Lichens of Florida's Journal

I'm reposting this with some new resources. Hopefully this is helpful to tackle lichen ID!

I highly recommend using these resources instead of relying on the iNaturalist suggested identifications. The iNaturalist "computer vision" is trained incorrectly for many lichen taxa.

Field Oriented Keys to the Florida Lichens revised April 2022, by Roger Rosentreter, Ann DeBolt & Laurel Kaminsky
Start here. This only includes Florida macrolichens and a few easily distinguished crustose genera.

Brodo, I. M., Sharnoff, S. D., & Sharnoff, S. (2001). Lichens of north America. Yale University Press.
An expensive but beautiful and well-illustrated book. Very helpful. It's one of my favorite books on any taxa.

Brodo, I. M. (2016). Keys to lichens of North America: revised and expanded. Yale University Press.
The keys in Brodo et al. (2001) are not comprehensive; many more species are included in the Brodo (2016) keys. It's not illustrated, so it helps to use it in conjunction with Brodo et al (2001) and the websites below.

Georgia Lichen Atlas by Malcolm Hodges & Sean Beeching
This includes many Florida species, is well-illustrated, and includes sections on similar species, natural history information, range maps, etc.

Lichens of Subtropical Florida, Seavy Guide
Includes photos of South Florida species, many of which are not illustrated anywhere else. 459 of the 550+ species on the Everglades National Park Lichen Project checklist are included.
Seavy also includes pages that describe how to identify common South Florida species.

Lichen Portal
Includes interactive mapping of herbarium specimens plus descriptions. Very detailed and includes all species. Some herbarium specimens may be incorrectly identified, so interpret the maps carefully.

Stephen Sharnoff's Lichen Photos 1,275 species throughout North America.

Pictures of Tropical Lichens has a worldwide focus, but it includes photos of some species not included elsewhere.

Ways of Enlichenment
Includes photos of many species

Lichens of North Carolina
Another good resource.

Harris, R. C. (1995). More Florida Lichens, including the 10¢ Tour of the Pyrenolichens. The New York Botanical Garden.
This is a very useful key, though it's not online and I can't find it for sale.

Lendemer, J.C. and N. Noell. 2018. Delmarva Lichens: An Illustrated Manual. Memoirs of the Torrey Botanical Society, 28:1-386. (purchase here). I don't have this book yet, but it could be useful for the eastern coastal plain.

Cladonia: a field guide by N.H. Hodgetts. This 1992 guide is intended for the UK and is missing several southeastern US species, but it has a visual glossary and useful figures that can help with Cladonia ID.

The lichens of Fakahatchee Strand Preserve State Park, Florida
(link with the photo appendices)
Lucking, R., Seavey, F., Common, R.S., Beeching, S.Q., Breuss, O., Buck, W.R., Crane, L., Hodges, M., Hodkinson, B.P., Lay, E. and Lendemer, J.C., 2011. The lichens of Fakahatchee Strand Preserve State Park, Florida: proceedings from the 18th tuckerman workshop. Bulletin of the Florida Museum of Natural History. 49 (4): 127-186., 49(4), pp.127-186.
Contains descriptions of cryptic species

Seavey, F., Seavey, J., Gagnon, J., Guccion, J., Kaminsky, B., Pearson, J., Podaril, A. and Randall, B., 2017. The lichens of Dagny Johnson Key Largo Hammock Botanical State Park, Key Largo, Florida, USA. Bulletin of the Florida Museum of Natural History, 53(5), pp.201-268.
Contains photos of uncommon species from the keys.

Detailed article on Trypetheliaceae
Aptroot, A., & Luecking, R. (2016). A revisionary synopsis of the Trypetheliaceae (Ascomycota: Trypetheliales). The Lichenologist, 48(6), 763-982.

A world key to the species of Anthracothecium and Pyrenula
Aptroot, A. (2012). A world key to the species of Anthracothecium and Pyrenula. The Lichenologist, 44(1), 5-53.

Dombrowski, A. (2022). Systematics of the Letrouitiaceae (Lichen-forming Ascomycota): an overlooked tropical family.

The following species either do not occur in Florida, they are uncommon in Florida, or I'm unsure of their status. However, these species totaled over 1600 observations, which shows there is a serious problem with iNaturalist suggesting non-FL species and users selecting them. In some cases, the CV may be trained incorrectly.
() = number of FL observations in iNaturalist
Cladonia coniocraea - Common Powderhorn (139)
Flavoparmelia caperata - Common Greenshield Lichen (was 600, currently 241 after making an effort to sort these)
Flavopunctelia flaventior - Speckled Greenshield (48)
Flavopunctelia soredica - Powder-edge Speckled Greenshield (67)
Lecanora thysanophora - Mapledust Lichen (45)
Parmelia sulcata - Shield Lichen (52)
Phlyctis argena - Whitewash Lichen (64)
Ramalina farinacea - Farinose Cartilage Lichen (119)
Usnea florida - Florida Beard Lichen (12)
Usnea hirta - Bristly Beard Lichen (was 500+, now 0)

One of the most commonly identified lichens in Florida used to be Usnea hirta, which is a northern species. I worked through 400+ incorrect identifications, and most were Usnea strigosa or Ramalina.

Another commonly misidentified lichen is Common Greenshield Lichen (Flavoparmelia caperata). This species does not occur in Florida, yet there are currently over 500 observations identified as this in Florida. It's the fourth most common species identified in Florida on iNat! Many green lichens are identified by iNat CV as Flavoparmelia, which is common in regions outside of Florida.

Photo © Don Hunter, Banks Co., Ga., 22 Sept. 2017 from Georgia Lichen Atlas

Entry from Georgia Lichen Atlas
Entry from Lichen Portal which has a few mis-identified herbarium specimens from Florida.

Many of these are Parmotrema, which have wide lobes, apothecia, soredia, and/or isidia, and the edges are not attached or adnate against bark. Some with smaller lobes may be Parmeliopsis, Hypotrachyna, Myelochroa, Canoparmelia, or members of Physciaceae. Unfortunately most of the observations are poor photos taken at distance that cannot be identified to any genus let alone species.

Some similar taxa that occur in Florida:
Parmotrema tinctorum

Photo © Don Hunter, Berrien Co., Ga., 8 March 2014 from Georgia Lichen Atlas

Canoparmelia caroliniana

Photo © Don Hunter, Pike Co., Ga., 13 October 2015 from Georgia Lichen Atlas

Parmeliopsis subambigua

Photo © Don Hunter, Troup Co., Ga., 11 May 2014 from Georgia Lichen Atlas

Hypotrachyna pustulifera

Photo © Don Hunter, Berrien Co., Ga., 8 Mar. 2014 from Georgia Lichen Atlas

Physcia americana

Photo © Don Hunter, Tift Co., Ga., 9 Mar. 2014 from Georgia Lichen Atlas

There are numerous great resources for identifying lichens, and users will need to consult these instead of relying on the iNaturalist suggested identifications. The iNaturalist "computer vision" is trained incorrectly for many taxa, so don't trust it.

Field Oriented Keys to the Florida Lichens revised April 2022, by Roger Rosentreter, Ann DeBolt & Laurel Kaminsky
Start here. This only includes Florida macrolichens and a few easily distinguished crustose genera.

Brodo, I. M., Sharnoff, S. D., & Sharnoff, S. (2001). Lichens of north America. Yale University Press.
An expensive but beautiful and well-illustrated book. Very helpful. It's one of my favorite books on any taxa.

Brodo, I. M. (2016). Keys to lichens of North America: revised and expanded. Yale University Press.
The keys in Brodo et al. (2001) are not comprehensive; many more species are included in the Brodo (2016) keys. It's not illustrated, so it helps to use it in conjunction with Brodo et al (2001) and the websites below.

Georgia Lichen Atlas by Malcolm Hodges & Sean Beeching
This includes many Florida species, is well-illustrated, and includes sections on similar species, natural history information, range maps, etc.

Lichens of Subtropical Florida, Seavy Guide
Includes photos of South Florida species, many of which are not illustrated anywhere else. 459 of the 550+ species on the Everglades National Park Lichen Project checklist are included.
Seavy also includes pages that describe how to identify common South Florida species.

Lichen Portal
Includes interactive mapping of herbarium specimens plus descriptions. Very detailed and includes all species. Some herbarium specimens may be incorrectly identified.

Ways of Enlichenment
Includes photos of many species

Lichens of North Carolina
Another good resource.

Detailed article on Trypetheliaceae
Aptroot, A., & Luecking, R. (2016). A revisionary synopsis of the Trypetheliaceae (Ascomycota: Trypetheliales). The Lichenologist, 48(6), 763-982.

Thanks to @knotwood for pointing out these additional resources:
The lichens of Fakahatchee Strand Preserve State Park, Florida
Lucking, R., Seavey, F., Common, R.S., Beeching, S.Q., Breuss, O., Buck, W.R., Crane, L., Hodges, M., Hodkinson, B.P., Lay, E. and Lendemer, J.C., 2011. The lichens of Fakahatchee Strand Preserve State Park, Florida: proceedings from the 18th tuckerman workshop. Bulletin of the Florida Museum of Natural History. 49 (4): 127-186., 49(4), pp.127-186.
Contains descriptions of cryptic species

A world key to the species of Anthracothecium and Pyrenula
Aptroot, A. (2012). A world key to the species of Anthracothecium and Pyrenula. The Lichenologist, 44(1), 5-53.