I’ll go out on a bit of limb here and identify this as Cucumberleaf Sunflower (Helianthus cucumerifolius). It is no mean feat to pinpoint the species since sunflowers are in Asteraceae*, the largest botanical family with a mere 32,000+ members. I feel moderately confident in my choice since it is commonly found here, tolerates sandy soil, and blooms this time of year. Beautiful, no matter the name.

*Asteraceae- from ancient Greek meaning star, referring to the rays of the flowers.