Indiana's Lady's Slippers

I had the good fortune this spring of seeing all of Indiana's naturally occurring lady's slipper orchids (Cypripedium spp.), save the hybrids. Four of the five species were observed in Indiana, with the fifth observed in Wisconsin.

Translated, Cypripedium means either foot or sandal of Cypris, the goddess of love and beauty. Although Indiana is home to five species in this genus, there are approximately 50 species of Cypripedium worldwide, all distributed in the Northern Hemisphere in temperate or colder climates. Within North America, only Nevada, Florida, and Hawaii have the misfortune of having no naturally occurring lady's slipper orchids.


Cypripedium acaule, Pink Lady's Slipper (also commonly called Moccasin Flower), is the only species in the genus with basal leaves and a leafless stem. As with other lady's slipper orchids, this species has a distinctly saccate lip (the "slipper").

Although I observed this species in LaPorte County, Indiana this spring, these photographs were taken in Carlton County, Minnesota, as my Indiana photos of Pink Lady's Slipper didn't come out so good as a result of poor lighting due to an impending storm.


Pink Lady's Slipper grows in acidic soils, whether they be in bogs or in dry conifer and oak woodlands. I remember being shocked to see this species years ago in Rhode Island on a dry sandy bank next to a parking lot, growing in a dense duff layer of pine needles. Prior to that, I had only seen it in a bog. Since that time, I've seen the species in a range of moisture conditions, but always in very acidic conditions. Cypripedium acaule can be found througout the eastern United States as far south as Alabama and Georgia, and into Canada as far north and west as the Northwest Territories. However, in the United States, it is mostly restricted to New England, the Appalachians, and areas surrounding the Great Lakes.


Unlike the previous species, Cypripedium candidum (White Lady's Slipper) grows in alkaline conditions, on calcareous substrates, often in organic soils. It can most commonly be found in Indiana in fens and sedge meadows, but it also is found in marshes and prairies. Prior to the conversion of prairies to agricultural fields, White Lady's Slippper was much more abundant, as it primarily occurred in calcareous prairies in Illinois and Indiana. I've also seen this species growing on a dolomite glade in Missouri.

The flowers of Cypripedium candidum begin to form when the plant is still emerging from the ground in the spring. During and after anthesis, the plants continue to grow, resulting in much taller plants (up to about 1.5 feet) later in the season. Even at that height, after flowering, White Lady's Slipper plants can be difficult to find amongst the dense vegetation that surrounds them in prairies and fens in the late spring/early summer.


White Lady's Slipper is found mostly in the upper Midwest, with its greatest distributional density clustered around the Great Lakes and the border between Minnesota and the Dakotas. Disjunct populations also exist as far away as New York, Pennsylvania, West Virginia, Kentucky, Alabama, Missouri, and Nebraska. These photographs were taken in the sedge meadow portion of a fen in northwest Indiana, where this species and the next grew in close association.


Cypripedium parviflorum var. makasin, Small Yellow Lady's Slipper, is probably the least common of Indiana's five lady's slipper species. Its lips are smaller and generally shinier than those of the following species, and its petals and sepals are a deep maroon color. Hybrids between this species and the previous are called Cypripedium x andrewsii, Andrews' Lady's Slipper.


Once known as Cypripedium calceolus var. parviflorum, this lady's slipper is only found in the northern half of Indiana, where it grows primarily in fens and calcareous swales in the dune-swale community in the northwestern portion of the state. Its North American distribution includes New England, areas around the Great Lakes, and a band stretching through Canada and into Alaska. It also extends south through western Canada and into Montana and Washington, with disjunct populations in California, Colorado, and Utah.


With a larger floral lip and petals and sepals that are yellowish green (sometimes with purple blotches or lines), Cypripedium parviflorum var. pubescens, or Large Yellow Lady's Slipper, usually seems different enough to consider it a separate species from the previous as opposed to just a different variety of the same species. However, the two are said to intergrade frequently in areas where their ranges and habitats overlap. Cypripedium parviflorum var. pubescens is found throughout much of eastern North America, as well as within the Rocky Mountain range, with a few disjunct populations as far south as Arizona, New Mexico, and Texas.


Previously known as Cypripedium calceolus var. pubescens, Large Yellow Lady's Slipper, the most common lady's slipper in Indiana, eluded me this year within Indiana, but I saw it blooming in Superior, Wisconsin. Habitats in which this orchid can be found include mesic forests, dry-mesic forests, thickets, hill prairies, and seepy wetlands with high groundwater. It rarely hybridizes with Cypripedium candidum, in which case the hybrid can be called Cypripedium x favillianum, Faville's Lady's Slipper.


The final lady's slipper that I saw this spring was observed in a fen in LaPorte County, Indiana. I was a bit late, so only two of the plants in this fairly dense population of Cypripedium reginae (the aptly named Showy Lady's Slipper) were still displaying flowers. This is the largest of the Cypripedium in Indiana, growing to nearly 3 feet tall with a lip 1-2 inches long.


Within Indiana, the range of Cypripedium reginae is restricted to the northern half of the state. This is because of the limited distribution of the fens, seeps, and swales in which it grows. It was said to once grow by the thousands in the area that is now downtown Gary, Indiana. Hard to picture. Its North American range centers mostly around the New England and Great Lakes states and provinces, with outlier populations as far away as North Carolina, Arkansas, Missouri, North Dakota, and Saskatchewan.