Autumn Sneezeweed

Media
Photo of autumn sneezeweed flowerheads, closeup.
Scientific Name
Helenium autumnale
Family
Asteraceae (daisies, sunflowers)
Description

Autumn sneezeweed is a late-blooming perennial with branching, winged stems. Flowerheads are many, all yellow, with 10–18 ray florets fan-shaped, notched, reflexed downward. The large disk is dome-shaped. Blooms August–November. Leaves are basal or mostly on the lower parts of the stem, with only smaller leaves on the upper stems; alternate, narrowly lance-shaped, with or without a few teeth; the leaf tissue extending down the stem as wings.

Similar species: Four heleniums grow in Missouri. Bitterweed and purple-headed sneezeweed have their own entries in this guide. The fourth, Virginia sneezeweed (H. virginicum) is the most like autumn sneezeweed. A state endangered and federally threatened species, it only occurs in about 9 of our southern Ozark counties, primarily in boggy, sinkhole pond habitats. Oddly, the only other populations in the world are in the state of Virginia, and nowhere else. It is found in moister soils than autumn sneezeweed, and its leaves are well-developed along the leaf stem; basal and lower leaves are absent at flowering; it blooms July–September.

Common Name Synonyms
Common Sneezeweed
Size
Height: to 6 feet.
Where To Find
image of Autumn Sneezeweed Common Sneezeweed Distribution Map
Scattered nearly statewide except Southeast Lowlands and the northwestern section of the state.
Occurs on banks of streams, rivers, and spring branches, margins of ponds, lakes, and sinkhole ponds, sloughs, fens, and seeps, marshes, bottomland prairies, moist depressions of upland prairies, and bottomland forests; also pastures, ditches, railroads, roadsides, and moist, open, disturbed areas.
Collections made by Julian Steyermark in Howell County in 1960 of unusual but similar plants were long thought to be oddball hybrids of autumn sneezeweed and purple-headed sneezeweed. But in 2000 DNA testing proved they were not descendants of those species and showed instead they were Virginia sneezeweed, until then known only as an endangered plant growing along sinkhole ponds in the Shenandoah Valley. How did this plant come to have such widely separated populations? Apparently they are relict ranges of what had long ago been a single, broad range, before ice-age glaciers split it up, and the populations shrank to their current tiny ranges.
Sneezeweeds were used historically by Native Americans and pioneers as snuff. Inhaling the dried, powdered disk florets caused violent, prolonged sneezing, and people did this as a way of alleviating colds, stuffy noses, headache, and other maladies.
Numerous bees, wasps, flies, butterflies, and beetles visit the flowers for nectar and pollen. Aphids suck the sap, and moth caterpillars bore in the stems. Sneezeweeds contain toxic, bitter substances, and grazing mammals, including cattle, avoid eating them.
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About Wildflowers, Grasses and Other Nonwoody Plants in Missouri
A very simple way of thinking about the green world is to divide the vascular plants into two groups: woody and nonwoody (or herbaceous). But this is an artificial division; many plant families include some species that are woody and some that are not. The diversity of nonwoody vascular plants is staggering! Think of all the ferns, grasses, sedges, lilies, peas, sunflowers, nightshades, milkweeds, mustards, mints, and mallows — weeds and wildflowers — and many more!