Boulder Lichen vs Concentric Boulder Lichen

Porpidia tuberculosa compared with Porpidia crustulata

Key Differences

• Boulder Lichen is Least Concern while Concentric Boulder Lichen is Vulnerable.

Taxonomic Classification

Rank	Boulder Lichen	Concentric Boulder Lichen
Kingdom same	Fungi (真菌界)	Fungi (真菌界)
Phylum same	Ascomycota (子囊菌门)	Ascomycota (子囊菌门)
Class same	Lecanoromycetes (茶漬綱)	Lecanoromycetes (茶漬綱)
Order same	Lecideales (网衣目)	Lecideales (网衣目)
Family same	Lecideaceae	Lecideaceae
Genus same	Porpidia	Porpidia
Species	Porpidia tuberculosa	Porpidia crustulata

Evolutionary Relationship

Boulder Lichen and Concentric Boulder Lichen share a common ancestor at the Genus level: Porpidia.

Conservation Status

Boulder Lichen

LC — Least Concern

Concentric Boulder Lichen

VU — Vulnerable

Physical Characteristics

Attribute	Boulder Lichen	Concentric Boulder Lichen
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Boulder Lichen

Habitat

Native to Europe and North America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, Portugal, Sweden, and United States.

Concentric Boulder Lichen

Habitat

Native to Europe and North America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, Portugal, Sweden, and United States. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Boulder Lichen

The Boulder Lichen (Porpidia tuberculosa) is a species in the genus Porpidia. It is currently classified as Least Concern on the IUCN Red List. Native to Europe and North America, inhabiting ecosystems characteristic of the region.

Concentric Boulder Lichen

<em>Porpidia crustulata</em>, commonly known as the Concentric Boulder Lichen, is a crustose lichen in the family Porpidiaceae formed through a symbiotic relationship between a fungal partner (mycobiont) and photosynthetic green algae (photobiont). Like all crustose lichens, it grows tightly appressed to its substrate—typically siliceous or acidic rock surfaces including boulders, cliff faces, and pebbles in open, well-lit habitats—forming thin, grayish to pale thalli marked by scattered black apothecia (reproductive discs). <em>Porpidia crustulata</em> derives nutrition entirely through photosynthesis conducted by its algal partner, requiring no external organic food source. The species has been documented in Denmark, Norway, Portugal, Sweden, and the United States, suggesting a broad boreal to temperate distribution across the Northern Hemisphere. It is currently classified as Vulnerable by the IUCN, indicating significant conservation concern, likely linked to threats including air pollution, acidification, quarrying of rocky habitats, and changes in land use that reduce the availability of suitable substrates. Crustose lichens are typically slow-growing, long-lived organisms with limited capacity for rapid range shifts in response to environmental change. Biological traits such as individual lifespan, growth rates, and reproductive output remain poorly documented at the population level.

Shared Countries

Both species can be found in 5 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇵🇹 Portugal 🇸🇪 Sweden 🇺🇸 United States