We collected achenes (single seeded fruits) from seven Helianthus annuus and seven H. debilis individuals in Texas. Four of the H. debilis individuals were initially labeled as H. praecox, yet these clustered with H. debilis individuals genetically (see below). As molecular phylogenetic studies of Helianthus also place H. praecox within H. debilis , we follow an early taxonomy that subsumes H. praecox into H. debilis. In addition, we acquired twelve H. petiolaris accessions spanning the distribution range of the species, either from USDA collections or from previous sampling efforts