Looking for Virginia sneezeweed? Check Missouri
In October 1957, when most Americans were gazing skyward for sightings of Sputnik, Julian Steyermark was captivated by something he found growing on the side of the road in rural Missouri.
A respected botanist who literally wrote the book on Missouri’s flora, Steyermark was the right person to stumble upon a mysterious plant. But he was stumped. It was “a most puzzling specimen of Helenium,” he recalled in an article published in 1960 in Rhodora, the journal of the New England Botanical Club.
Helenium, a genus of perennial plants in the sunflower family, commonly known as “sneezeweed,” is not rare in Missouri. But Steyermark’s specimen didn’t quite match either of the known native species, common sneezeweed and purple-headed sneezeweed. It possessed significant characteristics of both.
He theorized it was a hybrid of the two.
John Knox had another hypothesis. In October 1989, he drove 800 miles from Lexington, Virginia, to Pomona, Missouri — the site of Steyermark’s discovery — following directions the botanist left in the footnote to his entry for common sneezeweed in the Flora of Missouri. A clue to lost treasure.
“It said something about a hybrid population, a mile and half east of Pomona on Route N,” said Knox, a professor at Washington and Lee University. “And there it was, on the south side of the road, growing on the edge of a farm pond.”
He collected some seeds, and brought them back to Virginia to see if it was what he thought it was. Not a hybrid of two Heleniums, but an unexpected occurrence of another one: Helenium virginicum, or Virginia sneezeweed.
It was the second time he had gone looking for this plant beyond the boundaries of conventional wisdom. The first time was in Virginia itself, in the 1970s, at a time when the species was believed to be endemic to Augusta County in the Shenandoah Valley. Knox thought he had seen it other places too.
He confirmed it through a multi-year “common garden” experiment, which involves transplanting different plant species to the same controlled environment to compare their development. Knox documented subtle distinctions between common sneezeweed and specimens of what he believed to be Virginia sneezeweed found outside of Augusta County.
Then, he transplanted healthy adult plants from both species to each other’s habitats in the wild. As he figured, the suspected Virginia sneezeweed didn’t last long on the shady riverbanks where common sneezeweed felt right at home, and the common sneezeweed couldn’t handle the sunny, ephemeral wetlands where Virginia sneezeweed thrived despite irregular periods of flooding and drought.
After bringing home the seeds he collected from Steyermark’s site in 1989, Knox conducted another common garden study to demonstrate that the Missouri population was indeed Virginia sneezeweed. More than a decade later, in 2001, his experimental findings were confirmed through genetic testing. The identity of the Steyermark’s puzzling Helenium had become a question of national interest.
Just three years earlier in 1998, with only 25 confirmed populations in its namesake state, Virginia sneezeweed had been listed as threatened under the federal Endangered Species Act. Confirming that this plant was growing in Missouri could be a step toward recovery.
It turned out to be a giant leap toward recovery. Thanks to discoveries made in Missouri in the last two decades, the U.S. Fish and Wildlife Service is now recommending Virginia sneezeweed be removed from the list.
Bumper crop
In October 2001, after genetic testing had reaffirmed the identity of the puzzling Helenium, Rhonda Rimer from the Missouri Department of Conservation returned to the site of Steyermark’s discovery with a team of scientists: Paul McKenzie from the U.S. Fish and Wildlife Service, George Yatskievych from the Missouri Botanical Garden, and Kim McCue from the Center for Plant Conservation.
Together, they collected seeds for another experiment — a pilot propagation effort. McCue grew Virginia sneezeweed in a greenhouse, and then the team transplanted the seedlings to two sites on public land near the parent population.
Rimer, a natural history biologist who had been appointed Missouri’s recovery lead for Virginia sneezeweed in 2000, had low expectations.
She explained that rare plant reintroductions are often unsuccessful. “There’s so much that can go wrong.”
Surprisingly, everything went right. “Oh my gosh: it was like a bumper crop,” Rimer recalled. “We were out there counting flowers, measuring stems, thinking: how could this rare plant be so easy to grow, and not be growing somewhere else?”
Rimer organized a search party. She recruited Missouri botanist and author Bill Summers, and the two pored over topographical maps, beginning around Pomona. At first, they focused on sites that possessed a tell-tale geological feature: sinkhole ponds, where the plant is known to grow in Virginia. These rare wetlands only occur in areas underlain by limestone, where erosion from acidic groundwater causes subterranean caves to form. Occasionally, a cave collapses underground, leaving a depression on the surface. Some fill with water and become ponds.
But Rimer and Summers changed course when they started finding Virginia sneezeweed in roadside ditches and farm ponds that mimicked the conditions in natural sinkholes.
They expanded their search, and found dozens more locations, mostly on private land, thanks to landowners who welcomed their request to look for it. “Nobody told us ‘no,’ which is pretty amazing,” Rimer recalled.
Most were cattle producers who own large swaths of grazing land. “Once they realized they could just keep doing what they were doing, they were fine with it,” she said. “Cows don’t seem to eat Virginia sneezeweed, unless there is absolutely nothing else to eat.”
They discovered several other populations on right of ways, managed by the Missouri Department of Transportation, which adjusted its mowing and spraying regime to better accommodate Virginia sneezeweed while keeping invasive species at bay.
There are now more than 60 known populations in Missouri — more than in Virginia. Of those in Virginia, six are on land managed by the U.S. Forest Service, and two are on state-owned land within Natural Area Preserves, specifically dedicated to preserving the sinkhole habitats used by Virginia sneezeweed.
Rimer thinks Knox’s research suggests more populations will be discovered. In 1996, he and a student initiated a long-term seed viability study, which involved burying Virginia sneezeweed seeds in the sand contained inside small vials with porous lids, and checking them periodically to measure percent germination.
“For 11 years, there was no loss of viability in the seeds,” Knox said. They might have remained viable even longer. But something, or someone, dug the vials up, prematurely ending the experiment.
Still, the takeaway was clear: the seeds could remain viable underground for at least a decade, with no signs of life on the surface.
Hidden in plain sight
Based on a recently completed five-year review that reflects population, genetic and habitat data on Virginia sneezeweed collected since 1998, the U.S. Fish and Wildlife Service recommends removing the species from the list of those considered threatened or endangered under the Endangered Species Act.
The review suggests the species is not at risk of extinction in the near term. At the time of listing, the greatest threat to the species was habitat loss from projected future development. “That anticipated level of development didn’t pan out in the parts of Virginia where the species occurs, and of course, we found so many new populations in Missouri that have remained stable over the last two decades,” explained Kim Maison, the species lead for the Service.
The five-year review also affirms there are more discoveries to be made. In October 2018, botanist Justin Thomas discovered a population of Virginia sneezeweed in a nature preserve in central Indiana.
Although Knox and colleagues later confirmed the identity of this population through genetic analysis, its origin remains a mystery.
While the Missouri population of Virginia sneezeweed might seem out of place, so-called disjunctive populations that are isolated from the rest of a species’ range can be explained by geological factors. Advancing glaciers could have forced populations of Virginia sneezeweed in the intervening states to retreat, or a documented 3,000-year period of warming that began 9,0000 years ago may have dried out wetlands in those areas.
But the Indiana population is harder to explain. Since its discovery, state botanists have been looking for additional populations in southern Indiana, where there is likely to be more suitable habitat. To no avail.
And the site where the new population was discovered is a restored wetland, reseeded with wetland plants in the late 1990s. Could seeds of Virginia sneezeweed have been among those used in the restoration?
It seems likely, but Knox has been unable to track down the supplier of the seeds used for project. The company that undertook the restoration effort changed ownership a few years ago, and the new owners purged all previous records.
In late summer, Knox plans to get in his car and drive the 500 miles to Fishers, Indiana, to count plants, collect more samples for further genetic testing, and if he has time, look for more populations.
As he pointed out, the lack of evidence doesn’t necessarily mean they’re not there.
Consider Missouri. As part of his research, Knox and a student examined more than 1,000 herbarium specimens of common sneezeweed collected before 1990, looking for mistakes — specimens that were actually Virginia sneezeweed, but had been misidentified. They came up empty handed.
“Steyermark and others were good collectors,” Knox said. “How is it we examined so many specimens collected in Missouri and never found another Helenium virginicum?”
He has a hypothesis for that, backed by scientific literature: there is documented unintentional bias in herbarium collections. “Collectors tend to go back to the same place,” he explained.
Virginia sneezeweed makes the case for looking someplace new, to find something that may be hidden in plain sight.
