Hieracium murorum L.
Wall hawkweed is a European native that has found its way to North America prior to 1900. The rather curious name comes from its affinity for rocky slopes and walls.
Identification: Plants are 10-24" (25-60 cm) in height, with hairy stems. Only 3-6 leaves appear at the base of the plant, sometimes with two or three more on the stems. Leaves are elliptic, 1¾-4" (5-11 cm) × ⅞-1¾" (2.5-4.5 cm), sometimes mottled with purple. Leaves are unusual in shape, wide at the base, with large, forward-pointing teeth that fall somewhere between the designation of “tooth” vs. “lobe.” Flower heads appear as 5-8 corymbs. Flowers are yellow, with 30-50 or more florets, about ½" (1.3 cm) in size. They flower in June.
This hawkweed comparison table is an aid to identifying hawkweeds and similar-appearing species.
Hieracium murorum at the University of Wisconsin's Robert W. Freckmann Herbarium
Hieracium murorum at Skye Flora
Hieracium murorum on eFloras
Hains, Arthur; Farnsworth, Elizabeth & Morrison, Gordon (illus.), Flora Novae Angliae: a Manual for the Identification of Native and Naturalizaed Higher Vascular Plants of New England, Yale University Press, 2011, p. 412
Hieracium murorum description by Thomas H. Kent, last updated 5 Oct 2016.