In a tamarack swamp in the vast woods east of Sandstone, two scientists from the University of Minnesota Landscape Arboretum and Rebecca Jeffrey, the property owner, ambled with downcast eyes, stepping through hummocks of thick sphagnum moss. They sought the seed pods of pink lady's-slippers. It was September, and fleshy orchid leaves lay decomposing on the moss in singles and pairs.

The scientists, David Remucal, curator of endangered plants at the arboretum, and his associate, Michael Monterusso, are on a mission to store seed from and grow all of Minnesota's 48 species of native orchids. After learning or developing methods to propagate the various types, the arboretum will be able to create populations of the orchids for display, for education, and potentially to supply fresh seed for restorations. Two years into the project, the scientists have collected seed from 33 of the species and germinated specimens of 21 species.

DNR botanists such as Hannah Texler support Remucal's work by helping him find rare orchid populations that are large enough to supply seeds for the project. "We expect to gain important information about why orchids grow where they do," said Texler, plant survey supervisor for the Department of Natural Resources' Minnesota Biological Survey.

A second part of the project uses a similar seed-banking and propagating approach for eight species of the rarest plants in the upper Midwest. Selected by the Center for Plant Conservation, a nonprofit that coordinates efforts of member arboretums, these endangered species include two orchids: the western prairie fringed orchid, a federal threatened species, and the ram's-head lady's-slipper, a state threatened species.

Back in the Jeffrey woods, Rebecca had led Remucal and Monterusso to the lady's-slipper patch via her sons' deer hunting trail.

"We want to save this stuff," Jeffrey said. "Everyone I've told—friends, neighbors—is really excited about you guys doing this."

"All orchids are rare, although some are rarer than others," wrote DNR botanist Welby Smith in Native Orchids of Minnesota. Ten of Minnesota's orchid species are listed as endangered, threatened, or of special concern. Oklahoma grass-pink, a diminutive prairie dweller, hasn't been seen in the state since 1884.

"People often refer to orchids as canaries in the coal mine," Remucal said. "There's a whole suite of things orchids need to survive."

Threats include climate change, invasive species, predation, poaching, loss of pollinators, herbicides, and altered hydrology caused by development. Orchid seeds require certain fungi living in the soil, which the seedling can parasitize.

The trio began finding seed pods on the brushy edge of the swamp. Monterusso twisted one grape-size pod free from its stem and, before placing it in a wax-paper packet, split the pod open with his thumbs. The seed looked like fine sawdust.

For these orchids, "The strategy is quantity, not quality," Monterusso said.

At his lab, Remucal stored the seed in a high-tech freezer. The seeds of some species will germinate in agar, a gelatinous growth medium made from algae that supplants the plants' needs for fungal partners. In a closet, tiny orchids grew from the agar in screw-top jars. An infant specimen of Loesel's twayblade resembled a grain of rice standing on roots like short lengths of spider silk.

When the plants turn green or develop leaves, Remucal will expose them to light. Showy orchis has resisted all propagation attempts. Nodding ladies' tresses, on the other hand, germinated in potting soil, even flowering in their second year, which raised questions about the species' fungal requirements. Outside the lab, in a hoop house sheathed in shade cloth, showy lady's-slippers in pots extended leaf pairs the size of chipmunk ears.

"Orchids are evocative to the imagination," Remucal said. "If we show people the plants, people are more likely to agree to keep these around for a long time."