This is a northern and western species that appears native along the Mississippi Rv., but more eastern records may be adventive (FNA 4). The genus has previously been considered native only in Eurasia (e.g. Cr), and the name C. hyssopifolium L. was misapplied to much American material.The only Ky. records are colls. of R. Athey (MEM?), E.T. Browne (MEM) and D. Pittillo (EKY), from sandy banks of the Mississippi Rv. in FULT. These plants have been erroneously reported as var. rydbergii Mosyakin or C. villosum Rydb. (BA).