Arthonia radiata

Ascomycota › Arthoniomycetes › Arthoniales › Arthoniaceae › Arthonia

Description

A thin, smooth whitish or pale-grey crust. Black fruiting bodies vary from rounded spots to short, branched lines or small star-like clusters, without a conspicuous raised rim.

Source: ITALIC — Arthonia radiata

Chemistry

Thallus: K−, C−, KC−, P−, UV−. No characteristic lichen substances are reported. Some internal pigmented tissues show a pale-green K reaction in section.

Source: ITALIC — Arthonia radiata

Habitat and Substrate

Occurs on bark in woodland, parks and other settled landscapes, including moderately polluted sites.

Source: ITALIC — Arthonia radiata

Similar Species

Compare Naevia punctiformis and other small Arthonia species. The star-like appearance is useful, but microscopic confirmation may be necessary.

Sources: ITALIC; BLS identification revision

How to Identify

Use the Arthonia key; check the photobiont, fruiting-body structure and spore septation.

Source: BLS identification revision

Important Links

ITALIC — description, chemistry and images

British Lichen Society — species account and British distribution

GBIF — taxonomy and global occurrence records

AFL — species account and photographs

Identification Bibliography

Cannon, P., et al. (2020). Arthoniales: Arthoniaceae. Revisions of British and Irish Lichens, 1, 3–48.

Nimis, P. L., et al. ITALIC: The Information System on Italian Lichens. Online account: Arthonia radiata.

For identification, use the relevant key and compare the microscopic characters and chemical reactions. Photographs alone may be insufficient for closely similar crustose species.