We have two subspecies of yellow lady’s slipper in our state. Small yellow lady’s slipper is the smaller variety, and it grows in our western and southern counties.
Jim Rathert
Yellow Lady’s Slipper
Cypripedium calceolus
Skin irritating
Other Common Name:
Small Yellow Lady's Slipper; Large Yellow Lady's Slipper; Lady's-Slipper Orchid
Family:
Orchidaceae (orchids)
Description:
A beautiful perennial orchid frequently growing in colonies. Flowers have three long, brown, twisted “flags” — the upright one being a sepal, the other two, on either side of the “slipper,” being two lateral petals. The bright yellow slipper, or lip, is a third, modified petal. The petal-like structure behind the lip is actually a pair of fused sepals. Thus there are 3 sepals and 3 petals. Blooms April–June. Leaves broad, prominently parallel-veined, clasp the stem, to 6 inches long, sharply pointed, hairy.
We have two subspecies in our state. Small yellow lady’s slipper (var. parviflorum) has a lip ¾–1 inch long, flags reddish purple to brown, and 4–6 leaves per stem; it grows in western and southern Missouri. Large yellow lady’s slipper (var. pubescens) has a lip 1–2¼ inches long, flags yellowish green with purplish streaks, and 3–4 leaves per stem; it grows in eastern Missouri.
Similar species: Two other species of lady’s slippers grow in Missouri; neither is yellow. Showy lady’s slipper (C. reginae) has white flowers with sepals and lateral petals that don’t twist; the lip is pink- or purple-tinged. Small white lady’s slipper (C. candidum) has flowers whose purplish or brown-tinged “flags” twist; the lip is white with purplish streaks on the inside surface. It is rare and found in only one location in extreme southern Missouri.
Size:
Height: to 2 feet (var. pubescens); var. parviflorum is shorter.
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Large Yellow Lady’s Slipper
Of the two subspecies of yellow lady’s slipper in our state, large yellow lady’s slipper is the larger variety, growing to 2 feet high; it grows in eastern Missouri.
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Large Yellow Lady’s Slipper
Yellow lady’s slipper is found statewide. It is among our showiest native orchids, and suffers from its popularity.
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Small Yellow Lady’s Slipper
Collecting orchids for gardening is the saddest reason for their decline in nature, since it's well-known that they nearly always die upon transplanting.
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Yellow Lady’s Slipper
There are 3 sepals and 3 petals on an orchid flower, but they are modified into unusual forms.
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Yellow Lady’s Slipper (Leaves)
On yellow lady's slipper, the number of leaves per stalk is one way to determining which subspecies a plant is.
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Yellow Lady's Slipper
Habitat and conservation:
Grows in upper and middle elevations of wooded slopes of ravines and stream valleys, facing north or east, in acid soils in rich upland forests.
Distribution in Missouri:
Scattered nearly statewide; absent from the Mississippi Lowlands. The smaller variety, parviflorum, grows in western and southern counties. The hairier and taller variety, pubescens, grows in eastern Missouri.
Status:
Most orchids are declining. Habitat destruction for logging, grazing, and conversion to pasture causes much of the loss. Root diggers also damage populations, selling the roots as medicinal herbs, even though the folkloric basis for thinking it useful as a drug hardly justifies wiping out these plants. Collecting orchids for gardening is perhaps the saddest reason for their decline, since it is no secret that lady’s slippers nearly always die upon transplanting.
Human connections:
Touching this plant can cause a skin rash in some people. Most orchids are declining, usually due to human activities. Cora Steyermark wrote, “Anyone who has any conception of the struggle an orchid must undergo to perpetuate itself would leave any member of this family in its natural habitat.”
Ecosystem connections:
Orchids are a pinnacle of the coevolution between flowers and pollinators. To acquire nectar, insects (mostly bees) must follow a labyrinthine obstacle course through the flower, providing the necessary cross-pollination in the process. Then, the seeds require a symbiotic fungus to survive.
Similar Species
Nodding Ladies’ Tresses
Spiranthes cernua
Adam and Eve Orchid
Aplectrum hyemale
Jack-in-the-Pulpit
Arisaema triphyllum
Green Dragon
Arisaema dracontium
Pale Touch-Me-Not (Jewelweed)
Impatiens pallida
Spotted Touch-Me-Not (Jewelweed)
Impatiens capensis
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!