• Arthonia astroidestera Nyl.
Arthonia astroidestera
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(Map updated: 11 August 2009)

Rare in Ireland, this small epiphytic lichen of smooth-barked trees in old, oceanic woodlands, is usually noticed on account of its tiny frosted discs, so it is easily overlooked, especially if there appears to be little else but bare bark present. Holly is an especially favoured host. The creamy thallus, usually surrounded by a brown line, has discs irregularly branched or star-shaped (to 1.2mm diam.). Under a UV lamp the fruits glow a beautiful bright orange-yellow. Western Ireland.

Key characteristics

  • Thallus creamy, with a brown margin; on smooth bark in humid parts of old woodlands including near water, pits and slopes
  • Discs frosted, star-shaped; UV+ orange-yellow.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Arthonia astroidestera Nyl.. [In] LichenIreland. Accessed on 2019-08-25.