• Celothelium ischnobelum (Nyl.) M.B.Aguirre
Celothelium ischnobelum
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(Map updated: 11 August 2009)

This crustose, bark lichen grows most prolifically on hazel, so look for it there. The thallus is pale greenish or a silvery, creamy-yellow when dry, but the giveaway feature is when it occurs in the pycnidial form. Through a lens these tiny spots are black, triangular and pip-shaped, sometimes even barbed like a thorn. Over one hundred would fit comfortably on the head of a nail. On hazel, in humid sheltered woodland, it occurs within mosaics of other species. Northern and western Ireland.

Key characteristics

  • Hazel specialist bark lichen, small (thallus 1-2cm across), pale, silvery-brown, with numerous dots, many merging
  • Dots (pycnidia) black, triangular, barbed, pinprick sized; often growing with Graphis and associated smooth bark lichens.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Celothelium ischnobelum (Nyl.) M.B.Aguirre. [In] LichenIreland. Accessed on 2019-08-19.