Description: This is one of the ‘bark-pimple’ tribe where collection from small twigs of ash, aspen, alder and hawthorn for microscopic identification is essential. It has the appearance of Arthopyrenia punctiformis (described elsewhere) but differs in the spores (11–17µm long) which are up to four-septate and often becoming submuriform.

Key Identification Features:

• On twigs, perithecia up to 0.2mm diam., spores becoming submuriform
• Easily mistaken for Arthopyrenia punctiformis.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Cyrtidula hippocastani at iNaturalist World Species Observations database.