Cetradonia J.-C. Wei & Ahti (=Gymnoderma Nyl.) (Cetradoniaceae)

Cetradonia is represented by a single species, endemic to the southern Appalachians: C. linearis (Fed E, S2 G2). The species was formerly referred to Gymnoderma s.l. and listed under its combination in that genus: Gymnoderma lineare (Yoshimura & Sharp 1968).

Basic lichen habits

Crustose lichen form
Crustose (Photo: Krings)
Squamulose lichen form
Squamulose (Photo: Krings)
Foliose lichen form
Foliose (Photo: Krings)
Fruticose lichen form
Fruticose (Photo: Krings)
Crustose Squamulose Foliose Fruticose

Federally listed taxon—
Cetradonia linearis [Gymnoderma lineare] (Fed E, State E | S1 G2)

Habitat. High humidity environments on moist cliffs at high elevations or moist boulders in deep river gorges.

Range. Endemic to the southern Appalachians.

Notes: A squamulose lichen with an unknown photobiont that is suspected to be a species of Trebouxia, a green alga (Brodo et al. 2001).

Identification.“Grows in dense colonies of narrow (.04 inch) straps that are blue-grey on the upper surface and generally shiny-white on the lower surface: near the base they grade to black (the similar species of squamulose Cladonia are never blackened toward the base). Fruiting bodies are borne at the tips of the straps & are black (similar Cladonia species have brown or red fruiting bodies).”(USFWS)

Additional resources. NHP | USFWS | Recovery plan

Helonias bullata
Cetradonia linearis habitat
Habitat of Cetradonia linearis(Photo: Krings)
Cetradonia linearis habitat
Habitat of Cetradonia linearis(Photo: Krings)
Cetradonia linearis
Cetradonia linearis(Photo: Krings)
Cetradonia linearis
Cetradonia linearis(Photo: Krings)
Cetradonia linearis
Cetradonia linearis(Photo: Krings)
Cetradonia linearis
Cetradonia linearis(Photo: Krings)
Cetradonia linearis
Cetradonia linearis(Photo: Krings)

Cetradonia linearis*
(rare [Fed E, S1 G2]; humid environments, moist cliffs at high elevations, moist boulders in river gorges; Mt; year round)