Arabis collina Ten. (syn. A. muralis Bertol.) (S-Eur.) – A very rare and much decreasing (possibly extinct) escape from cultivation. Already known around 1850, especially in the area around Verviers and Ensival and very well-established at various locations (but apparently no longer collected/observed since 1947). Furthermore known from rather few places, all in Wallonia (Liège, Poilvache, Trimottet). Arabis collina always grows on old walls or calcareous rocks.
More recent records (viz. Silenrieux, 1968 and Sosoye, 1983) finally proved to be in error for native Arabis hirsuta.
Arabis collina is no longer cultivated as an ornamental in Belgium and future occurrences are therefore rather unlikely.
Gerstberger P. (1995) Arabis muralis Bertol. (Brassicaceae) eingebürgert bei Bad Berneck im Fichtelgebirge. Ber. Bayer. Bot. Ges. 65: 133-135.