Small White Lady’s Slipper

Species of Conservation Concern
Scientific Name
Cypripedium candidum
Orchidaceae (orchids)

Missouri has three species of native lady’s slipper orchids. Small white lady’s slipper is the one with white “slippers,” which are shiny and look almost like glazed porcelain. Today, it’s known from only one location in the Ozarks.

Small white lady’s slipper is the smallest of our lady’s slipper orchids, blooming at 6–16 inches tall. The stems are sparsely hairy, with usually 1 flower (sometimes 2) per stem. The leaves are 3 or 4 per stem, 2–5 inches long , less than 1½ inches wide, narrowly elliptic, sparsely hairy to smooth. The flowers have the typical lady’s slipper configuration with the lower lip forming an inflated pouch, like the toe of a ballet slipper, and the lateral (side) petals and upper sepal spirally twisted. The pouch (lip) is white, about ¾ inch long, with reddish purple streaks on the inside surface and around the opening. The twisted portions of the flower are yellowish green with varying degrees of reddish purple to brown tinging or streaks. Blooms April–June.

Similar species: Two other species of lady’s slippers grow in Missouri; neither is white, and both, though rarely seen, are still more common than small white lady’s slipper. Yellow lady’s slipper (C. calceolus) has yellow flowers and 3 brown twisted “flags.” Showy lady’s slipper (C. reginae) has white sepals and lateral petals that don’t twist; the inflated lip is pink- or purple-tinged.

Other Common Names
White Lady’s Slipper
White Lady Slipper Orchid

Height: 6–16 inches at flowering time.

Where To Find

Uncommon, currently known from only a single site in Howell County. Known historically also from extreme northwest Missouri, Shannon County, and the St. Louis area. The overall range includes the northeastern United States and adjacent Canada west to Nebraska; it is most common around the Great Lakes.

Occurs on seepy ledges and sheltered, lower slopes of ravines in mesic (moist) upland forests. Formerly known from northwest Missouri in seepy areas of mesic (moist) upland prairies, often in loess soils. The single known current location is on a seepy ledge of a dolomite bluff in Howell County. Perhaps more populations may be discovered, but the plants are easily overlooked unless they are flowering.

Native perennial wildflower. A Missouri species of conservation concern, ranked as critically imperiled. It is extremely rare, and very steep population declines have made it especially vulnerable to extirpation from the state. Indeed, it was thought to have disappeared from the state until fairly recently.

For many years, the last known location of this species in Missouri was on a west-facing slope in Nodaway County (northwest Missouri), and that population — of 15 plants — had last been seen in 1947. Attempts to relocate that colony have failed ever since. The small population that was more recently discovered, in Howell County, grows in a remote, rugged area alongside a colony of showy lady’s slipper. The white lady’s slippers in that location had been overlooked by botanists for many years because the small white lady's slipper plants were past flowering by the time the showy lady’s slippers were blooming.

If you find white lady’s slipper growing in the state, leave them alone, and please report it to the Missouri Department of Conservation.

This species is considered rare, vulnerable, imperiled, threatened, or endangered in many of the states and provinces where it occurs. This species rarely sets viable seed, and the tiny seeds (as with other orchids) contain little stored nutrients; thus they rely on the lucky presence of the right kind of symbiotic fungi at the germination site in order to survive.

Habitat disturbances are another reason for decline. This species is sensitive to being shaded out by invasive species, to being overgrown by native vegetation due to fire suppression, to losing its symbiotic fungi due to changes to soil moisture, and to habitat obliteration due to agriculture and development. When a population of these orchids is wiped out, as a general rule, it never comes back.

These lovely, small lady’s slippers were dug up by collectors for many years, and collecting pressure and loss of habitat caused this species to disappear in many places throughout the United States. Orchids usually do not survive transplanting, so uprooting them is usually a death sentence for them. If you are interested in growing orchids, learn how to grow the tropical epiphytic species that are propagated and sold in garden centers.

The genus name, Cypripedium, comes from Greek and Latin references to the goddess of love (Aphrodite or Venus) and “sandal.” The species name, candidum, means “white.”

In her memoir, Behind the Scenes, Cora Steyermark described her discovery of one of Missouri’s few populations of small white lady’s slipper. She and her husband, the botanist Julian Steyermark, had spent the whole day tramping over hills and bottoms without any luck. Cora started back to their camp earlier. Avoiding another exhausting uphill and downhill, she stuck to a mid-elevation route and ended up finding the colony where they least expected it, about halfway up a big hill. The flowers were beautiful: “The white of the slipper resembles white china more than anything else I can think of.” She shouted to get Julian’s attention. They had been looking for the plants at the bases of slopes, so they were surprised to see them so high up a hill. But where the orchids were growing, the soil was underlain by a layer of hardpan clay, which created a place where the soil didn’t drain easily. The orchids were growing in a perfect microhabitat with extra moist oil, halfway up the hill. This discovery was in the mid-1940s. Unfortunately, despite many attempts to relocate this colony since then, it has apparently disappeared.

Like many other orchids, lady’s slippers have evolved a kind of funhouse route for their pollinators to run through, all the better for ensuring cross-pollination with another flower. The insects enter the pouchlike lip and can only exit through smaller openings on the side. The pollinators for this species are certain types of smaller bees, including native andrenids (miner bees), halictids and lasioglossum bees (sweat bees), and ceratina bees (small sweat bees). As the bees fumble around in the flower, the flower’s anatomy forces them to rub against the stigma (depositing a previous flower’s pollen onto it) and the anthers (acquiring more pollen to deliver to the next flower). One study showed it can take a pollinator 15 minutes before it figures out how to exit the flower. The flower rewards the bee with nectar and pollen.

In addition to the amazing interactions with their pollinators, orchids also have a necessary relationship with their mycorrhizal fungi. These fungi live in the soil and attach to the orchid’s roots from the earliest moments of germination. The fungi help the orchid obtain nutrients and moisture throughout the life of the orchid, and orchids generally can’t live without them. This is why orchids are so difficult to transplant or raise from seed: the plants and their fungi must both survive together, and they both have exacting moisture, soil, and other habitat requirements.

Media Gallery
Similar Species
About Wildflowers, Grasses and Other Nonwoody Plants in Missouri
A very simple way of thinking about the green world is to divide the vascular plants into two groups: woody and nonwoody (or herbaceous). But this is an artificial division; many plant families include some species that are woody and some that are not. The diversity of nonwoody vascular plants is staggering! Think of all the ferns, grasses, sedges, lilies, peas, sunflowers, nightshades, milkweeds, mustards, mints, and mallows — weeds and wildflowers — and many more!