The African species B. decurtata is an obligately saxicolous lichen, and while similar, it has a dark underside and produces salazinic acid in its medulla.

[2] Bulbothrix cinerea possesses a dark gray thallus and is saxicolous, measuring between 3 and 7 centimetres (1.2 and 2.8 in) wide, being tightly adnate.

The species' ramification is irregularly dichotomous, with rounded apices, a crenate margin with a black line.

Its medulla is white, with a chestnut-dark brown coloured underside, being rugose, veined and papillate.

[2] This saxicolous species finds itself tightly attached to its substrate and is frequently found on exposed quartzite rocks.