• Arthonia elegans auct.brit.
Arthonia elegans
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This small, mosaic-forming epiphyte consists of straight, flattened discs sprinkled about the bark in patches. The yellowy, orange-flushed thallus is immersed in the bark surrounded by an orange-brown margin. The pointed or star-shaped, purple-brown discs (0.3-1.6mm long) are sometimes powdered red along the edges. It grows mostly on smooth bark, for example, hazel and young oak. North and west Ireland. The discs turn purple with a dab of K (Potassium hydroxide).

Key characteristics

  • The straight or jagged, star-shaped discs, K + purple with red powdery edges (pruina) and habitat of smooth bark in old woodlands should distinguish it
  • Arthonia cinnabarina is similar but has larger, more rounded discs: pink powdery or brown.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Arthonia elegans auct.brit.. [In] LichenIreland. Accessed on 2018-08-18.