The University of Wyoming is part of a collaboration that has identified 65 extinct plants in North America.
North Carolina Natural Heritage botanist Wes Knapp said to begin, it's hard to determine if a plant is extinct.
"There was a study about how things are expected to change over the next hundred years in terms of extinction," said Knapp. "I realized we expect things to change but we don't know how they are going to change because we don't know what's already extinct."
He said to find extinct plants, they looked for historical records and made sure no one had found them recently.
"Every one of these things we're saying is extinct has been searched for and not found. I personally hope every one of them is rediscovered," said Knapp. "Maybe the botanical community will take some of them as challenges, but at this time, the best data argues that all of these things are gone."
Lead botanist at the Wyoming Natural Diversity Database Bonnie Heidel said one of the plants the group identified was the Yellowstone rockcress.
"Aven Nelson discovered it in 1899 in Yellowstone National Park," she said. "It's not been seen since."
The study suggests that this is an extreme underestimate for how many plants have gone extinct.
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