This species establishes a symbiosis with nitrogen-fixing cyanobacteria of the genus Nostoc, which are housed in special cavities, called auricles, occurring on the ventral (underside) surface of the thallus.

[4][5][6] Blasia is distinguished from Cavicularia by the presence of a collar around the base of the sporophyte capsule, and a scattered arrangement of sperm-producing antheridia.

Rhizoids and gemmae of Blasia may be parasitized by the mushroom Blasiphalia.

The genus name of Blasia is in honour of Blasius Biagi (ca.

1670 - 1735), an Italian clergyman from village of Vallombrosa.