Lichens : Verrucariales : VerrucariaceaeLichens

Agonimia gelatinosa (Ach.) M.Brand & Diederich

Description: Formerly listed under the name Polyblastia gelatinosa, this lichen resembles tiny black spherical specks superficial on calcareous soils. The thallus as such is barely visible, but through a lens it is possible to make out tiny brown rounded granules (goniocysts) scattered on the surface. The spherical specks are the discs (perithecia) which are smooth. One should also notice an absence of even smaller black globules that are characteristic of the related species A. globulifera. The spores have 16-30 cells visible through the optical microscope. It should be searched for on limestone and calcareous soils. In Ireland, records are scattered through the Midlands, western and northern Ireland.

Key Identification Features:

  • Thallus brown, of tiny goniocysts; perithecia, smooth, black, almost superficial on the limestone soil
  • Black globules absent; spores to 55ųm long with 16-30 cells visible.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Agonimia gelatinosa at iNaturalist World Species Observations database.

 Giavarini, Vince J., Simms, Michael J., & Davey, Simon, 2026. Agonimia gelatinosa. (Ach.) M.Brand & Diederich. [In] Lichen Ireland.
https://www.habitas.org.uk/lichenireland/species.php?item=20624. Accessed on 2026-11-12.