Hieracium murorum, the wall hawkweed, is a species of flowering plant in the family Asteraceae. It is native to Europe and naturalized in some of the colder regions of North America.[2][3][4][5]
References
^illustration from USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 3: 329