This monocarpic perennial weed (often more than biennial) comes from western Europe, has invaded east-central states during recent decades, and is now centered here slightly to the north of fullonum. It was first reported in Ky. during the 1970s (M), and it is spreading south, especially along major highways; see also Y. The species is much more widespread in Ky. than herbarium colls. indicate. D. laciniatus differs from fullonum in its distinctive pinnately laciniate leaves (versus entire to irregularly lobed), larger calyces (1.2-1.6 mm versus 0.9-1.2 mm), and strictly white flowers (versus usually with pink-purple corolla lobes and stamens). It tends to be more robust (W), up to 2-3 m tall (versus 1-2.5 m), and has more strongly developed perfoliate cups (Y). Hybrids with fullonum have been reported elsewhere (Cr), but not observed in Ky.; 2n = 16 and 18 in both species; see also note on sativus under fullonum.