunctelia flaventior (Stirt.) Hale - Thomson (2003: 104)
  242. Flavopunctelia soredica (Nyl.) Hale - Thomson (2003: 104)

  243. Fuscidea pusilla Tønsberg - Lay (2004: )

  244. Fuscopannaria ahlneri (P. M. Jørg) P. M. Jørg. - Thomson (2003: )
  245. Fuscopannaria leucosticta (Tuck.) P. M. Jørg. - Bennett & Wetmore (2004: ), Bennett & Wetmore (2004: 172 Critically Imperiled)
  246. Fuscopannaria praetermissa (Nyl.) P. M. Jørg. - Bennett (2006: )

  247. Gassicurtia vernicoma (Tuck.) Marbach - Thomson (2003: 50 as Buellia vernicoma)

  248. Graphis intricata Fée - Thomson (2003: 105)
  249. Graphis scripta (L.) Ach. - Thomson (2003: 105)

  250. Gyalecta fagicola (Hepp ex Arnold) Zwackh - Thomson (2003: 156 as Pachyphiale fagicola)
  251. Gyalecta truncigena (Ach.) Hepp - Thomson (2003: 106)

  252. Gyalolechia flavorubescens (Hudson) Søchting, Frödén & Arup - Thomson (2003: 56 as Caloplaca flavorubescens)
  253. Gyalolechia flavovirescens (Wulf.) Søchting, Frödén & Arup - Thomson (1997: 161 as Caloplaca flavovirescens), Thomson (2003: 56 as Caloplaca flavovirescens)
  254. Gyalolechia xanthostigmoidea (Räsänen) Søchting, Frödén & Arup - Thomson (1997: 158 as Caloplaca discolor), Thomson (2003: 55 as Caloplaca discolor)

  255. Heppia lutosa (Ach.) Nyl. - Thomson (1997: 244), Thomson (2003: 106), Bennett & Wetmore (2004: 172 Imperiled)

  256. Heterodermia galactophylla (Tuck.) W. L. Culb. - Thomson (2003: 107)
  257. Heterodermia hypoleuca (Muhl.) Trevisan - Thomson (2003: 107)
  258. Heterodermia pseudospeciosa (Kurok.) W. L. Culb. - Thomson (2003: 107)
  259. Heterodermia speciosa (Wulfen) Trevisan - Thomson (2003: 108)

  260. Hyperphyscia adglutinata (Flörke) H. Mayrh. & Poelt - Thomson (2003: 108)
  261. Hyperphyscia syncolla (Tuck. ex Nyl.) Kalb - Thomson (2003: 108)

  262. Hypocenomyce scalaris (Ach. ex Lilj.) M. Choisy - Thomson (1997: 248), Thomson (2003: 110)

  263. Hypogymnia physodes (L.) Nyl. - Thomson (1984: 241), Thomson (2003: 110)
  264. Hypogymnia tubulosa (Schaer.) Hav. - Thomson (2003: 111), Bennett & Wetmore (2004: 172 Critically Imperiled)

  265. Hypotrachyna revoluta (Flörke) Hale - Lay (2004: )

  266. Icmadophila ericetorum (L.) Zahlbr. - Thomson (1997: 249), Thomson (2003: 111)

  267. Imshaugia aleurites (Ach.) S. F. Meyer - Thomson (1984: 321 as Parmeliopsis aleurites), Thomson (2003: 112)
  268. Imshaugia placorodia (Ach.) S. F. Meyer - Thomson (2003: 112)

  269. Ionaspis lacustris (With.) Lutzoni - Bennett (2006: )

  270. Lasallia papulosa (Ach.) Llano - Thomson (1984: 245), Thomson (2003: 113)

  271. Lathagrium fuscovirens (With.) Otálora, P.M. Jørg. & Wedin - Thomson (1984: 192 as Collema tuniforme), Thomson (2003: 93 as Collema fuscovirens)
  272. Lathagrium undulatum (Laurer ex Flot.) Otálora, P. M. Jørg. & Wedin - Thomson (2003: 94 as Collema undulatum)

  273. Lecania cyrtella (Ach.) Th. Fr. - Lay (2004: )
  274. Lecania dubitans (Nyl.) A. L. Sm. - Thomson (2003: 114)
  275. Lecania erysibe (Ach.) Mudd - Thomson (1997: 258), Thomson (2003: 114)
  276. Lecania fuscella (Schaer.) A. Massal. - Thomson (2003: 114)
  277. Lecania naegelii (Hepp) Diederich & van den Boom - Thomson (2003: 40 as Bacidia naegelii), Thomson (2003: )
  278. Lecania nylanderiana A. Massal. - Thomson (2003: 114)

  279. Lecanora albella (Pers.) Ach. var. albella - Thomson (2003: 117)
  280. Lecanora albellula (Nyl.) Th. Fr. - Thomson (1997: 299 as Lecanora piniperda), Thomson (2003: 118)
  281. Lecanora allophana (Ach.) Nyl. - Thomson (1997: 266), Thomson (2003: 118)
  282. Lecanora argentata (Ach.) Malme - Thomson (2003: 118)
  283. Lecanora argentea Oxner & Volkova - Thomson (1997: 281 as Lecanora fuliginosa), Bennett (2006: )
  284. Lecanora cadubriae (A. Massal.) Hedl. - Thomson (1997: 271)
  285. Lecanora caesiorubella Ach. subsp. caesiorubella - Thomson (2003: 119)
  286. Lecanora carpinea (L.) Vain. - Thomson (2003: 119)
  287. Lecanora cateilea (Ach.) A. Massal. - Bennett (2006: )
  288. Lecanora cenisia Ach. - Thomson (1997: 272), Thomson (2003: 119)
  289. Lecanora chlarotera Nyl. - Thomson (1997: 273), Thomson (1997: 301 as Lecanora rugosella), Thomson (2003: 119), Thomson (2003: 122 as Lecanora rugosella)
  290. Lecanora circumborealis Brodo & Vitik. - Thomson (1997: 274), Thomson (2003: 120)
  291. Lecanora crenulata Hook. - Thomson (1997: 277), Thomson (2003: 120)
  292. Lecanora dispersa (Pers.) Sommerf. - Thomson (1997: 278), Thomson (2003: 120)
  293. Lecanora expallens Ach. - Thomson (1997: 280), Bennett (2006: )
  294. Lecanora fuscescens (Sommerf.) Nyl. - Thomson (2003: )
  295. Lecanora glabrata (Ach.) Malme - Thomson (2003: 120)
  296. Lecanora hagenii (Ach.) Ach. - Thomson (1997:286), Thomson (2003: 120)
  297. Lecanora hybocarpa (Tuck.) Brodo - Thomson (2003: 121)
  298. Lecanora hypoptoides (Nyl.) Nyl. - Thomson (2003: 121)
  299. Lecanora intricata (Ach.) Ach.- Thomson (1997: 288), Thomson (2003: 122)
  300. Lecanora invadens H. Magn. - Bennett (2006: )
  301. Lecanora iowensis Fink - Thomson (2003: 122)
  302. Lecanora meridionalis H. Magn. - Lay (2004: )
  303. Lecanora muralis (Schreber) Rabenh. - Thomson (1997: 295), Thomson (2003: 122)
  304. Lecanora opiniconensis Brodo - Thomson (2003: 122)
  305. Lecanora perplexa Brodo - Thomson (1997: 298), Thomson (2003: 123)
  306. Lecanora polytropa (Ehrh. in Hoffm.) Rabenh. - Thomson (1997: 299), Thomson (2003: 123)
  307. Lecanora pulicaris (Pers.) Ach. - Thomson (1997: 301), Thomson (2003: 123)
  308. Lecanora saligna (Schrader) Zahlbr. - Thomson (2003: 124)
  309. Lecanora sambuci (Pers.) Nyl. - Lay (2004: )
  310. Lecanora strobilina (Sprengel) Kieffer - Thomson (2003: 124)
  311. Lecanora subimmergens Vain. - Thomson (2003: 124)
  312. Lecanora subintricata (Nyl.) Th. Fr. - Thomson (1997: 307), Thomson (2003: 125)
  313. Lecanora subrugosa Nyl. - Thomson (1997: 308), Thomson (2003: 125)
  314. Lecanora symmicta (Ach.) Ach. - Thomson (1997: 309), Thomson (2003: 125)
  315. Lecanora thysanophora R. C. Harris - Thomson (2003: 125)
  316. Lecanora valesiaca (Müll. Arg.) Stizenb. - Thomson (2003: 126)
  317. Lecanora varia (Hoffm.) Ach. - Thomson (1997: 311), Thomson (2003: 126)
  318. Lecanora wisconsinensis H. Magn. - Thomson (2003: 126)

  319. Lecidea albohyalina (Nyl.) Th. Fr. - Thomson (2003: 44 as Biatora albohyalina)
  320. Lecidea carnulenta (Tuck.) Fink - Thomson (2003: 127)
  321. Lecidea cyrtidia Tuck. - Thomson (2003: 127)
  322. Lecidea lapicida (Ach.) Ach. - Thomson (2003: 127)
  323. Lecidea nylanderi (Anzi) Th. Fr. - Thomson (1997: 365), Thomson (2003: 128)
  324. Lecidea plana (J. Lahm) Nyl. - Lay (2004: )
  325. Lecidea plebeja Nyl. - Thomson (1997: 374), Thomson (2003: 128)
  326. Lecidea virginiensis Calk. & Nyl. - Thomson (2003: 128)

  327. Lecidella asema (Nyl.) Knoph & Hertel - Bennett (2006: )
  328. Lecidella carpathica Körb. - Thomson (1997: 395), Thomson (2003: 129)
  329. Lecidella elaeochroma (Ach.) Hazwl. - Thomson (2003: 129)
  330. Lecidella euphorea (Flörke) Hertel - Thomson (1997: 398), Thomson (2003: 130)
  331. Lecidella patavina (A. Massal.) Knoph & Leuckert - Thomson (1997: 399 as Lecidella inamoena), Thomson (2003: 130)
  332. Lecidella stigmatea (Ach.) Hertel & Leuck. - Brodo (1967: 212 as Lecidea stigmatea), Thomson (1997: 402), Thomson (2003: 130)

  333. Leimonis erratica (Körb.) R. C. Harris & Lendemer - Thomson (2003: 147 as Micarea erratica)

  334. Lempholemma polyanthes (Bernh.) Malme - Bennett (2006: )

  335. Lepra amara (Ach.) Hafellner - Thomson (2003: 171 as Pertusaria amara)
  336. Lepra multipunctoides (Dibben) Lendemer & R. C. Harris - Thomson (2003: 172 as Pertusaria multipunctoides)

  337. Lepraria finkii Nyl. - Thomson (2003: 131 as Lepraria lobificans)
  338. Lepraria incana (L.) Ach. - Thomson (2003: 131)
  339. Lepraria membranacea (Dickson) Vain. - Thomson (2003: 132 as Leproloma membranaceum)
  340. Lepraria neglecta (Nyl.) Erichsen - Thomson (2003: 132), Thomson (2003: 131 erroneously as Lepraria caesioalba), Bennett (2006: erroneously as Lepraria cacuminum)
  341. Lepraria rigidula (B. de Lesd.) Tønsberg - Lay (2004: )
  342. Lepraria vouauxii (Hue) R. C. Harris - Thomson (2003: 132 as Leproloma vouauxii)

  343. Leptogium arsenei Sierk - Thomson (2003: 133), Bennett & Wetmore (2004: 172 Critically Imperiled)
  344. Leptogium burnetiae C. W. Dodge - Bennett (2006: )
  345. Leptogium byssinum (Hoffm.) Zwackh - Bennett & Bartkowiak (2013: 72)
  346. Leptogium corticola (Taylor) Tuck. - Thomson (2003: 133)
  347. Leptogium cyanescens (Rabenh.) Körb. - Thomson (2003: 134)
  348. Leptogium hirsutum Sierk - Thomson (2003: 134)
  349. Leptogium milligranum Sierk - Thomson (2003: 135)
  350. Leptogium rivulare (Ach.) Mont. - Bennett & Bartkowiak (2013: 73)
  351. Leptogium saturninum (Dicks.) Nyl. - Thomson (1984: 262), Thomson (2003: 135)

  352. Lichinella cribellifera (Nyl.) P. P. Moreno & Egea - Bennett (2006: )
  353. Lichinella nigritella (Lettau) P. P. Moreno & Egea - Thomson (2003: 136)

  354. Lithothelium hyalosporum (Nyl.) Aptroot - Thomson (2003: 136)
  355. Lithothelium phaeosporum (R. C. Harris) Aptroot - Thomson (2003: 136)
  356. Lithothelium septemseptatum (R. C. Harris) Aptroot - Lay (2004: )

  357. Lobaria pulmonaria (L.) Hoffm. - Thomson (2003: 137)
  358. Lobaria quercizans Michx. - Thomson (2003: 137)

  359. Lopadium disciforme (Flot.) Kullhem - Thomson (2003: )
  360. Lopadium pezizoideum (Ach.) Körb. - Thomson (2003: 138)

  361. Loxospora cismonica (Beltr.) Hafellner - Thomson (2003: 139)
  362. Loxospora elatina (Ach.) A. Massal. - Thomson (2003: 139)

  363. Maronea constans (Nyl.) Hepp - Thomson (2003: 139)

  364. Megalospora porphyritis (Tuck.) R. C. Harris - Bennett (2006: )

  365. Megaspora verrucosa (Ach.) Hafellner & Wirth - Thomson (1997: 443 as Pachyospora verrucosa), Thomson (2003: 140)

  366. Melanelixia albertana (Ahti) O. Blanco et al. - Thomson (2003: 141 as Melanelia albertana)
  367. Melanelixia fuliginosa (Fr. ex Duby) O. Blanco et al. - Thomson (1984: 303 as Parmelia glabratula), Bennett (2006: )
  368. Melanelixia subargentifera (Nyl.) O. Blanco et al. - Thomson (2003: 143 as Melanelia subargentifera)
  369. Melanelixia subaurifera (Nyl.) O. Blanco et al. - Thomson (1984: 316 as Parmelia subaurifera), Thomson (2003: 143 as Melanelia subaurifera)

  370. Melanohalea exasperata (De Not.) O. Blanco et al. - Thomson (2003: 142 as Melanelia exasperata)
  371. Melanohalea exasperatula (De Not.) O. Blanco et al. - Thomson (2003: 142 as Melanelia exasperatula)
  372. Melanohalea olivacea (L.) O. Blanco et al. - Thomson (1984: 306 as Parmelia olivacea), Thomson (2003: 142 as Melanelia olivacea)
  373. Melanohalea septentrionalis (Lynge) O. Blanco et al. - Thomson (1984: 311 as Parmelia septentrionalis), Thomson (2003: 143 as Melanelia septentrionalis)
  374. Melanohalea subolivacea (Nyl.) O. Blanco et al. - Thomson (2003: 144 as Melanelia subolivacea)

  375. Melaspilea arthonioides (Fée) Nyl. - Thomson (2003: 144)
  376. Melaspilea demissa (Tuck.) Zahlbr. - Thomson (2003: 145)

  377. Menegazzia terebrata (Hoffm.) A. Massal. - Thomson (2003: 145), Bennett & Wetmore (2004: 172 Critically Imperiled)

  378. Micarea denigrata (Fr.) Hedl. - Thomson (2003: 146)
  379. Micarea endocyanea (Tuck. ex Willey) R. C. Harris - Lay (2004: )
  380. Micarea melaena (Nyl.) Hedl. - Thomson (2003: 147)
  381. Micarea misella (Nyl.) Hedl. - Bennett (2006: )
  382. Micarea myriocarpa V. Wirth & Vezda ex Coppins - Thomson (2003: 147)
  383. Micarea peliocarpa (Anzi) Coppins & R. Sant. - Thomson (2003: 147)
  384. Micarea prasina Fr. - Thomson (2003: 148)

  385. Montanelia disjuncta (Erichsen) Divakar, A. Crespo, Wedin & Essl. - Thomson (2003: 140 as Melanelia disjuncta)
  386. Montanelia sorediata (Ach.) Divakar, A. Crespo, Wedin & Essl. - Thomson (1984: 312 as Parmelia sorediosa), Lay (2003: as Melanelia sorediata)
  387. Montanelia tominii (Oxner) Divakar, A. Crespo, Wedin & Essl. - Thomson (1984: 317 as Parmelia substygia), Thomson (2003: 144 as Melanelia tominii)

  388. Multiclavula mucida (Fr.) R. Petersen - Lay (2004: )
  389. Multiclavula vernalis (Schwein.) R. Petersen - Bennett (2006: )

  390. Mycobilimbia berengeriana (A. Massal.) Hafellner & V. Wirth - Thomson (1997: 331 as Lecidea berengeriana), Thomson (2003: 149)
  391. Mycobilimbia carneoalbida (Müll. Arg.) S. Ekman & Printzen - Thomson (1997: 110 as Bacidia sphaeroides), Thomson (2003: 39 as Bacidia carneoalbida)
  392. Mycobilimbia epixanthoides (Nyl.) Vitikainen et al. - Thomson (2003: 44 as Biatora epixanthoides)
  393. Mycobilimbia pilularis (Körb.) Hafellner & Türk - Brodo (1967: 212 as Bacidia sphaeroides), Thomson (2003: as )
  394. Mycobilimbia tetramera (de Not.) W. Brunnbauer - Thomson (1997: 422 as Mycobilimbia obscurata), Thomson (2003: 150)

  395. Mycoblastus sanguinarius (L.) Norman - Thomson (1997: 426), Thomson (2003: 150)

  396. Myelochroa aurulenta (Tuck.) Elix & Hale - Thomson (2003: 151)
  397. Myelochroa galbina (Ach.) Elix & Hale - Thomson (2003: 151)
  398. Myelochroa obsessa (Ach.) Elix & Hale - Thomson (2003: 151)

  399. Myriospora smaragdula (Wahlenb. in Ach.) K. Knudsen & B. Abbott - Thomson (1997: 34 as Acarospora smaragdula), Bennett (2006: as Acarospora smaragdula)

  400. Nephroma bellum (Spreng.) Tuck. - Thomson (1984: 278), Thomson (2003: 152), Bennett & Wetmore (2004: 172 Critically Imperiled)
  401. Nephroma helveticum Ach. var. helveticum - Thomson (1984: 280), Thomson (2003: 152)
  402. Nephroma parile (Ach.) Ach. - Thomson (1984: 282), Thomson (2003: 153)

  403. Normandina pulchella (Borrer) Nyl. - Lay (2004: )

  404. Ochrolechia androgyna (Hoffm.) Arnold - Thomson (1997: 430), Thomson (2003: 154)
  405. Ochrolechia arborea (Kreyer) Almb. - Thomson (2003: 154)
  406. Ochrolechia mexicana Vain. - Thomson (2003: 154)
  407. Ochrolechia pseudopallescens Brodo - Thomson (2003: 154)
  408. Ochrolechia trochophora (Vain.) Oshio var. pruinirosella Brodo - Brodo (1991: 763 Type), Kukwa (2009: 43)

  409. Ochrolechia trochophora (Vain.) Oshio var. trochophora - Thomson (2003: 155)

  410. Opegrapha vulgata Ach. - Lay (2004: )

  411. Pachypeltis invadens (Lynge) Søchting, Frödén & Arup - Thomson (2003: 56 as Caloplaca invadens)

  412. Pannaria conoplea (Ach.) Bory - Thomson (1984: 292), Thomson (2003: 157)
  413. Pannaria rubiginosa (Thunb.) Delise - Thomson (2003: 158)

  414. Parmelia fraudans (Nyl.) Nyl. - Thomson (2003: 158)
  415. Parmelia saxatilis (L.) Ach. - Thomson (1984: 310), Thomson (2003: 159)
  416. Parmelia squarrosa Hale - Thomson (1984: 313), Thomson (2003: 159)
  417. Parmelia sulcata Tayl. - Thomson (1984: 318), Thomson (2003: 159)

  418. Parmeliopsis ambigua (Wulf.) Nyl. - Thomson (1984: 325), Thomson (2003: 160)
  419. Parmeliopsis capitata R. C. Harris ex J. W. Hinds & P. L. Hinds - Thomson (2003: 160)
  420. Parmeliopsis hyperopta (Ach.) Arnold - Thomson (1984: 326), Thomson (2003: 160)

  421. Parmotrema arnoldii (Du Rietz) Hale - Thomson (2003: 161)
  422. Parmotrema crinitum (Ach.) Choisy - Thomson (2003: 162)
  423. Parmotrema hypotropum (Nyl.) Hale - Thomson (2003: 162)
  424. Parmotrema margaritatum (Hue) Hale - Thomson (2003: 162)
  425. Parmotrema perforatum (Jacq.) A. Massal. - Thomson (2003: 162), Bennett & Wetmore (2004: 173 Extinct)
  426. Parmotrema perlatum (Osbeck) Hale & Ahti - Thomson (2003: 161 as Parmotrema chinense), Bennett & Wetmore (2004: 172 as Parmotrema chinense Historical Occurrences)
  427. Parmotrema reticulatum (Taylor) M. Choisy - Thomson (2003: as Rimelia reticulatum)
  428. Parmotrema stuppeum (Taylor) Hale - Thomson (2003: ), Bennett & Wetmore (2004: 172 Historical Occurrences)
  429. Parmotrema subtinctorium (Zahlbr.) Elix - Thomson (2003: as Canomaculina subtinctoria)

  430. Parvoplaca tiroliensis Zahlbr. - Thomson (1997: 173 as Caloplaca tiroliensis), Thomson (2003: 58 as Caloplaca tiroliensis)

  431. Peltigera aphthosa (L.) Willd. - Thomson (1984: 329), Thomson (2003: 166)
  432. Peltigera canina (L.) Willd. - Thomson (2003: 166)
  433. Peltigera degenii Gyelnik - Thomson (2003: 166)
  434. Peltigera didactyla (With.) J. R. Laundon - Thomson (2003: 167)
  435. Peltigera evansiana Gyelnik - Brodo (1967: 212), Thomson (2003: 167)
  436. Peltigera horizontalis (Huds.) Baumg. - Brodo (1967: 212), Thomson (1984: 337), Thomson (2003: 167)
  437. Peltigera lepidophora (Nyl.) Vain. - Brodo (1967: 212), Thomson (1984: 338), Thomson (2003: 168)
  438. Peltigera leucophlebia (Nyl.) Gyelnik - Thomson (1984: 330 as Peltigera aphthosa var. leucophlebia)
  439. Peltigera malacea (Ach.) Funck. - Thomson (1984: 339), Thomson (2003: 168)
  440. Peltigera membranacea (Ach.) Nyl. - Thomson (2003: 168)
  441. Peltigera neckeri Hepp ex Müll. Arg. - Bennett (2006: )
  442. Peltigera polydactylon (Neck.) Hoffm. - Thomson (1984: 343), Thomson (2003: 169)
  443. Peltigera praetextata (Flörke ex Sommerf.) Zopf - Brodo (1967: 212)
  444. Peltigera rufescens (Weiss) Humb. - Brodo (1967: 212 as Peltigera canina var. rufescens), Thomson (2003: 169)
  445. Peltigera scabrosa Th. Fr. - Thomson (2003: 169), Bennett & Wetmore (2004: 172 Critically Imperiled)
  446. Peltigera venosa (L.) Hoffm. - Thomson (2003: 170), Bennett & Wetmore (2004: 173 Historical Occurrences)

  447. Pertusaria alpina Hepp ex Ahles - Thomson (2003: 171)
  448. Pertusaria consocians Dibben - Thomson (2003: 171)
  449. Pertusaria leioplaca (Ach.) DC. - Thomson (2003: 172)
  450. Pertusaria macounii (I. M. Lamb) Dibben - Thomson (2003: 172)
  451. Pertusaria neoscotica I. M. Lamb - Thomson (2003: 172)
  452. Pertusaria plittiana Erichsen - Thomson (2003: 173)
  453. Pertusaria pustulata (Ach.) Duby - Thomson (2003: 173)
  454. Pertusaria rubefacta Erichsen - Thomson (2003: 174)
  455. Pertusaria tetrathalamia (Fée) Nyl. - Thomson (2003: 174)
  456. Pertusaria xanthodes Müll. Arg. - Thomson (2003: 175)

  457. Phaeophyscia adiastola (Essl.) Essl. - Thomson (2003: 177)
  458. Phaeophyscia ciliata (Hoffm.) Moberg - Thomson (2003: 178)
  459. Phaeophyscia endococcina (Körb.) Moberg - Thomson (1984: 348), Thomson (2003: 178)
  460. Phaeophyscia erythrocardia (Tuck.) Essl. - Thomson (2003: 178)
  461. Phaeophyscia hirsuta (Mereschk.) Essl. - Thomson (2003: 177 as Phaeophyscia cernohorskyi)
  462. Phaeophyscia hirtella Essl. - Thomson (2003: 178)
  463. Phaeophyscia hispidula (Ach.) Essl. - Thomson (2003: 179), Thomson (2003: 179)
  464. Phaeophyscia kairamoi (Vain.) Moberg - Thomson (2003: 179)
  465. Phaeophyscia nigricans (Flörke) Moberg - Thomson (2003: 180)
  466. Phaeophyscia orbicularis (Neck.) Moberg - Thomson (2003: 180)
  467. Phaeophyscia pusilloides (Zahlbr.) Essl. - Thomson (2003: 180)
  468. Phaeophyscia rubropulchra (Degel.) Moberg - Thomson (2003: 180)
  469. Phaeophyscia sciastra (Ach.) Moberg - Thomson (1984: 349), Thomson (2003: 180)
  470. Phaeophyscia squarrosa Kashiw. - Thomson (2003: 179 as Phaeophyscia imbricata)

  471. Phlyctis argena (Ach.) Flot. - Thomson (2003: 181)

  472. Phylliscum demangeonii (Moug. & Mont.) Nyl. - Thomson (2003: 181)

  473. Physcia adscendens H. Olivier - Thomson (1984: 352), Thomson (2003: 183)
  474. Physcia aipolia (Ehrh. ex Humb.) Fürnr. - Thomson (1984: 353), Thomson (2003: 183)
  475. Physcia americana G. Merr. - Thomson (2003: 183)
  476. Physcia caesia (Hoffm.) Fürnr. - Thomson (1984: 354), Thomson (2003: 184)
  477. Physcia dubia (Hoffm.) Lettau - Thomson (1984: 355), Thomson (2003: 184)
  478. Physcia halei J. W. Thomson - Thomson (2003: 184)
  479. Physcia millegrana Degel. - Thomson (2003: 184)
  480. Physcia phaea (Tuck.) J. W. Thomson - Thomson (1984: 356), Thomson (2003: 185)
  481. Physcia stellaris (L.) Nyl. - Thomson (2003: 185)
  482. Physcia subtilis Degel. - Thomson (2003: 185)
  483. Physcia tenella (Scop.) DC. - Thomson (2003: 185), Bennett & Wetmore (2004: 173 Critically Imperiled)

  484. Physciella chloantha (Ach.) Essl. - Thomson (2003: 186)
  485. Physciella melanchra (Hue) Essl. - Thomson (2003: 186), Bennett & Wetmore (2004: 173 Imperiled)

  486. Physconia americana Essl. - Lay (2004: )
  487. Physconia detersa (Nyl.) Poelt - Thomson (1984: 359), Thomson (2003: 187)
  488. Physconia leucoleiptes (Tuck.) Essl. - Thomson (2003: 188)
  489. Physconia perisidiosa (Erichsen) Moberg - Thomson (2003: 188)

  490. Piccolia ochrophora (Nyl.) Hafellner - Thomson (2003: 224 as Strangospora ochrophora)

  491. Placidium arboreum (Schwein. ex Michener) Lendemer - Thomson (2003: 63 as Catapyrenium tuckermanii)
  492. Placidium lachneum (Ach.) Breuss - Thomson (1984: 217 as Dermatocarpon lachneum), Thomson (2003: ), Thomson (2003: 62 as Catapyrenium lachneum)
  493. Placidium lacinulatum (Ach.) Breuss - Thomson (2003: )
  494. Placidium rufescens (Ach.) Breuss - Thomson (2003: 63 as Catapyrenium rufescens)
  495. Placidium squamulosum (Ach.) Breuss - Brodo (1967: 211 as Dermatocarpon hepaticum), Thomson (1984: 215 as Dermatocarpon hepaticum), Thomson (2003: 63 as Catapyrenium squamulosum)

  496. Placopyrenium fuscellum (Turner) Gueidan & Cl. Roux - Thomson (2003: 243 as Verrucaria fuscella)

  497. Placynthiella dasaea (Stirt.) Tøberg - Bennett (2006: )
  498. Placynthiella icmalea (Ach.) Coppins & P. James - Thomson (2003: 189)
  499. Placynthiella oligotropha (J. R. Laundon) Coppins & P. James - Thomson (2003: 189)
  500. Placynthiella uliginosa (Schrad.) Coppins & James - Thomson (1997: 475), Thomson (2003: 189)

  501. Placynthium asperellum (Ach.) Trevisan - Thomson (1984: 365 as Placynthium aspratile), Thomson (2003: 190)
  502. Placynthium nigrum (Huds.) Gray - Thomson (1984: 366), Thomson (2003: 190)
  503. Placynthium stenophyllum (Tuck.) Fink - Thomson (2003: 190)

  504. Platismatia glauca (L.) W. L. Culb. & C. F. Culb. - Thomson (2003: 191)
  505. Platismatia tuckermanii (Oakes) W. L. Culb. & C. F. Culb. - Thomson (2003: 191)

  506. Pleopsidium chlorophanum (Wahlenb.) Zopf - Douglas (1974: 584 sub Acarospora chlorophana), Thomson (2003: 25 as Acarospora chlorophana)
  507. Pleopsidium flavum (Bellardi) Körb. - Bennett (2006: )

  508. Polycauliona candelaria (L.) Frödén, Arup, & Søchting - Thomson (1984: 483 as Xanthoria candelaria)
  509. Polycauliona polycarpa (Hoffm.) Frödén, Arup, & Søchting - Thomson (1984: 487 as Xanthoria polycarpa), Thomson (2003: 250 as Xanthoria polycarpa)
  510. Polysporina simplex (Taylor) Vezda - Thomson (1997: 486), Thomson (2003: 192)

  511. Porpidia albocaerulescens (Wulfen) Hertel & Knoph - Thomson (2003: 193)
  512. Porpidia contraponenda (Arnold) Knoph & Hertel - Bennett (2006: )
  513. Porpidia crustulata (Ach.) Hertel & Knoph - Thomson (2003: 193)
  514. Porpidia cinereoatra Gowan - Thomson (2003: 193 as Porpidia herteliana)
  515. Porpidia macrocarpa (DC.) Hertel & A. J. Schwab - Thomson (2003: 194)
  516. Porpidia speirea (Ach.) Kremp. - Thomson (1997: 497)
  517. Porpidia tuberculosa (Sm.) Hertel & Knoph - Lay (2004: )

  518. Protoblastenia rupestris (Scop.) Steiner - Thomson (1997: 503), Thomson (2003: 194)

  519. Protopannaria pezizoides (Weber) P. M. Jørg. & S. Ekman - Thomson (1984: 294 as Pannaria pezizoides), Thomson (2003: 157 as Pannaria pezizoides), Bennett & Wetmore (2004: 173 Historical Occurrences)

  520. Pseudevernia consocians (Vain.) Hale & W. L. Culb. - Thomson (2003: 195), Bennett & Wetmore (2004: 173 Critically Imperiled)

  521. Pseudocyphellaria crocata (L.) Vain. - Thomson (2003: 195), Bennett & Wetmore (2004: 173 Critically Imperiled)

  522. Pseudosagedia cestrensis (Tuck. ex E. Michener) R. C. Harris - Thomson (2003: 192 as Porina cestrensis)

  523. Psilolechia lucida (Ach.) M. Choisy - Thomson (2003: 196)

  524. Psora decipiens (Hedwig) Hoffm. - Brodo (1967: 212 as Lecidea decipiens), Thomson (1997: 507), Thomson (2003: 197)
  525. Psora pseudorussellii Timdal - Thomson (2003: 197)
  526. Psora russellii (Tuck.) A. Schneider - Brodo (1967: 212 as Lecidea russellii), Thomson (2003: 197)

  527. Psorotichia schaereri (A. Massal.) Arnold - Thomson (2003: 198)

  528. Psorula rufonigra (Tuck.) Gotth. Schneider - Thomson (1997: 515), Thomson (2003: 198)

  529. Punctelia bolliana (Müll. Arg.) Krog - Thomson (2003: 199)
  530. Punctelia hypoleucites (Nyl.) Krog - Thomson (2003: 199)
  531. Punctelia missouriensis G. Wilh. & Ladd - Thomson (2003: )
  532. Punctelia perreticulata (Räsänen) Wilhelm & Ladd - Thomson (2003: 199)
  533. Punctelia punctilla (Hale) Krog - Thomson (2003: 200)
  534. Punctelia rudecta (Ach.) Krog - Thomson (2003: 200)

  535. Puttea caesia (Fr.) M. Svensson & T. Sprib. - Bennett (2006: as Lecidea symmictella)

  536. Pycnothelia papillaria (Ehrh.) Duf. - Thomson (1984: 377), Thomson (2003: 201)

  537. Pyrenopsis phaeococca Tuck. - Thomson (2003: 201)

  538. Pyrenula laevigata (Pers.) Arnold - Lay (2004: )
  539. Pyrenula pseudobufonia (Rehm) R. C. Harris - Thomson (2003: 202)

  540. Pyxine sorediata (Ach.) Mont. - Thomson (2003: 203)

  541. Ramalina americana Hale - Thomson (2003: 204)
  542. Ramalina dilacerata (Hoffm.) Hoffm. - Thomson (2003: 204)
  543. Ramalina farinacea (L.) Ach. - Thomson (2003: 204), Bennett & Wetmore (2004: 173 Critically Imperiled)
  544. Ramalina intermedia (Del. ex Nyl.) Nyl. - Thomson (1984: 379), Thomson (2003: 204)
  545. Ramalina obtusata (Arnold) Bitter - Thomson (1984: 380), Thomson (2003: 205)
  546. Ramalina pollinaria (Westr.) Ach. - Thomson (2003: 205), Bennett & Wetmore (2004: 173 Historical Occurrences)
  547. Ramalina sinensis Jatta - Thomson (2003: 205)
  548. Ramalina unifolia J. W. Thomson - Thomson (1990: 341), Thomson (2003: 205), Bennett & Wetmore (2004: 173 Critically Imperiled)

  549. Ramboldia elabens (Fr.) Kantvilas & Elix - Thomson (2003: 202 as Pyrrhospora elabens)

  550. Rhizocarpon cinereovirens (Müll.Arg.) Vain. - Thomson (1997: 528), Thomson (2003: 206)
  551. Rhizocarpon concentricum (Davis) Beltr. - Thomson (1997: 529), Thomson (2003: 207)
  552. Rhizocarpon disporum (Nägeli ex Hepp) Müll. Arg. - Thomson (2003: 207)
  553. Rhizocarpon distinctum Th. Fr. - Thomson (2003: 207)
  554. Rhizocarpon eupetraeum (Nyl.) Arnold - Thomson (1997: 533), Thomson (2003: 208)
  555. Rhizocarpon geminatum Körb. - Thomson (1997: 537)
  556. Rhizocarpon grande (Flörke ex Flot.) Arnold - Thomson (1997: 539), Thomson (2003: 208)
  557. Rhizocarpon obscuratum auct. - Thomson (1997: 545), Thomson (2003: 208)
  558. Rhizocarpon oederi (Weber) Körb. - Thomson (2003: 208)
  559. Rhizocarpon petraeum (Wulfen) A. Massal. - Bennett (2006: )
  560. Rhizocarpon rubescens Th. Fr. sensu Fryday - Lay (2004: )
  561. Rhizocarpon tetramerum (Vain.) Vain. - Thomson (2003: 208)

  562. Rhizoplaca chrysoleuca (Sm.) Zopf - Thomson (1997: 554), Thomson (2003: 209)
  563. Rhizoplaca melanophthalma (Ramond) Leuck. & Poelt - Thomson (1997: 555), Thomson (2003: 210)
  564. Rhizoplaca subdiscrepans (Nyl.) R. Sant. - Thomson (2003: 210)

  565. Rinodina adirondackii H. Magn. - Bennett (2006: )
  566. Rinodina archaea (Ach.) Vain. - Thomson (1997: 560), Thomson (2003: 211)
  567. Rinodina ascociscana Tuck. - Thomson (2003: 212)
  568. Rinodina bischoffii (Hepp.) A. Massal. - Thomson (1997: 561), Thomson (2003: 212)
  569. Rinodina cana (Arnold) Arnold - Thomson (2003: 214 as Rinodina iowensis)
  570. Rinodina confragosa (Ach.) Körb. - Thomson (2003: 212)
  571. Rinodina degeliana Coppins - Thomson (2003: 212)
  572. Rinodina destituta H. Mayrhofer - Bennett (2006: as Rinodina vezdae)
  573. Rinodina efflorescens Malme - Thomson (2003: 213)
  574. Rinodina excrescens Vain. - Magnusson (1953: 192 as Rinodina marysvillensis var. thujae Type), Sheard (1987: 164 as Rinodina thujae), Sheard (1995: 119), Thomson (2003: 213)
  575. Rinodina freyi H. Magn. - Thomson (2003: 213 as Rinodina glauca)
  576. Rinodina oxydata (A. Massal.) A. Massal. - Thomson (2003: 214)
  577. Rinodina pachysperma H. Magn. - Magnusson (1953: 193 Type in WIS), Thomson (2003: 214), Sheard (2010: 156)
  578. Rinodina papillata H. Magn. - Magnusson (1953: 194 Type in U), Thomson (2003: 215), Sheard (2010: 159)
  579. Rinodina populicola H. Magn. - Magnusson (1953: 167 Type in Uppsala, Sweden UPS), Thomson (2003: 215), Sheard (2010: 167)
  580. Rinodina pyrina (Ach.) Arnold - Thomson (2003: 215)
  581. Rinodina sibirica H. Magn. - Thomson (2003: 214 erroneously as Rinodina granulans)
  582. Rinodina subminuta H. Magn. - Thomson (2003: 215)
  583. Rinodina tephraspis (Tuck.) Herre - Thomson (2003: 216)
  584. Rinodina turfacea (Wahlenb.) Körb. - Thomson (2003: 216)
  585. Romjularia lurida (Ach.) Timdal - Thomson (2003: 128 as Lecidea lurida)

  586. Rufoplaca arenaria (Pers.) Arup, Søchting & Frödén - Thomson (2003: 54 as Caloplaca arenaria)
  587. Rufoplaca oxfordensis (Fink) Arup, Søchting & Frödén - Thomson (2003: 57 as Caloplaca oxfordensis)
  588. Rusavskia elegans (Link) S. Y. Kondr. & Kärnefelt - Thomson (1984: 484 as Xanthoria elegans), Thomson (2003: 248 as Xanthoria elegans)
  589. Rusavskia sorediata (Vain.) S. Y. Kondr. & Kärnefelt - Thomson (1984: 487 as Xanthoria sorediata), Thomson (2003: 250 as Xanthoria sorediata)

  590. Sarcogyne clavus (DC. in Lam. & DC.) Kremp. - Brodo (1967: 212), Thomson (1997: 577), Thomson (2003: 216)
  591. Sarcogyne hypophaea (Ach.) A. Massal. - Thomson (2003: 217 erroneously as Sarcogyne privigna)
  592. Sarcogyne regularis Körb. - Brodo (1967: 212), Thomson (1997: 579), Thomson (2003: 217)

  593. Sclerophora nivea (Hoffm.) Tibell - Lay (2004: )

  594. Scoliciosporum chlorococcum (Stenh.) Vezda - Thomson (2003: 218)
  595. Scoliciosporum umbrinum (Ach.) Arnold - Thomson (1997: 585), Thomson (2003: 218)

  596. Scytinium dactylinum (Tuck.) Otálora, P. M. Jørg. & Wedin - Bennett & Bartkowiak (2013: 73 as Leptogium dactylinum)
  597. Scytinium intermedium (Arnold) Otálora, P. M. Jørg. & Wedin - Thomson (2003: 134 as Leptogium intermedium)
  598. Scytinium lichenoides (L.) Otálora, P. M. Jørg. & Wedin - Thomson (1984: 257 as Leptogium lichenoides), Thomson (2003: 134 as Leptogium lichenoides)
  599. Scytinium subtile (Schrad.) Otálora, P. M. Jørg. & Wedin - Thomson (1984: 259 as Leptogium minutissimum)
  600. Scytinium teretiusculum (Wallr.) Otálora, P. M. Jørg. & Wedin - Thomson (2003: 135 as Leptogium teretiusculum), Bennett & Wetmore (2004: 172 as Leptogium teretiusculum Critically Imperiled)

  601. Solitaria chrysophthalma (Degel.) Arup, Søchting & Frödén - Thomson (2003: 55 as Caloplaca chrysophthalma)

  602. Solorina saccata (L.) Ach. - Thomson (1984: 390), Thomson (2003: 218), Bennett & Wetmore (2004: 173 Historical Occurrences)

  603. Spilonema revertens Nyl. - Bennett (2006: )

  604. Squamulea galactophylla (Tuck.) Arup, Søchting & Frödén - Thomson (2003: 54 as Caloplaca galactophylla)
  605. Squamulea subsoluta (Nyl.) Arup, Søchting & Frödén - Bennett (2006: as Caloplaca subsoluta)
  606. Staurothele areolata (Ach.) Lettau - Brodo (1967: 211 as Staurothele clopima), Thomson (1997: 592), Thomson (2003: 220)
  607. Staurothele drummondii (Tuck.) Tuck. - Thomson (2003: 220)
  608. Staurothele fissa (Tayler) Zwackh. - Thomson (1997: 596), Thomson (2003: 220)
  609. Staurothele monicae (Zahlbr.) Wetmore - Bennett (2006: )

  610. Stereocaulon condensatum Hoffm. - Thomson (1984: 407), Thomson (2003: 222)
  611. Stereocaulon paschale (L.) Hoffm. - Thomson (1984: 418), Thomson (2003: 222)
  612. Stereocaulon saxatile H. Magn. - Thomson (1984: 423), Thomson (2003: 222)
  613. Stereocaulon tomentosum E. Fries - Thomson (1984: 428), Thomson (2003: 223)

  614. Sticta beauvoisii Delise - Thomson (1984: 434 falso sub Sticta weigelii), Thomson (2003: 223), Bennett & Wetmore (2004: 173 Critically Imperiled)
  615. Sticta fuliginosa (Hoffm.) Ach. - Lay (2004: )

  616. Stictis urceolatum (Ach.) Gilenstam - Thomson (2003: 95 as Conotrema urceolatum)

  617. Strangospora deplanata (Almq.) Poelt & Vezda - Thomson (2003: 224)
  618. Strangospora microhaema (Norman) R. Anderson - Thomson (2003: 224)
  619. Strangospora pinicola (A. Massal.) Körb. - Bennett (2006: )

  620. Strigula americana R. C. Harris - Thomson (2003: 225)
  621. Strigula stigmatella (Ach.) R. C. Harris - Thomson (2003: 225)
  622. Strigula submuriformis (R. C. Harris) R. C. Harris - Thomson (2003: 225)

  623. Teloschistes chrysophthalmus (L.) Th. Fr. - Thomson (2003: 226), Bennett & Wetmore (2004: 173 Historical Occurrences)

  624. Tephromela atra (Huds.) Hafellner - Thomson (1997: 633), Thomson (2003: 226)

  625. Thelenella pertusariella (Nyl.) Vain. - Lay (2004: )

  626. Thelidium fontigenum A. Massal. - Thomson (2003: 227 as Thelidium microbolum)

  627. Thelocarpon laureri (Flot.) Nyl. - Thomson (2003: 227)

  628. Thrombium epigaeum (Pers.) Wallr. - Thomson (1997: 610), Thomson (2003: 227)

  629. Thyrea confusa Henssen - Thomson (2003: 228)

  630. Toninia sedifolia (Scop.) Timdal - Thomson (1997: 614 as Toninia caeruleonigricans), Thomson (2003: 228)

  631. Trapelia coarctata (Turner ex Sm. & Sow.) M. Choisy - Thomson (1997: 621), Thomson (2003: 229)
  632. Trapelia glebulosa (Sm.) J. R. Laundon - Thomson (2003: 229 as Trapelia involuta)
  633. Trapelia obtegens (Th. Fr.) Hertel, Thomson (2003: 229)
  634. Trapelia placodioides Coppins & P. James - Thomson (2003: 230)

  635. Trapeliopsis flexuosa (Fr.) Coppins & James - Thomson (1997: 623), Thomson (2003: 230)
  636. Trapeliopsis gelatinosa (Flörke) Coppins & P. James - Thomson (2003: 231)
  637. Trapeliopsis granulosa (Hoffm.) Lumbsch - Thomson (1997: 624), Thomson (2003: 231)
  638. Trapeliopsis viridescens (Schrad.) Coppins & James - Thomson (1997: 625), Thomson (2003: 231)

  639. Tremolecia atrata (Ach.) Hertel - Thomson (1997: 627), Thomson (2003: 232)

  640. Trypethelium virens Tuck. ex E. Michener - Thomson (2003: 232)

  641. Tuckermanella fendleri (Nyl.) Essl. - Thomson (2003: 233 as Tuckermanopsis fendleri)

  642. Tuckermanopsis americana (Sprengel) Hale - Thomson (1984: 81 as Cetraria halei), Thomson (2003: 233)
  643. Tuckermanopsis ciliaris (Ach.) Gyelnik - Thomson (2003: 233)
  644. Tuckermanopsis orbata (Nyl.) M.-J. Lai - Thomson (2003: 234)
  645. Tuckermanopsis sepincola (Ehrh.) Hale - Thomson (1984: 94 as Cetraria sepincola), Thomson (2003: 234)

  646. Umbilicaria americana Poelt & T. H. Nash - Thomson (2003: 234)
  647. Umbilicaria deusta (L.) Baumg. - Lay (2004: )
  648. Umbilicaria lyngei Schol. - Llano (1950: as Agyrophora lyngei), Douglas (1974: 584 as Agyrophora lyngei)
  649. Umbilicaria mammulata (Ach.) Tuck. - Thomson (2003: 235)
  650. Umbilicaria muehlenbergii (Ach.) Tuck. - Thomson (1984: 26 as Actinogyra muhlenbergii), Thomson (2003: 234)
  651. Umbilicaria vellea (L.) Ach. - Thomson (1984: 460)

  652. Usnea angulata Ach. - Thomson (2003: 236), Bennett & Wetmore (2004: 173 Extinct)
  653. Usnea cavernosa Tuck. - Thomson (2003: 237)
  654. Usnea ceratina Ach. - Thomson (2003: 237), Bennett & Wetmore (2004: 173 Imperiled)
  655. Usnea filipendula Stirt. - Thomson (2003: 237)
  656. Usnea fulvoreagens (Räsänen) Räsänen - Lay (2004: )
  657. Usnea glabrata (Ach.) Vain. - Thomson (2003: 237)
  658. Usnea glabrescens (Nyl. ex Vain.) Vain. ex Räsänen - Thomson (2003: 238)
  659. Usnea halei P. Clerc - Thomson (2003: 238)
  660. Usnea hirta (L.) F. H. Wigg.- Thomson (1984: 466), Thomson (2003: 238)
  661. Usnea lapponica Vain. - Thomson (2003: 238)
  662. Usnea longissima Ach. - Thomson (2003: 239), Bennett & Wetmore (2004: 173 Extinct)
  663. Usnea mutabilis Stirt. - Thomson (2003: 239)
  664. Usnea rubicunda Stirt. - Thomson (2003: 239 as Usnea pensylvanica), Thomson (2003: 240), Bennett & Wetmore (2004: 173 Extinct)
  665. Usnea strigosa (Ach.) Eaton subsp. strigosa - Thomson (2003: 240)
  666. Usnea subfloridiana Stirt. - Thomson (1984: 469), Thomson (2003: 240)
  667. Usnea subfusca Stirt. - Thomson (2003: 240)
  668. Usnea substerilis Motyca - Thomson (1984: 470)
  669. Usnea trichodea Ach. - Thomson (2003: 241), Bennett & Wetmore (2004: 173 Imperiled)

  670. Usnocetraria oakesiana (Tuck.) M. J. Lai & C. J. Wei - Thomson (2003: 233 as Tuckermanopsis oakesiana)

  671. Vahliella leucophaea (Vahl) P. M. Jørg. - Thomson (2003: 104 as Fuscopannaria leucophaea), Bennett & Wetmore (2004: 172 as Fuscopannaria leucophaea Historical Occurrences)

  672. Varicellaria velata (Turner) Schmitt & Lumbsch - Thomson (2003: 175 as Pertusaria velata)

  673. Variolaria ophthalmiza Nyl. - Thomson (2003: 173 as Pertusaria ophthalmiza)
  674. Variolaria pustulata (Brodo & W. L. Culb.) Lendemer, Hodkinson & R. C. Harris - Thomson (2003: 139 as Loxospora pustulata)
  675. Variolaria trachythallina (Erichsen) Lendemer, Hodkinson & R. C. Harris - Thomson (2003: 174 as Pertusaria trachythallina)

  676. Verrucaria aethiobola Wahlenb. - Thomson (1997: 632), Thomson (2003: 242)
  677. Verrucaria calkinsiana Servít - Brodo (1967: 211), Thomson (2003: 242)
  678. Verrucaria fayettensis Servít - Thomson (2003: )
  679. Verrucaria glaucovirens Grummann - Thomson (2003: 243)
  680. Verrucaria margacea (Wahlenb. in Ach.) Wahlenb. - Thomson (1997: 639), Thomson (2003: 243)
  681. Verrucaria muralis Ach. - Thomson (1997: 641), Thomson (2003: 244)
  682. Verrucaria nigrescens Pers. - Brodo (1967: 211), Thomson (1997: 642), Thomson (2003: 244)
  683. Verrucaria nigrescentoidea Fink - Thomson (2003: 244)
  684. Verrucaria pseudonigrescens Servít - Thomson (2003: 244)
  685. Verrucaria rupestris Schrad. - Brodo (1967: 211), Thomson (1997: 643)
  686. Verrucaria viridigrana Breuss - Lay (2004: )
  687. Verrucaria viridula (Schrad.) Ach. - Thomson (2003: 244)

  688. Vulpicida pinastri (Scop.) J.-E. Mattsson & M.-J. Lai - Thomson (1984: 93 as Cetraria pinastri), Thomson (2003: 245)

  689. Xanthocarpia feracissima (H. Magn.) Frödén, Arup & Søchting - Magnusson (1953: 189 as Caloplaca feracissima Type), Thomson (2003: 55 as Caloplaca feracissima)
  690. Xanthocarpia lactea (A. Massal.) A. Massal. - Thomson (2003: 57 as Caloplaca lactea)

  691. Xanthomendoza fallax (Hepp in Arnold) Søchting, Kärnefelt & S. Kondr. - Thomson (1984: 486 as Xanthoria fallax), Thomson (2003: 249 as Xanthoria fallax)
  692. Xanthomendoza fulva (Hoffm.) Söchting, Kärnefelt & S. Kondr. - Thomson (2003: 249 as Xanthoria fulva)
  693. Xanthomendoza hasseana (Räsänen) Søchting, Kärnefelt & S. Y. Kondr. - Thomson (2003: 249 as Xanthoria hasseana)
  694. Xanthomendoza ulophyllodes (Räsänen) Söchting, Kärnefelt & S. Kondr. - Thomson (2003: 250 as Xanthoria ulophyllodes)

  695. Xanthoparmelia angustiphylla (Gyeln.) Hale - Thomson (2003: 246)
  696. Xanthoparmelia conspersa (Ehrh. ex Ach.) Hale - Thomson (2003: 246)
  697. Xanthoparmelia cumberlandia (Gyeln.) Hale - Thomson (2003: 246)
  698. Xanthoparmelia dierythra (Hale) Hale - Thomson (2003: 247)
  699. Xanthoparmelia hypofusca (Gyeln.) B. P. Hodk. & Lendemer - Thomson (2003: 248 erroneously as Xanthoparmelia tasmanica)
  700. Xanthoparmelia norhypopsila Hale - Bennett (2006: )
  701. Xanthoparmelia plittii (Gyeln.) Hale - Thomson (2003: 247)
  702. Xanthoparmelia stenophylla (Ach.) Ahti & D. Hawksw. - Thomson (2003: 247 as Xanthoparmelia somloensis)
  703. Xanthoparmelia subramigera (Gyeln.) Hale - Thomson (2003: 247)
  704. Xanthoparmelia viriduloumbrina (Gyeln.) Lendemer - Thomson (1984: 480 erroneously as Xanthoparmelia taractica)

  705. Xylographa opegraphella Nyl. - Bennett (2006: )

  706. Xylopsora friesii (Ach.) Bendiksby & Timdal - Thomson (1997: 247 as Hypocenomyce friesii), Thomson (2003: 109 as Hypocenomyce friesii)

  707. Zwackhia prosodea (Afzel.) Ertz - Thomson (2003: 156 as Opegrapha prosodea)
  708. Zwackhia viridis (Ach.) Poetsch & Schied. - Thomson (2003: 156 as Opegrapha viridis)