Lichens : Lecanorales : ParmeliaceaeLichens

Usnea fragilescens (Vain.) Clerc

Description: This beard lichen is much like other Usnea species in its yellow-green colour but is unlike most in the texture of its thallus which is soft and pliable. It is a fairly large and robust species next to its relatives with a distinctive orange patch just above its blackened base towards which it narrows quite acutely. It is local in humid woodlands, willow swamp etc., throughout Ireland though commoner in the west.

Key Identification Features:

  • Its flexible nature, acutely narrowing black holdfast with orange streak above, and large size of combed appearance should help identify it
  • The constriction in the thallus towards the base separates it from Usnea subfloridana as does the Pd (a lichen test reagent) + red reaction, Usnea subfloridana being Pd-.

Original text submitted by Simon Davey

Distribution Map from NBN: Usnea fragilescens at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Usnea fragilescens at iNaturalist World Species Observations database.

 Giavarini, Vince J., Simms, Michael J., & Davey, Simon, 2026. Usnea fragilescens. (Vain.) Clerc. [In] Lichen Ireland.
https://www.habitas.org.uk/lichenireland/species.php?item=39805. Accessed on 2026-11-12.