This distinctive southwestern annual (2n = 12) is extremely rare east of the Mississippi Rv. (FNA 19, W). It was discovered by R. Seymour on clifftops of Indian Hill, near Brownsville in EDMO. Although confirmed by JC, there has been lingering doubt about distinction from virginica, which also occurs at this site (A. Dattilo, pers. comm.). D. Boone (pers. comm.) found 1000s of occidentalis plants here in 2011. The site is also notable for a small population of Trifolium reflexum, and a long history of pre-DeSotan human occupation.