This annual weed is a diploid (2n = 16), widespread in northern and western North America, but perhaps native only in Eurasia. It is rare or absent in southeastern states, except in or near the Blue Ridge and Piedmont (PL, W). In Ky. it is known from a coll. originally identified as E. inconspicuum (S. Watson) MacMill.: JEFF (DHL), C.R. Gunn #J20, 11 Apr 1954; one colony between River Rd. and railroad, open low grass in parking area no. 2. Also, during 2014 a few plants appeared in the garden of JC (FAYE).