Cypripedium guttatum is a medium-sized orchid of subalpine tundra and dry ridges with beautiful inflated, purple-spotted flowers. Quite rare in Denali, plants grow 10-20 cm tall from long rhizomes, sometimes found in dense clusters. Each plant has two stem leaves, alternate to subopposite, clasping the stem. The leaves are ovate to elliptic, 2-8 cm wide and 2-15 cm long. The whole plant is covered in minute hairs. The stem terminates in a single flower, with a leaf-like bract clasping the stem below the flower, upright like a collar. The flower is bilaterally symmetric with high specialized morphology, as in all orchids. The petals and sepals are white with red-purple blotches. The upper sepal forms a hood; the lower sepals are fused behind the lip, leaf-like. The large lip is inflated, sac-like, 2 cm long. The spotting and coloration of the flowers varies widely, even within local populations. The fruit is an ellipsoid capsule containing many minute seeds. Other local species of Cypripedium have more than two stem leaves. Another orchid species with solitary spotted flowers is Calypso bulbosa, but that species has only one leaf and different flower morphology (compare the photos).
Spotted lady's slipper flowers in June and July.
Cypripedium guttatum is monoecious with bisexual flowers. Pollinated by bees, this species is a deceptive orchid (Bänziger et al. 2005). Despite its showy flowers, it offers no reward of nectar or pollen. Instead, the bees attracted by its scent and color have to endure an ordeal: after climbing into the flower, they slip on the oily surface of the staminode, falling into the lip. To get out, they must crawl through a narrow exit, which allows the plant to attach its pollen to the bee's thorax. If the bee is foolish enough to try this twice, an orchid will be pollinated. Like all orchids, C. guttatum produces capsules containing hundreds of dust-like seeds, which are wind-dispersed. Seeds contain almost no food reserves for the embryo, and are dependent on mycorrhizae to germinate.
Spotted lady's slipper is cultivated as an ornamental flower.
Cypripedium guttatum is a widespread circumpolar species, occurring in North America and widely in Eurasia, from the Ural Mountains across Russia to Korea and Japan to the Himalayas. In North America, spotted lady's slipper has a limited distribution, occurring only in Alaska and neighboring areas of the Far North. This species occurs from the Aleutians through southcentral Alaska and a narrow band of central Alaska, across to northern Yukon and reaching its limit in central Northwest Territory. In Denali, this species only occurs in the northeastern corner of the Park, with a handful of specimens known from near the Teklanika Mountains and Park headquarters.
All the specimens from Denali were found in roughly the same area, on moderate slopes and in the lower-mid elevations. The fairly narrow range of altitudes is 459 to 785 m. There were slightly more specimens from southern slopes than northern, but this could be due to the small number of plants available.