Leavenworth's Tickseed - Coreopsis leavenworthii

There are few wildflowers that say "wildflower" better than Leavenworth's tickseed (Coreopsis leavenworthii).  It is found statewide in a variety of habitats, is nearly endemic (found in a few locations in Georgia), and is essentially the wildflower adopted as the official state wildflower (though the state legislature selected the overall genus and the license tag depicts the non-native, C. basalis, which is a bit showier).  Often, this species is simply referred to as "coreopsis" when a discussion centers on it and it is widely propagated in the native plant industry.
Leavenworth's tickseed is most frequently encountered in moist sites, but is very adaptable and can be found in a variety of upland areas as well.  Though described as a perennial, I find it to behave more as an annual. If plants survive past their first year, they are extremely short-lived perennials.  They proliferate profusely, however, by producing large numbers of seed. In a natural or home landscape setting, this often results in the plant forming extensive colonies. 
Leavenworth's tickseed is a thin plant with narrow leaves and a narrow crown.  In my garden, it emerges in early spring and quickly grows to a mature height of 18-24 inches.  Many small flowers are produced at the ends of each branch from summer into fall, though it may bloom through the year in extreme south Florida.  Each flower is about one inch across; the bright yellow ray petals surround a darker disc. Like all members of the aster family, these blooms are of great interest to pollinating insects.
Because of its adaptability, its ability to persist and thrive in most landscape settings, and its cheery blooms that occur for months before declining, Leavenworth's tickseed is an extremely popular wildflower for the home landscape.  Ours has persisted for more than a decade in our landscape without any supplemental care. The only thing that keeps it in check are the cottontail rabbits that love to eat it and the occasional weeding I do to keep it in bounds. This is a widely propagated species and should be easy to locate from commercial sources.  Do not deadhead spent blooms for at least a month after flowering has finished if you want this plant to reseed and persist, and because the seeds are small, do not mulch it too heavily.

Florida Tickseed - Coreopsis floridana

 

Florida tickseed (Coreopsis floridana) is a perennial member of this well-known genus and endemic to Florida.  It occurs throughout most of the state, except the extreme northern Panhandle counties, in wet open habitats such as the upper edges of marshes, savannas and prairies.  The photos above were taken at Kissimmee Prairie Preserve State Park in mid-October in moist soils.
Florida tickseed is superficially similar to many of the other yellow-flowered species in Florida, but it is much more robust than the annual C. leavenworthii and C. gladiata, and it is a fall bloomer.  Florida coreopsis eventually stands about three feet tall. The bright yellow ray petals, surrounding the dark disc flowers form a bloom that is two inches across. The leaves are narrowly elliptical in shape.
Florida coreopsis is occasionally offered for sale by nurseries affiliated with FANN - the Florida Association of Native Nurseries, but it is a plant that requires wet to moist soils to survive and is not a good candidate for typical landscape settings.  Its best use is at the upper edge of a wetland feature where it would get consistent moisture.  In such settings, its perennial nature and its showy flowers make it a beautiful wildflower addition.

Coastalplain Rayless Goldenrod - Bigelowia nudata subsp. australis

Coastalplain rayless goldenrod (Bigelowia nudata subsp. australis) is the Florida-specific form of a wildflower distributed along the Gulf Coast from Texas to North Carolina.  The australis subspecies is found throughout the Florida peninsula, except in the very extreme southern tip. These are in the Aster family, but are not closely related to the true goldenrods - genus Solidago.
This perennial is a species of wet open habitats. It dies to the ground in winter and emerges each spring.  Strap-like basal leaves, about one inch long, are soon formed, but these are easily overlooked amidst the grasses and other forbs with which it grows. It makes its full appearance in late spring to fall when the thin 1-3 foot tall flower stalks produce their numerous canary yellow blooms.  As its common name implies, the flowers do not have ray petals, like many other asters.  The tubular flowers are packed into flattened heads that look a bit like candelabras.  Plants are often found in colonies, and these are striking during their several-week blooming season.  They also attract the attention of pollinators.
Florida is home to two species of rayless goldenrod. I have posted previously on B. nutallii. The latter species is quite rare in Florida, found only in excessively well-drained sandy habitats, and has leaves that are even narrower than those shown above.
Coastalplain rayless goldenrod would make a beautiful addition to a wet prairie garden, but its need for moist to wet soils precludes its use in most home landscape settings.  it is not currently offered for sale by any nursery associated with FANN - the Florida Association of Native Nurseries.

Coastal Plain Milkwort - Polygala setacea

Coastal plain milkwort (Polygala setacea) is a diminutive species that is fairly easy to overlook during its summer-fall blooming season.  Native to most of Florida, and north up the Southeast Coastal Plain to North Carolina, it is resident to moist pine flatwoods, open savannas and prairies.  The flowers pictured here were found at Kissimmee Prairie Preserve State Park, just north of Lake Okeechobee in mid-October. 
Like most other members of this genus, it is an annual. Its slender stems reach a mature height of 6-12 inches, and rise above small basal leaves.  The narrow raceme of white flowers is no more than 1/2 inch long. The flower structure is very similar to that of other milkworts; the bright yellow anthers are obvious as they extrude from the open blooms.
This is a plant that is common in the right habitat, but often goes unnoticed.  The blooming season is several months earlier in more northern regions of its range. Look for it as you hike the type of moist open areas where so many other milkworts also reside.