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 |
|---|---|---|---|---|---|---|---|---|---|---|
| 4321 | Lecidea sapinea f. aeruginosa | (Borrer) Zahlbr. | No | Trapeliopsis flexuosa | 692 | LC | ||||
| 4322 | Lecidea sarcogyniza | Nyl. | No | Lecidea diducens | 715 | LC NS | ||||
| 4323 | Lecidea sarcogynoides | Körb. (1855) | Yes | Lecidea sarcogynoides | 769 | VU D2 NR | Lecidea sarcogynoides | |||
| 4324 | Lecidea saxatilis | (Schaer.) Hepp (1853) | No | Sclerococcum saxatile | 2050 | NE NR | LF | |||
| 4325 | Lecidea scabra | Taylor | No | Lecidella scabra | 802 | LC | ||||
| 4326 | Lecidea scabra f. meiococca | Nyl. | No | Lecidella meiococca | 800 | LC NS | ||||
| 4327 | Lecidea scabrosa | Ach. | No | Epilichen scabrosus | 510 | LC NS M* | LF | |||
| 4328 | Lecidea scabrosa | auct. brit. p.p., non Ach. | No | Lecidella asema | 804 | LC | ||||
| 4329 | Lecidea scabrosa | auct. brit. p.p., non Ach. | No | Lecidella elaeochroma f. elaeochroma | 797 | LC | ||||
| 4330 | Lecidea scalaris | (Ach. ex Lilj.) Ach. (1803) | No | Hypocenomyce scalaris | 578 | LC | ||||
| 4331 | Lecidea scapanaria | Carrington | No | Dactylospora scapanaria | Dactylospora scapanaria (Carrington) D. Hawksw. | F | ||||
| 4332 | Lecidea scotinodes | Nyl. (1873) | No | Catillaria scotinodes | 770 | LC NS | ||||
| 4333 | Lecidea scutellata | Walt. Watson | No | Porpidia crustulata | 564 | LC | ||||
| 4334 | Lecidea scutulata | Stirt. | No | Amygdalaria consentiens | 563 | LC NS | ||||
| 4335 | Lecidea segregans | Nyl. | No | Miriquidica pycnocarpa f. pycnocarpa | 766 | LC NS | ||||
| 4336 | Lecidea semipallens | Nyl. | No | Brianaria bauschiana | 873 | LC | ||||
| 4337 | Lecidea siderolithica | Müll. Arg. (1872) | Yes | Lecidea siderolithica | Lecidea nigrogrisea | 753 | DD NR | Lecidea siderolithica | ||
| 4338 | Lecidea silacea | Ach. (1803) | Yes | Lecidea silacea | 772 | LC NS | Lecidea silacea | |||
| 4339 | Lecidea simplex | (Davies) Hook. (1833) | No | Acarospora privigna | 1167 | LC | ||||
| 4340 | Lecidea simplicior | (Ach. ex Nyl.) Lindsay (1867) | No | Gilbertaria contristans | 309 | LC NS | ||||
| 4341 | Lecidea sincerula | Nyl. (1876) | No | Tremolecia atrata | 1438 | LC | ||||
| 4342 | Lecidea socialis | (Körb.) Cromb. | No | Schadonia fecunda | 1310 | VU D2 NR Sc | ||||
| 4343 | Lecidea sorediza | Nyl. | No | Porpidia tuberculosa | 572 | LC | ||||
| 4344 | Lecidea soredizodes | (Lamy ex Nyl.) Lindau (1913) | No | Porpidia soredizodes | 1690 | LC | ||||
| 4345 | Lecidea speirea | (Ach.) Ach. | No | Porpidia speirea | 774 | LC | ||||
| 4346 | Lecidea speirea | auct. brit. p.p. | No | Rhizocarpon umbilicatum | 1279 | LC | ||||
| 4347 | Lecidea sphaeroides | auct. brit. | No | various lecidioid lichens with pale, biatorine apothecia | ||||||
| 4348 | Lecidea spodiza | Nyl. | No | Micarea denigrata | 877 | LC | ||||
| 4349 | Lecidea spododes | Nyl. | No | Micarea nitschkeana | 885 | LC | ||||
| 4350 | Lecidea sporadiza | Stirt. (1874) | No | Trapeliopsis flexuosa | 692 | LC |