SAN FRANCISCO — Scientists announced Monday the discovery of a rare — and stinky — orchid species that flourishes only in the wet meadows of a beloved portion of Yosemite National Park.

Botanist Alison Colwell said the species' minute, tennis-ball-yellow flowers weren't what first led her to it, but rather the smell of sweaty feet that the Yosemite bog-orchid emits to attract pollinators.

"I was out surveying clovers one afternoon, and I started smelling something. I was like, 'Eew, what's that?' " said Colwell, who works for the U.S. Geological Survey in El Portal.

The plant, which is the only known orchid species endemic to California's Sierra Nevada range, grows in spring-fed areas between 6,000 and 9,000 feet, Colwell said.

All nine sites where the orchid has been seen are in the park, some adjacent to areas popular among visitors, according to an article announcing the species' discovery published in Madroño, the journal of the California Botanical Society.

The species isn't likely to have any commercial value since its flowers are less than a quarter of an inch wide, but some orchid lovers were so enthused by the news that they began planning cross-country trips to see its delicate summer blooms.

"This orchid might not be showy enough to get the masses lined up all the way from San Francisco to see it, but I'm leaving Sunday to go out there to photograph it," said wild-orchid expert Paul Martin Brown, who planned to leave Acton, Maine, this weekend to include the orchid in his latest book.

Colwell, one of three scientists credited with the discovery, said the bog-orchid is thought to have persisted in the upland meadows south of Yosemite Valley, which nourished unique plant species because the area never froze under glacial cover.

At least seven other rare plant species have been found there, including the Yosemite onion, Yosemite woolly sunflower and Bolander's clover.

Park officials said they would not release details about where the plant was found because they were concerned visitors might love it to death.

"There's concern that it will get trampled," said ranger Adrienne Freeman. "It's a rare and precious resource that we want to protect."

A botanist named George Henry Grinnell collected the first Yosemite bog-orchid in 1923 and sent the dried, pressed flower to an herbarium that later gave its collections to Rancho Santa Ana Botanic Garden, Colwell said.

Ron Coleman, a visiting scientist at the garden, was combing through the collection one Friday morning in July 1993 when he found the original specimen on a herbarium sheet ringed with notes handwritten by Grinnell, who believed the flower was related to the green bog-orchid.

"It was just a little dry brown thing, but right away I saw several things about it didn't fit the pattern of any other orchid in California," Coleman said. "This discovery is not only personally satisfying but scientifically satisfying."

Coleman and his colleague Leon Glicenstein drove up to Yosemite the next day and rejoiced when they saw the flowers in the fading light. They snapped a photograph and sent it to orchid expert Charles Sheviak, hoping he would confirm their suspicion that the plant was a unique species.

Sheviak, curator of Botany at the New York State Museum, concluded the orchid was related to an existent variety that grows in the Rocky Mountains, but botanists familiar with Yosemite remained curious.

After Colwell — in her first year on the job — caught a whiff of the flower and was drawn to it in 2003, she called her boss, Peggy Moore. Together, they dug a plant from the meadow and sent it to Sheviak, who later revised his opinion.

The publication by Colwell, Moore and Sheviak on July 3 announcing the Platanthera yosemitensis, the Yosemite bog orchid's official name, made its status as a separate species official.

Orchids are the largest plant family in nature, with about 30,000 species worldwide.