||Helianthus petiolaris subsp. petiolaris
||Helianthus petiolaris subsp. petiolaris is one of two subspecies of Helianthus petiolaris, the prairie sunflower, an annual, branched sunflower species. The native range of H. petiolaris subsp. petiolaris spans most of North America, where it is generally found of sandier soils than H. annuus. Together with other wild sunflower species, it is a long-standing model system for speciation, adaptation and ecotype formation studies, and, more recently, genomic studies. Wild sunflower species, including Helianthus petiolaris, have also contributed numerous useful alleles to the cultivated sunflower gene pool.
Helianthus petiolaris subsp. petiolaris is diploid and has a relatively large (3.3 Gbp), extremely repetitive genome, organized in 17 chromosomes. Numerous large chromosomal rearrangements and structural variants distinguish its genome from that of other wild sunflowers.