For more information see the Supplementary Notes for the Taxon Dictionary, which explains the names and synonyms, and these Instructions on how to use the online Taxon Dictionary which includes details of the Conservation Evaluation codes.
| Count | Name | Authority | Is Current Name? | Current Taxon Name | Synonyms | BLS Number | Comments | Conservation Evaluation | Group | Account & Map |
|---|---|---|---|---|---|---|---|---|---|---|
| 5041 | Lichen sinuosus | Sm. (1809) | No | Hypotrachyna sinuosa | 1017 | LC Sc IR | ||||
| 5042 | Lichen sparassus | (Ach.) Sm. | No | Cladonia squamosa var. squamosa | 2365 | LC | ||||
| 5043 | Lichen speireus | auct. brit. | No | Rhizocarpon umbilicatum | 1279 | LC | ||||
| 5044 | Lichen sphaeroides | Dicks. (1785) | No | Mycobilimbia sphaeroides | 320 | LC L* | ||||
| 5045 | Lichen spongiosus | Sm. (1804), non Scop. (1772) | No | Solorina spongiosa | 1331 | LC NS | ||||
| 5046 | Lichen spongiosus | With., non Scop. | No | Sticta canariensis | 1365 | VU D2 NR P Sc WaL IR | ||||
| 5047 | Lichen spurius | Ach. | No | Peltigera didactyla | 1053 | LC | ||||
| 5048 | Lichen squamatus | Dicks (1790) non Vill. (1789) | No | Thalloidima squamatum | 2874 | Material seen by Dickson from "Scotia" may not be this species | NE NR | |||
| 5049 | Lichen squamulosus | sensu Sm. (1809), ? non Schrad. (1797) | No | Acarospora fuscata | 10 | LC | ||||
| 5050 | Lichen stellaris | auct. brit. p.m.p. | No | Physcia aipolia | 1113 | LC | ||||
| 5051 | Lichen stellaris | L. | No | Physcia stellaris | 1119 | LC | ||||
| 5052 | Lichen stictoceros | Sm. (1804) | No | Evernia prunastri | 511 | LC | ||||
| 5053 | Lichen subfuscus | L. | No | Lecanora chlarotera s. lat. | 639 | See Lecanora subfusca | LC | |||
| 5054 | Lichen subulatus | L. | No | Cladonia subulata | 422 | LC | ||||
| 5055 | Lichen sulphureus | Hoffm. | No | Lecanora sulphurea | 783 | LC | ||||
| 5056 | Lichen tartareus | L. | No | Ochrolechia tartarea | 928 | LC | ||||
| 5057 | Lichen terrestris | Sm. (1807) | No | Thrombium epigaeum | 1414 | LC NS | ||||
| 5058 | Lichen tessellatus | Sm. | No | Verrucaria sp. | Verrucaria sp. | |||||
| 5059 | Lichen thelostomus | (Ach. ex J. Harriman) Sm. (1810) | No | Pyrenocarpon thelostomum | 1813 | DD NR | ||||
| 5060 | Lichen tigillaris | Ach. | No | Calicium tigillare | 476 | NT NR Sc | ||||
| 5061 | Lichen torrefactus | Lightf. | No | Umbilicaria torrefacta | 1455 | LC | ||||
| 5062 | Lichen trabinellus | sensu Sm., non (Ach.) Sm. | No | Chaenotheca phaeocephala | 347 | CR B NR P Wa | ||||
| 5063 | Lichen tricolor | With. | No | ? Opegrapha sp. or Hysterium pulicare Pers. {F} | ||||||
| 5064 | Lichen tuberculosus | Sm. (1807), non Hoffm. (1784) | No | Circinaria tuberculosa | 1851 | Ex | ||||
| 5065 | Lichen tumidulus | Sm. | No | Porpidinia tumidula | 1429 | Ex | ||||
| 5066 | Lichen turneri | Sm. | No | Ochrolechia turneri | 929 | LC | ||||
| 5067 | Lichen uncialis | auct. brit. p.m.p. | No | Cladonia uncialis subsp. biuncialis | 426 | LC | ||||
| 5068 | Lichen uncialis | L. | No | Cladonia uncialis subsp. uncialis | 1594 | NT NS Sc | ||||
| 5069 | Lichen velleus | sensu Huds., non L. | No | Umbilicaria vellea | Umbilicaria vellea (L.) Hoffm., incorrectly reported from the British Isles | |||||
| 5070 | Lichen venosus | L. | No | Peltigera venosa | 1054 | VU C1 NS P Eng Sc Wa |