This Rare, Endangered Orchid Only Exists in Two Locations. Can Dogs, Cows and Fungi Help It Thrive? A Smithsonian ecologist is trying to restore the plant, Spiranthes delitescens, which grows on Arizona’s sky islands Riley Black - Science Correspondent September 16, 2025 7:00 a.m. Ecological scent detection dog Circe searches for Canelo Hills ladies’ tresses in the tall vegetation Eirini Pajak At first glance, the orchid might seem like just another green wisp among the grass. Known to botanists as Canelo Hills ladies’ tresses and reclusive lady’s tresses, or Spiranthes delitescens, the plants’ stems grow up to a foot and a half tall and are dotted with tiny spikelike flowers. But these orchids don’t grow in just any fields. Canelo Hills ladies’ tresses are imperiled plants that pop up only in habitats so isolated by their elevation that naturalists call them “sky islands.” Because they are tied to specific environments, these orchids have always been rare. Now, their numbers are dwindling. Out of five locations in which Spiranthes delitescens has historically been found, she notes, the orchid is presently known to exist at only two, both in southern Arizona. To flourish again, the orchid needs help from humans and other organisms, including microscopic fungi, range cattle and specially trained dogs. Ecologist Melissa McCormick of the Smithsonian Environmental Research Center and the North American Orchid Conservation Center is among the scientists working to help the orchids recover. Part of the challenge in assisting Canelo Hills ladies’ tresses is where they grow. Named for the Canelo Hills Cienega Preserve, a Nature Conservancy wetland ecosystem intended to give them more places to take root, the orchid is found around rare water sources fed by springs in desert rock or in areas that otherwise are consistently moist enough for the plants. The habitats occur only in elevated locations above the desert floor, similar in composition but isolated from one another. Spiranthes delitescens, Canelo Hills ladies’ tresses orchid Eirini Pajak But moisture is only one of the orchid’s requirements. McCormick says that all orchids need associations with specific fungi. These fungal networks in the soil provide orchids with the nutrients they need to grow—an extremely close relationship that the plant maintains from seed through the rest of its life. Canelo Hills ladies’ tresses are particularly fussy about that relationship. “This orchid is very specific,” McCormick says. “It just needs one fungus and only one fungus species.” And that fungus is extremely difficult to find. She and her colleagues can’t just peek into the soil and see whether it’s present. This fungus, a species of Tulasnella, is detectable only through DNA sampled from the soil. The fungus is present in the two locations where the orchid grows. Both places are on privately owned cattle ranches. When the cows graze in these habitats, they trample other forms of vegetation and create hoofprints in the soil. Those hoofprints collect water, McCormick explains, which helps nourish the orchid and allows it to flower when the cattle are not present on the ranch. “It works just fine as long as the orchids are not flowering when the cows are there,” she says. Part of McCormick’s ongoing goal, however, is to find other locations where Spiranthes delitescens can grow. “While current populations are found only on private lands, it would be promising to see the species expand to public lands in the future,” says the Nature Conservancy’s stewardship program director, Erin Creekmur. Being able to easily study the orchid population on land dedicated to wildlife maintenance will help ensure the long-term survival of a species that, because of its stringent growing needs, has never been especially numerous. Researchers Melissa McCormick and Hope Brooks search for Canelo Hills ladies’ tresses in a cienega Eirini Pajak Fun fact: What are the sky islands of Arizona? These mountain ranges are elevated above the surrounding desert in the southeast area of the state. The orchid species Spiranthes delitescens grows in the rare wetlands of the sky island region. Melissa McCormick adjusting the focus of a video camera to record pollinators on the Canelo Hills ladies’ tresses orchid in the foreground Eirini Pajak Research on the orchid’s needs has led McCormick and colleagues to employ multiple techniques to better identify habitats that could support Spiranthes delitescens. A persistent supply of water, often from natural springs seeping from rock, is one consideration. The fungus is equally important. The areas where the orchid presently grows have the right fungus, McCormick notes, whereas tests of soil where the orchid used to grow have turned up less of the right fungus. Those areas might not be capable of hosting the plant right now. As the scientists expanded their search, they found places within the Canelo Hills preserve that contain the right fungus even if the plants themselves are not yet present. Now the researchers are getting ready to plant more than 10,000 orchids in these sweet spots. So far, researchers have planted 16 young orchids as a test. The next phase, after a controlled burn in the preserve to maintain vegetation, is a larger planting in multiple areas, including places where the orchid has not previously been found. Scent dog trainer Lauralea Oliver, pointing out areas for her dog, Muon, to search for orchids Eirini Pajak The pollinators the orchid requires are still little-known. As part of the planting initiative, McCormick and her fellow researchers have set up motion-sensitive cameras by some of the orchids to document which pollinators come to visit. So far, she says, these have mostly been bees, but a more definitive assessment is still underway. Canine assistants help keep track of how the orchids are faring. In previous surveys, McCormick says, “dogs were trained to key in on where this orchid is, visiting the existing populations and where the orchids used to be.” Dogs’ remarkable smelling abilities are important because the orchids are small and often hard to see, so a dog can smell what a human might step right over. The dogs found the orchids where they were known to be growing but did not in the places where the plant seems to have drawn back, and their skills will continue to be useful in monitoring where it’s appearing. Melissa McCormick looks on as ecological scent dog Circe receives her toy reward from trainer Lauralea Oliver Eirini Pajak The dedication to finding new ground for the orchid is about more than helping this single plant species. “The orchids are an indicator species of how the ecosystem is doing,” McCormick notes, and the conditions they need to survive are also important for various other plants, insects, fungi and associated organisms in the region. Caring for one plant ultimately means caring for an entire ecosystem. The orchid species may be small, but efforts to help these little plants grow will have reverberating effects for the other forms of life on the islands in the sky. Ecological scent detection dogs Muon and Circe enjoy a bit of downtime with trainer Lauralea Oliver, as Steve Blackwell of the Desert Botanical Garden walks ahead Eirini Pajak Get the latest on what's happening At the Smithsonian in your inbox.

A Smithsonian ecologist is trying to restore the plant, Spiranthes delitescens, which grows on Arizona’s sky islands