SEBASTOPOL -- Did someone in this wine country town illegally plant an endangered flower to sabotage a proposed housing development? That is the question at the center of a quarrel folks here have dubbed "Foamgate."

Bob Evans, a 72-year-old retired elementary school principal, says he was walking with his dog last year when he came upon the tiny white flowers of Sebastopol meadowfoam poking from shallow pools of water in a grassy field.

The former bean farm happens to be the site chosen for the 20-acre Laguna Vista housing development.

Evans and other opponents seized on the discovery of the federally protected species in hopes it would force the developer to scale back plans for 145 houses and apartments. "It was the bad luck of the developer that it popped up," Evans said.

But state wildlife officials investigated and concluded that the meadowfoam had been transplanted there. They ordered it dug up.

This year, the flowers returned, and with them the controversy. The dispute has held up final approval of the building project.

Sebastopol, a well-to-do community of about 8,000 people 50 miles north of San Francisco, is known for its environmentally conscious residents and restrictive growth policies.

"Our community takes a very hard, careful look at development," said Kenyon Webster, the town's planning director. "That small-town character is the reason a lot of people want to live here."

When the meadowfoam appeared in April 2005, and the Department of Fish and Game determined it had been planted, it appeared to be the work of zealous conservationists.

"The people who planted it mistakenly believed that it would be the silver bullet that killed the project," said Scott Schellinger of Schellinger Brothers, the developer behind Laguna Vista.

Known as Limnanthes vinculans, the herbs grow up to a foot tall and have small bowl-shaped white flowers. They are only found in seasonal wetlands and pools created by spring rains in this part of Sonoma County.

Threatened by agriculture and urban development, the meadowfoam is listed as an endangered species by the state and federal governments. That makes it illegal to harm, remove or transplant them without permission. Wetlands and pools have been set aside to protect them.

Evans and other conservationists say the $70 million development could damage the nearby Laguna de Santa Rosa, a 240-square-mile basin of wetlands that runs through Sebastopol.

Evans called Sonoma State University biology professor Phil Northen and the head of the local chapter of the California Native Plant Society. They visited the site and agreed the plants were native.

Northen, who does not live in Sebastopol, said that the field was "perfect habitat" for meadowfoam, and that there was no evidence the flowers had been planted.

But when a Fish and Game team visited the site at Schellinger's invitation a few weeks later, it reached the opposite conclusion.

Eric Larsen, the department's deputy regional manager, said the flowers had never before been seen at the site, which is at a higher elevation than the typical meadowfoam habitat. Team members also noticed plants beneath the meadowfoam, leading them to believe it had been transplanted.

"They didn't belong there," Larsen said.

If the plants had been found to be indigenous, it could have triggered another round of environmental studies and forced the developer to reconfigure the project.

Fish and Game launched an investigation into who planted the flowers but never identified any suspects. The department interviewed Evans and Northen, but Larsen said the case went cold.

Foamgate might have ended there, had the flowers not sprouted again in recent months in the same area.

Schellinger said the new plants grew from seeds scattered during the "original criminal act." Fish and Game agreed.

Still, the City Council tabled final approval of Laguna Vista on May 22. A mediator is now overseeing negotiations between Schellinger Brothers and residents in hopes of reaching a compromise that could involve a scaled-down version of the project.