Bacidina ferax was first described by lichenologist Stefan Ekman as a new species in 2023, with the type specimen collected from Uppland, Sweden on Salix cinerea.

The species epithet ferax is a Latin adjective meaning "fruitful", alluding to the abundance of apothecia produced by this lichen.

[1] Bacidina ferax forms a crustose thallus composed of rounded to effigurate (formless) areoles that fuse together, creating a continuous crust.

[1] Bacidina ferax is primarily found in central and northern Sweden, including the provinces of Värmland, Uppland, Dalarna, Gästrikland, and Jämtland.

It grows on the bark of various phorophytes, such as Salix cinerea, Alnus glutinosa, Populus tremula, and Quercus robur, at or above the highest water level.