Syn.: C. lactea auct. p.p., non (A. Massal.) Zahlbr.

On hard calcareous, tufa and sandstone rocks, also common in artificial habitats, in dry and sunny places, often parasitic, at least when young, on black crustose lichens (Verrucaria nigrescens, cyanobacterial crusts), usually in nitrophilous conditions.

Belgium: Mar.: RR, Fl.: RRR, Camp.: RRR, Mosan: R, Lorr.: RR.

Luxembourg: Lorr.: AR.

France: Mar.: RRR, Lorr.: RR.

Lit.: Boul.: 67, Navarro-Rosinés & Hladun (1996: 148).