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.

White-flowered Pricklypoppy - Argemone albiflora

Two species of pricklypoppies are native to Florida. The yellow-flowered one, Mexican pricklypoppy (Argemone mexicana) is common throughout much of peninsular Florida. The white-flowered species (A. albiflora), described in this post is found in the same locations. It is not uncommon to find both along roadsides in full sun and sandy soils.  These are members of the true poppy family.
White-flowered pricklypoppy is an annual with thistle-like foliage. The clasping, very spiny leaves are deeply lobed and the leaves are alternating along the stem. Multiple flower stalks are produced and reach a maure height of about 3-4 feet. The flowers are produced for several months from late spring through summer.  They are quite showy, with broad, frilly petals and bright yellow stamens (the male parts of the flower) in the center.  The pollinated flowers form spiny seed capsules that open at the top. The poppy-type seeds are then released over time as the seed capsules are shaken by wind and rain.
Although the flowers are quite attractive, the very spiny nature of this wildflower limits its attractiveness in a landscape setting. I am not aware that either species of pricklypoppy has ever been offered for sale commercially in Florida. It is extremely adaptable to open sunny locations and would be easy to grow. If you are interested, be careful to limit its spread to only those areas where its prickly nature won't be a problem.

Florida Tasselflower - Emilia fosbergii

Florida tasselflower (Emilia fosbergii) is a common non-native lawn weed, but an attractive one that is found in nearly everyone's landscape within peninsular Florida. It is not likely to be found in extreme north Florida or the Panhandle.  This is a widely distributed plant worldwide, and is reported from much of the West Indies, Mexico south to parts of Brazil, many western Pacific islands, tropical Africa, and parts of Indonesia.
Florida tasselflower is an annual member of the aster family. It comes up each year from the copious seed shed from the year before. A cluster of basal leaves forms early. They are diamond  shaped with a toothed margin and a "wing" along the leaf stem (i.e. the petiole).  A central floral stem is then produced that can reach 2-3 feet tall. The leaves along the stem do not have petioles .  Flower buds occur at the top of each stem. They open from late spring to fall on open heads. The petals are crimson to deep pink in color.  A closely related non-native species, lilac tasselflower (E. sonchifolia) has lilac-colored flowers - not crimson or pink.
Florida tasselflower produces a great many flowers and, when ripe, they produce a great many dandelion-type seeds. The fluffy appendages, attached to each seed, are designed to catch the wind and waft each seed far away from the parent plant.  If you allow your plants to go to seed, you will get a great many more each season. Florida tasselflower is extremely adaptable. It does very well in open sunny, disturbed locations as well as sites that are mostly shady. As a member of the aster family, its flowers draw pollinators. 
I choose to leave a few of these "weeds" alone each year in the corners of my landscape for the bees and butterflies, but I weed them aggressively in the other parts of my landscape. If you leave it completely alone, it will take over your landscape and likely become a nuisance.

Goldencrest - Lophiola aurea

Goldencrest (Lophiola aurea) is an erect perennial herb native to the central and western portions of the Florida Panhandle. Originally included in the same genus as redroot (Lachnanthes caroliana) there are superficial resemblances between the two, but also significant differences. For one, goldencrest has whitish to brownish roots - not red, and there are also differences in their chemical and pollen structure. Goldencrest, therefore, has been put in its own genus and this is the only species worldwide. It is found throughout the Deep South with disjunct populations being reported from New Jersey and Prince Edward Island. Goldencrest is a species of wet savannas, bogs and ditches where it gets full sun and nearly constant wet soil.

It dies to the ground each winter, and reaches a mature height of 1-3 feet in late spring.  The leaves are small, linear, and less than 1/4 inch wide. Flower heads are produced at the top of the stalk. They are open cymes with the stems and the flower heads covered by white wooly hairs.  The individual flowers are tiny with a yellow crest emerging from the top of the bud. Each of these flower buds ripens to a dry capsule in late summer.

Goldencrest has never been offered for sale commercially in Florida, to the best of my knowledge.  It is a common plant of the open savannas of Apalachicola National Forest (where these photos were taken), in the same types of habitats where pitcher plants, sundews, and grass pink orchids occur. Look for it in late spring.