Yellowtop (Flaveria linearis) flowers are a sign of Fall, though not a sure sign. Tara McTaggart texted that her yellowtop bloomed in the Spring.
Pollinating insects, including butterflies, love to nectar on this wonderful wildflower, pictured above along the east side of Highway A1A at Sebastian Inlet State Park. Though many books characterize yellowtop as a plant of moist places, it is quite adaptable and resilient.
A short-lived perennial, this plant re-seeds prolifically and is an excellent choice for a butterfly or pollinator garden.