Botanists have dug up some of Utah's rarest flowers and moved them to an arboretum at Flagstaff, Ariz., in hopes of ensuring the species will not be lost if the wild population is killed, officials say.

Up to four "autumn buttercups," once believed to be extinct, were moved last week from a pasture near Panguitch in southern Utah to the Arboretum at Flagstaff, said Larry England, a botanist for the U.S. Fish and Wildlife Service.The buttercup, England said, was recently found growing in a tiny marshy area in the pasture. It was difficult to determine how many of the plants exist because all the leaves had been devoured by rodents, he said.

"This is an insurance move more than anything else," England said. "We wanted to move between one-quarter and one-third of the population."

The botanist said it is hoped the captive plants can be grown to reproduce enough individuals for a reintroduction effort.

One of two plants died last summer after it was moved to the private, non-profit arboretum to determine whether the buttercup can survive in potting soil and greenhouse conditions. Apparently not enough root mass was dug up, he said.

Now that botanists know the plants will survive in captivity, the challenge is to get the plants to produce seeds, said Ken Asplund, director of the arboretum's living collections.

Wire cages have been placed around the remaining wild plants to prevent cattle, believed to be one of the causes of the buttercup's decline, from trampling or eating them, England said.