Syn.: T. absconditum (Hepp) Rabenh., T. amylaceum auct., non A. Massal., T. immersum (Leight.) Mudd, T. leightonii M. Choisy

On natural, calcareous outcrops, in exposed conditions.

Belgium: Mosan: AR, Ard.: RR, Lorr.: RRR.

Luxembourg: - .

France: - .

Lit.: Ertz: 37-38, Mü3: 48, Mü5: 18, NL84: 17, NL87: 23, NL97: 56, Zschacke (1933: 332, sub T. absconditum; 341, sub T. amylaceum).