The fungal body (thallus) can appear in several forms – it may be barely visible, cracked, warty, or divided into small polygonal areas called areoles.

They have a distinctive microscopic structure, including specialised cells called paraphyses that have abruptly swollen tips capped with dark brown pigmentation.

The spore-producing cells (asci) typically contain eight spores, though occasionally up to 16, and show a characteristic blue reaction when treated with iodine-based stains.

[4] The genus can be distinguished from similar lichens by its combination of asci that turn blue with iodine, paraphyses with dark-capped swollen tips, two-celled spores without a gelatinous coating, and spore-producing cells arranged in chains.

While the similar genus Halecania shares many of these features, it differs in having thick-walled spores with a distinct gelatinous coating and is not closely related based on genetic analysis.