As this species is quite variable, several subspecies are sometimes recognized:

subsp. geographicum, syn. R. tinei (Tornab.) Runemark subsp. vulgare Runemark

On exposed, siliceous rocks, either on natural outcrops or on artificial substrates.

Belgium: Brab.: RRR (†<1900), Mosan: RR, Ard.: AC.

Luxembourg: Ard.: AC.

France: - .

subsp. diabasicum (Räsänen) Poelt & Vězda

On exposed, siliceous, natural outcrops.

Belgium: Ard.: R.

Luxembourg: Ard.: RRR.

France: - .

subsp. lindsayanum (Räsänen) comb. ined. [provisionally placed here, art. 34.1b], syn. R. lindsayanum Räsänen subsp. lindsayanum

On exposed siliceous rocks, either on natural outcrops or on artificial substrates.

Belgium: Brab.: RRR (†<1900), Mosan: RRR, Ard.: AR.

Luxembourg: Ard.: AR.

France: - .

Lit.: L8: 74, NL77: 23, NL84: 17, NL92: 173, Ertz: 20, Runemark (1956: 122, 133).