Hormiscium ericae

A remarkable ascomycete forming black crusts or cushion-like pustules parasitizing the twigs of tree heath (Erica arborea), commonly known in Spanish as 'carbón de brezo' (heath charcoal).

Microscopic examination reveals the peculiar morphology of its conidia: globose cells arranged in fragile, easily disarticulating chains of variable length.

Likely more common than the scarce mycological literature suggests, since its charcoal-like appearance causes it to be frequently passed over.

We recorded this species in March in Oña (Burgos), where it was colonizing nearly every individual of Erica arborea across substantial patches of heathland.