Phlyctis petraea
R.C. Harris, Muscavitch, Ladd & Lendemer
Eggshell rock blaze
G5SecureGlobal Rank
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.1013213
Element CodeNLT00220A0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryFungus
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomFungi
PhylumAscomycota
ClassAscomycetes
OrderOstropales
FamilyPhlyctidaceae
GenusPhlyctis
Concept ReferenceMuscavitch, M.M., J.C. Lendemer, and R.C. Harris. 2017. A review of the lichen genus Phlyctis in North America (Phlyctidaceae) including the description of a new widespread saxicolous species from eastern North America. The Bryologist 120(4): 388-417.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-08-25
Change Date2025-08-25
Edition Date2025-08-25
Edition AuthorsJ.L. Allen (2025)
Threat ImpactUnknown
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences> 300
Rank ReasonsPhlyctis petraea is a crustose, green-algal lichen that occurs on boulders and rock outcrops in forests across much of eastern North America in the eastern United States and adjacent areas of Canada. It is most abundant in the Appalachian and Ozark mountains. Because of its widespread distribution, abundance, and the lack of documented threats, it is considered secure.
Range Extent CommentsPhlyctis petraea occurs in eastern North America. In Canada it is found in southern Ontario, and in the United States it occurs from Maine to Georgia west to Oklahama and Missouri (Muscavitch et al. 2017, GBIF 2025). The species is most abundant in the Appalachian and Ozark Mountains of the eastern United States. Range extent was estimated using herbarium specimens collected between 1985 and 2025 (GBIF 2025, RARECAT 2025).
Occurrences CommentsBy applying a 1 km separation distance to herbarium records documented between 1985 and 2025, it is estimated that there are >300 occurrences rangewide (GBIF 2025, RARECAT 2025).
Threat Impact CommentsAlthough threats are not widely documented, Phlyctis petraea is potentially threatened by development, gas and oil extraction, and other threats in some places. However, their overall impact is likely negligible given the species' broad range, large number of occurrences, and affinity for typically abundant habitats.
Ecology & Habitat
Description
Phlyctis petraea is a crustose green algal lichen distinguished from similar species by the absence of an uppder cortex, presence of schizidia, absence of apothecia, and production of norstictic acid and occasionally stictic acid (Muscavitch et al. 2017).
Terrestrial HabitatsForest/WoodlandForest - HardwoodForest - ConiferForest - Mixed
Other Nations (2)
CanadaNU
| Province | Rank | Native |
|---|
| Ontario | SU | Yes |
United StatesNNR
| Province | Rank | Native |
|---|
| Pennsylvania | SNR | Yes |
| Kentucky | S5 | Yes |
| Georgia | SNR | Yes |
Roadless Areas (6)
Kentucky (1)
| Area | Forest | Acres |
|---|
| Wolfpen | Daniel Boone National Forest | 2,835 |
Virginia (1)
| Area | Forest | Acres |
|---|
| Hoop Hole | Jefferson National Forest | 4,652 |
References (4)
- Esslinger, T. L. 2018. A cumulative checklist for the lichen-forming, lichenicolous and allied fungi of the continental United States and Canada, Version 22. Opuscula Philolichenum 17:6-268. [http://sweetgum.nybg.org/philolichenum/]
- Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
- Muscavitch, M.M., J.C. Lendemer, and R.C. Harris. 2017. A review of the lichen genus Phlyctis in North America (Phlyctidaceae) including the description of a new widespread saxicolous species from eastern North America. The Bryologist 120(4): 388-417.
- <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>