There are still pockets of Wingstem (Verbesina alternifolia) in bloom along the Delaware and Raritan Canal in central New Jersey. This species has been flowering in nearby locations since August.
Like so many other plants that bloom in late summer and fall, Wingstem is a member of the prolific Aster (Asteraceae) family, which consists of more than 23,600 species.
Aster family members have a floral display that is a composite of multiple flowers, called a flower head, inflorescence, or capitulum. What our brain wants to interpret as a single flower is really a group of many flowers, all attached to the same platform, or receptacle.
There are two types of flowers that may be present in the flower head of an aster family member, ray flowers and disk flowers. Each ‘petal’ we see is an individual ray flower that consists of a single petal. The other type of flower is a disk flower, whose petals have fused to form a narrow tube. Many Aster family members have a classic look with both ray and disk flowers, while some have evolved to produce just ray flowers, and others just disk flowers.
For many species that produce both ray and disk flowers, the ray flowers are sterile; they don’t have functioning reproductive parts. Their role is just to look pretty, to be part of an appealing advertisement that attracts pollinators to the disk flowers in the center of the flower head. It’s the disk flowers that produce pollen and nectar, and where the business of reproduction is carried out.
Wingstem is a species that has sterile ray flowers and fertile disk flowers, all attached to a rounded receptacle. The disk flowers are large and distinct; it’s easy to see each individual flower, especially when insects are foraging for food.
Like its relatives, Wingstem is a great source of food for late season pollinators. The ray flowers open first as a signal to pollinators that the flower head is open for business. The disk flowers bloom a few at a time, starting with those closest to the ray flowers, then over many days gradually working towards the center of the head. In each disk flower, the male reproductive parts (stamens) mature first, opening their anthers to make pollen available. Later the female reproductive parts (pistils) replace the stamens, the stigmas at the tips of the pistils becoming receptive to pollen. At any time while in bloom there may be some flowers in a head that are in the male phase, others in the female phase.
It’s easy to see how the pollen-covered Bumble Bee in the photo below would be an effective pollination partner for Wingstem.
Not all pollen is destined to be used for pollination, however, since it’s an importance source of food for bees and flies. Bees and flies drink nectar, but they also eat pollen. Female bees also collect pollen to bring back to their nests to feed their larvae. The female below already has a good quantity of food to bring to her offspring, packed onto the bristly hairs on her hind legs.
Sweat Bees and Small Carpenter Bees also visit Wingstem flowers for the nectar and pollen banquet they provide.
This Toxomerous geminatus, a Flower Fly, may not have a tongue long enough to reach the nectar, but it can still consume pollen from these abundant flowers.
Wingstem nectar is a welcome offering for butterflies.
Even this thread-waisted wasp is doing her best to get into the flowers to drink nectar.
If these insects assist in transporting pollen to help achieve successful pollination, the disk flowers will produce dry, winged fruits (achenes) that will take the place of the flowers on the globe-shaped receptacle. The fruits may drop in place, be scattered by wind, or dispersed with the assistance of a passing animal hooked by the pointy bristles on each achene.
Deer and other mammals avoid eating Wingstem because of its bitter taste. But there are some insects that happily get nourishment from this species. The caterpillars of Silvery Checkerspot butterflies and some moths eat Wingstem leaves.
The aphids in the photo below are feeding on Wingstem sap, while the ants are drinking the aphids’ honeydew (excrement). The ants will protect the aphids in exchange for this treat.
Wingstem is an herbaceous perennial that often grows to a height of 5-6 feet (1.5-2 meters), but can reach eight feet (2.5 meters) tall. It can tolerate full sun to part shade, average to moist soil. This plant’s name describes its appearance, providing clues to its identification. ‘Wingstem’ refers to the leafy wing-like appendages along the sides of the main stem of the plant. ‘Verbesina’ means that its foliage is similar to that of verbena, and ‘alternifolia’ tells us that the leaves are alternate, not opposite each other where they attach to the stem.
Wingstem is native in the United States in Massachusetts, Rhode Island, and from New York west to Nebraska, south as far as northeastern Texas and the Florida panhandle. In Canada, it can be found in Ontario province. Wingstem is less common in the northern and southernmost parts of its range.
Look for Wingstem and its visitors in late summer and fall.
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Eaton, Eric R.; Kauffman, Ken. Kaufman Field Guide to Insects of North America. 2007.
Rhoads, Ann Fowler; Block, Timothy A. The Plants of Pennsylvania. 2007
Stearn, William T. Stearn’s Dictionary of Plant Names. 1996
Wagner, David L.; Caterpillars of Eastern North America, 2005.