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 12 Oct 2018.