Discovery in bloom: Professor Laary Cushman helps unearth an Ice Age relic in upstate South Carolina
Poking through the soil, the gentle, delicate flower is almost indistinguishable from the flora all around it. With green, pointy leaves surrounding a wispy stem atop which sits a white, red-ringed bloom, the plant looks at home in Upstate South Carolina.
Except it’s not. By all accounts, it shouldn’t be here on a granite outcrop at Nine Times Preserve in northern Pickens County. That’s part of what makes this flower so unique. So unique, in fact, it may not exist anywhere else in the world.
And Dr. Laary Cushman, a professor in the Anderson University College of Arts and Sciences, is among those who found it.
It’s called Shealy’s Saxifrage, a type of flowering plant that is considered a relic from the last Ice Age when more of a tundra- like habitat existed in Upstate South Carolina. Similar plant populations are found in higher elevations of the southern Appalachians, Dr. Cushman said, but this particular plant is unique because it’s in a relatively low elevation.
The findings of Dr. Cushman, along with colleagues Dr. Patrick McMillan and Dr. Vincent Richards, both professors at Clemson University, were published in the journal Phytotaxa. McMillan called on Dr. Cushman to perform a species content study for the plant, which blooms from late winter to early spring.
Dr. Cushman, who teaches biology at AU, said Shealy’s Saxifrage migrated at the end of the last Ice Age.
When the glaciers receded and we started to see climate change occur, these plants had to find some place to live. Because these plants can’t exactly pick up roots and move like animals and because they weren’t able to migrate northward from our area, they were able to move up higher,” Cushman said.
The plant has been named Shealy’s Saxifrage in honor of Dr. Harry E. Shealy Jr., professor emeritus at USC-Aiken, known for his contributions to botany and also an adviser of Dr. Cushman in his master’s and doctoral work on speciation.
“We did a species concept study, experimenting to evaluate whether or not these plants meet the idea or qualifications for a new species,” Cushman said. “Traditionally we want to complement these studies so they can verify or validate each other, so we chose the biological, phylogenetic and ecological concepts. The biological concept is that if it’s a unique species, it can’t breed with anything else; that population is isolated from all other sister plants. The environmental species concept says that this species occupies a unique environment opposed to all other plants. The phylogenetic concept says there’s enough genetic variation between this population and other populations that makes it a new species.”
"It’s called Shealy’s Saxifrage, a type of flowering plant that is considered a relic from the last Ice Age when more of a tundra-like habitat existed in Upstate South Carolina."
— Dr. Laary Cushman
AU Biology Professor
In other words, Dr. Cushman’s team wanted to know whether Shealy’s Saxifrage is an entirely new species or simply a different variety of a known species. Biologically and ecologically, Dr. Cushman found that Shealy’s Saxifrage met the definition of new species. But it did not meet the phylogenetic standard. That’s why Shealy’s Saxifrage is treated as a variety, or new form, in the botanical kingdom.
“It’s a late winter-early spring bloomer where all these other plants begin blooming in early summer all through to early autumn. Then the ecological species concept says it’s a low elevation site. The microclimate was different from the high elevation sites, so it met that concept. But we didn’t get enough resolution in that there’s a genetic difference between the two populations. That’s why we approached it from the variety, just to get the attention of the scientific community,” Cushman said.
“What’s neat is that in South Carolina you can see remnants of past environments,” Dr. Cushman said. “The initial thought of this Nine Times population is that it was widespread throughout this entire area, but as the climate changed you start to see warmer vegetation creep in and the colder vegetation just migrated to higher elevations. They became disjunct (disjoined) from other major populations.”
The Nature Conservancy owns and manages Nine Times Preserve, which lies at the intersection of the Southern Blue Ridge Mountains and the Piedmont region of South Carolina.
Dr. Laary Cushman is an AU biology professor from the College of Arts and Sciences and the co-founder of Shealy's Saxifrage.