This is a widespread annual weed in pantropical to warm-temperate regions. Its native or alien status in the Ohio Valley remains uncertain. Under old synonyms, there are early Ky. records from Short (1833) and Rafinesque (1836a); and B noted a coll. of Short from "barrens of Ky." at Univ. of Cincinnati. S. occidentalis (L.) Link is another weedy annual that may be expected in Ky. It has a similar range but is relatively infrequent or rare to the north (PL).