• Tremolecia atrata (Ach.) Hertel.
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Tremolecia atrata
© Mike Simms
Tremolecia atrata
© Mike Simms
Tremolecia atrata
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This unmistakable crustose lichen has a characteristically bright, red-brown thallus sometimes dulling in shaded situations with flat, black discs with no surface ornamentation. It occurs mostly on hard, siliceous rocks and is especially abundant where the geology includes formations with a high iron or metal-bearing content. It is scattered in suitable habitats throughout Ireland.

Key characteristics

  • The rich, reddish-brown colour helps to indicate this species. Rhizocarpon oederi is similar, but the discs have a spiral, or creased (gyrose) surface ornamentation (best seen with a lens)
  • Usually associated with acid rocks that are rich in quartz and/or metal-bearing minerals.

Original text submitted by Simon Davey

 Simms, M. J., (2016). Tremolecia atrata (Ach.) Hertel.. [In] LichenIreland. Accessed on 2018-07-16.