Description: B. homalotropa can be found growing on smooth bark in the sheltered, oceanic woodlands of the west of Ireland where it is strongly associated with Thelotrema petractoides (described elsewhere) and many of the ‘scripture’ and ‘freckle’ lichens, for example, Graphis, Opegrapha, Phaeographis and Arthonia. The thin, grey thallus produces black, circular discs (0.2-0.6mm diam.) with a distinctive ragged edge quite unlike any other Irish species, so is not easily confused. It has needle-like, multiseptate spores with 50 or more divisions.

Key Identification Features:

• A smooth-bark species of sheltered, oceanic woodlands often growing with Thelotrema petractoides on hazel, holly or rowan
• Discs are round with a ragged margin; spores multiseptate, needle-like.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Bactrospora homalotropa at iNaturalist World Species Observations database.