Description: This is one of the smallest of the Leptogium species often inhabiting the trunk and root plates of old ash trees. The entire thallus is barely one centimetre across, usually starting off as a grey-brown radiating rosette of narrow lobes, these later producing tiny, spiky extensions like small isidia. Sometimes thalli merge to form spreading colonies. Discs very rare. It will also grow on mosses on lime-rich soils and on acid rock affected by blown lime dust. Throughout Ireland.

Key Identification Features:

• Tiny one centimetre thalli, of narrow, spreading branches with numerous spiky extensions
• On old, sometimes senile ash trees and former parklands, estate grounds, golf courses, etc.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Scytinium teretiusculum at iNaturalist World Species Observations database.