Phlyctis argena

Growth type crustose
Chemical results: K+ yellow turning red, C-, KC+ red, P+ orange-red, UV-

Usually on well-lit deciduous trees, rare on conifers, occasional on shaded, +/- basic rocks and walls.

Pale grey-green or whitish thallus with paler prothallus. White to greenish soredia, sparse or abundant and +/- covering thallus centre. Apothecia are rare, the pruinose discs greyish-black with thin margins.
Host to Opegrapha zwackhii; spores 3-4(-5) septate, 18-24 x 6-8 Ám

Similar: Phlyctis agelaea. Apothecia frequent, soredia absent.
Ochrolechia subviridis is K-, C+ orange > red

Phlyctis argena

Phlyctis argena

Phlyctis argena
On Oak. Holton Lee, Dorset. December 2012

All images used are copyright. Please contact me if you find errors.