Center for Biological Diversity

For Immediate Release, June 9, 2022


Robin Silver, (602) 799-3275,

Rare Southwest Wildflower Protected Under Endangered Species Act

Water Overuse, Livestock, Invasive Species, Climate Change Threaten Arizona Eryngo

TUCSON, Ariz.— In response to a petition from the Center for Biological Diversity and Maricopa Audubon Society, the U.S. Fish and Wildlife Service today protected the Arizona eryngo under the Endangered Species Act. Only four populations of the critically imperiled wetland plant survive in Arizona and Mexico.

The Service also designated nearly 13 acres of critical habitat for the plant at La Cebadilla, east of Tucson, and Lewis Spring in the San Pedro National Riparian Conservation Area. It excluded Pima County’s Agua Caliente Park because reintroduction efforts there appear to have failed.

“I’m so glad these big, beautiful plants and the rare cienega habitats where they live are getting these badly needed protections,” said Robin Silver, a cofounder and board member at the Center. “The eryngo gives us one more reason to save the San Pedro River.”

Arizona eryngo plants along the San Pedro River are imperiled as the groundwater table connected to the plant’s wetland habitats is lowered by pumping. The groundwater overdraft in the Fort Huachuca-Sierra Vista loses more than 5,000 acre-feet per year. All recent hydrology studies predict the San Pedro Riparian National Conservation Area will disappear if the unsustainable water drawing continues.

More than 95% of the cienega habitats that the eryngo and many other species need to survive have already been lost. Both sites where the flower survives are threatened by groundwater overuse to support sprawling human populations. The eryngo used to be found at one site in New Mexico but is now gone from the state.

“Arizona eryngo is a bellwether for the San Pedro River,” said Silver. “We can’t keep withdrawing more groundwater than is returned in Sierra Vista, or anywhere else in Arizona, and expect these irreplaceable and imperiled species to survive.”

Arizona eryngo is in the carrot family and can grow to more than 5 feet tall, with large, cream-colored spherical flowers. It is also called ribbonleaf button snakeroot, and its scientific name is Eryngium sparganophyllum. The Arizona Native Plant Advisory Group ranks Arizona eryngo as one of the most endangered plants in the state.

Arizona Eryngo visited by a tiny checkerspot butterfly. Credit: Elizabeth Makings. Image is available for media use.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.7 million members and online activists dedicated to the protection of endangered species and wild places.

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