This is one of the largest and most attractive orchids in Illinois. It is more abundant than most species of orchid, although by no means common. While the flowers are in bloom, it is easy to identify this plant as a Cypripedium sp. (Lady's Slipper Orchid) because of the slipper-like lower petals. The only other species that it can be confused with, Cypripedium parviflorum (Small Yellow Lady's Slipper Orchid), has similar flowers that are smaller in size. The lateral petals of its flowers are less than 2' long, while the slipper-like lower petal is about ¾–1¼' in length. The flowers of this species are more likely to be fragrant. The Small Yellow Lady's Slipper Orchid usually has a pair of leaves toward the base of the central stem, while Yellow Lady's Slipper Orchid usually has 3-6 leaves along the central stem. When this latter orchid is not in flower, it can superficially resemble Polygonatum commutatum (Solomon's Seal) and similar species in the Lily family. However, the central stem of this orchid and the upper surface of its leaves are pubescent, while the latter group of plants has stems and upper leaf surfaces that are waxy and glabrous.

This native perennial plant is 1–2½' tall and usually unbranched. The central stem is round in circumference, rather stout, and densely covered with hair. Three or more leaves alternate along this stem. These leaves are up to 6' long and 4' across. They are oval-ovate, smooth along the margins, and pubescent. Parallel veins are readily observable along the upper surface of each leaf. The base of each leaf clasps the stem. The color of the foliage can vary from dark green to yellowish green, depending on growing conditions and the maturity of the plant. The central stem terminates in 1 or 2 flowers. Each flower is held above the foliage on a long stalk that has a single leafy bract behind the flower. This bract resembles the leaves, but it is smaller in size. Like other orchids, each flower has 3 petals and 3 sepals. However, because two of these sepals are fused together, there appears to be only 2 sepals. The lower petal is in the shape of a slipper or a pouch with an opening on top; it is bright yellow, shiny, and 1¼–2' in length. Within the interior of this petal, there are frequently reddish brown dots. The 2 lateral petals are narrow, more or less twisted, and 2–3¼' in length. They vary in color from greenish yellow to brownish purple and have fine veins running from the base of the flower to their tips. The sepals form an upper hood and a lower hood. They are broader and shorter than the lateral petals, otherwise their appearance is similar. The reproductive organs are located toward the posterior of the slipper-like lower petal. The blooming period occurs from late spring to early summer and lasts about 3 weeks. There is usually no noticeable floral scent. If a flower is successfully pollinated by insects (often this doesn't occur), it will form a sack of fine seeds; these seeds are easily carried aloft by the wind. The root system consists of a tuft of fleshy fibrous roots. When several plants occur together, they are often vegetative offsets of the mother plant.

Yellow Lady's Slipper Orchid is an uncommon plant that is widely scattered across Illinois (see Distribution Map). It is less common than formerly, but still persists in small colonies at several sites. Habitats include mesic to dry deciduous woodlands, sandy woodlands and savannas, thinly wooded bluffs along rivers, and shady areas of bogs. The size of local populations can increase in response to fallen trees or occasional wildfires, as this reduces excessive shade from woody vegetation. Some authorities regard this orchid as a native variety of Cypripedium calceolus, which occurs in Eurasia. Under this system of classification, its scientific name is Cypripedium calceolus pubescens.

Cypripedium calceolus var. planipetalum (Fernald) Vict. & J. Rousseau:
Canada (North America)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Cypripedium pubescens Willd.:
Canada (North America)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Widespread in Canada and the United States. Alaska to Newfoundland, south to Oregon, northern Idaho, eastern North Dakota, Louisiana, and Georgia, with disjunct populations in the Rocky Mountains from Wyoming to New Mexico and Texas.

C. calceolus var. parviflorum may be easily differentiated from var. pubescens by its small leaf, lip, and plant size, leaf shape, degree of twisting in lateral sepals, sepal color, and habitat preference.

Possible type for Cypripedium veganum Cockerell et al.
Catalog Number: US 404899
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined
Sex/Stage: ; Flowering
Preparation: Pressed specimen
Collector(s): P. Barker & M. Barker
Year Collected: 1901
Locality: New Mexico, United States, North America

Yellow Lady's Slipper Orchid is an uncommon plant that is widely scattered across Illinois (see Distribution Map). It is less common than formerly, but still persists in small colonies at several sites. Habitats include mesic to dry deciduous woodlands, sandy woodlands and savannas, thinly wooded bluffs along rivers, and shady areas of bogs. The size of local populations can increase in response to fallen trees or occasional wildfires, as this reduces excessive shade from woody vegetation. Some authorities regard this orchid as a native variety of Cypripedium calceolus, which occurs in Eurasia. Under this system of classification, its scientific name is Cypripedium calceolus pubescens.

Comments: Cypripedium parviflorum var. pubescens grows in boggy areas, swampy areas, damp woods (often with a rich layer of humus and decaying leaf litter), near rivers or canal banks (Great Plains Floral Association 1986, Swink and Wilhelm 1994, Weber and Wittmann 1996, Hulten 1968, Cronquist et al. 1972), and in wet meadows (in the Pacific Northwest) (Welsh et al. 1993). In Kentucky it is reported from dry mesic woods and occasionally associated with open glades (Kentucky Natural Heritage Program).

It has also been associated with rocky wooded hillsides on north or east facing slopes, wooded loess river bluffs, and moist creeksides or swales in spruce zones. Soils are sandy loams to loams.

The showy flowers attract small bees and various flies. Charles Robertson observed Ceratina spp. (Little Carpenter bees) visiting the flowers, although he did not consider them to be effective at pollination. Herman Müller observed Andrenid bees pollinating the flowers of Cypripedium calceolus (a very similar orchid in Eurasia). He also observed various flies visiting the flowers, but they were ineffective at pollination. Müller claimed that the flowers occasionally produce small amounts of nectar as a reward, but other authorities dispute this. White-Tailed Deer readily consume the foliage of this and other orchids, and local populations may require a deer-resistant fence for protection where these animals are abundant.

Cypripedium pubescens (Yellow Lady's Slipper)
(Insects are lured to the flower of this orchid by deception, as it provides neither nectar nor accessible pollen; some bees were successful pollinators of the flowers, while other bees did not carry any pollinia; flies and beetles were not successful pollinators; some insects became trapped in the flowers and died, or they were killed by lurking spirders; observations are from Robertson and Stoutamire as indicated below; because Stoutamire does not always distinguish between Cypripedium pubescens and Cyrpipedium parviflora, some of his observations are applicable to the latter orchid)

Bees (long-tongued)
Apidae (Apinae): Apis mellifera exp (Stm); Anthophoridae (Ceratinini): Ceratina calcarata exp (Rb, Stm), Ceratina dupla dupla exp dead np (Rb, Stm); Megachilidae (Osmiini): Osmia sp. dead np (Stm), Osmia pumila exp (Stm)

Bees (short-tongued)
Halictidae (Halictinae): Agapostemon splendens exp (Stm), Halictus rubicunda dead np (Stm), Lasioglossum coriaceus dead np (Stm), Lasioglossum pectoralis exp np (Stm), Lasioglossum pilosus pilosus exp np (Stm); Andrenidae (Andreninae): Andrena nivalis dead np (Stm)

Flies
Syrphidae: Eristalis dimidiatus dead np (Stm); Stratiomyidae: Odontomyia interrupta exp np (Stm); Conopidae: Zodion fulvifrons dead np (Stm)

Beetles
Buprestidae: Anthaxia inornata dead np (Stm)

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: Thousands of populations are probably extant rangewide. Michigan: common, not tracked (Michigan Natural Features Inventory); Indiana: not common, not tracked (Indiana Natural Heritage Data Center); Manitoba: >100 (Manitoba Conservation Data Centre); Texas: one historic occurrence reported in 1929 (a collection from the shore of a playa lake in Bailey County) but not seen since then-record may be erroneous (Texas Conservation Data Center), and is considered so by Kartesz (1999); Kansas: about 30 (Kansas Natural Features Inventory); Idaho: 4, all limited in extent (Idaho Conservation Data Center); Wyoming: 9 (2 historical) (Wyoming Natural Diversity Database); Mississippi: 27 (Mississippi Natural Heritage Program); New Mexico: 8 (New Mexico Natural Heritage Program); Georgia: 23 reported, hundreds likely (Georgia Natural Heritage Program); Vermont: 25 (Vermont Nongame and Natural Heritage); Colorado: 28 (Colorado Natural Heritage Program); Delaware: 2 (Delaware Natural Heritage Program); New Hampshire: 9 current and 10 historical (New Hampshire Natural Heritage Inventory); South Dakota: 23, mostly in Black Hills (South Dakota Natural Heritage Database); Arizona: 6 (in White Mountains)-Ron Coleman, an expert on the orchids of Arizona, has failed to relocate two of the occurrences during several trips, and it is believed that they have been extirpated due to trampling and collecting (Sue Schuetze pers. comm.).

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N4 - Apparently Secure

Rounded Global Status Rank: T5 - Secure

Reasons: Although there may be far more than a thousand populations of this species throughout its extensive range, most are small, and Cypripedium parviflorum var. pubescens (Cypripedium pubescens), when treated taxonomically to exclude the more widespread var. makasin (as by Kartesz, 1999) is clearly vulnerable to habitat loss, horticultural collecting, and medicinal collecting rangewide. There are very few reports of large, demonstrably secure populations anywhere in North America. All reported populations contain less than 400 individuals, and most contain less than 30. There are numerous threats to this species and its habitats, and the typically small populations of this species are highly vulnerable to extirpation. Extirpation of two populations has been documented in Arizona, and it is likely that many others have been recently extirpated. Despite efforts to protect this species from collectors, it continues to be impacted by this practice. Though quantitative data is not available at this time, available information suggests that this species is still in decline, and further measures to protect it should be implemented.

Global Short Term Trend: Decline of 10-30%

Comments: The habitat of Cypripedium parviflorum var. pubescens has certainly declined since European settlement of North America began. Forests have been cut. Wetlands have been drained. It is likely that Cypripedium parviflorum var. pubescens has incurred simultaneous population loss, the amount of which partly reflecting the localized habitat losses. It is likely that populations have been and continue to be impacted, at least locally, by collectors for the plant trade and by gardeners. This species was reportedly far more abundant historically in northeastern South Dakota (David Ode pers. comm.).

Comments: This species is threatened by plant collectors (presumably for gardens) and by habitat loss within parts of its range.

Of the several varieties of Cypripedium, C. calceolus var. parviflorum is the usual source for dried roots (Frontier Co-op 2000). After an industry resolution was passed in 1988 to discontinue sales of wild-collected lady's slipper root, many responsible herb companies complied. However, some companies persist in selling it (Frontier Co-op 2000). In addition, although many herb companies have agreed not to sell any Cypripedium material, some large companies continue to pay root diggers for rhizomes (Robyn Klein pers. comm.).

This species is reportedly very difficult to cultivate. It is "considered to be a semi-parasitic species and must be grown in very controlled conditions and is not economically feasible." (Ed Fletcher pers. comm.). Recently, the native plant nursery industry has successfully propagated it and considers it not technically difficult to grow in gardens (Rolf Schilling pers. comm. 2007).

Many orchid species have a reputation for difficulty of cultivation, which may be one reason that wild populations tend to be targeted for harvesting. An internet site contained the following general information on this species: "While commercially propagated plants are available, the quantities and prices do not support cultivation for the dried herb market. Dried lady's slipper roots currently being sold are likely wildcrafted roots, roots of other plants, or roots which have been dug in the wild and replanted in order to be called cultivated." (Frontier Co-op 2000)

It is reportedly cultivated somewhere by tissue culture for ornamental uses (Tim Smith pers. comm.). Small scale cultivation for the horticulture trade is reported from Manitoba, but this involves gathering plants from the wild and transplanting them in nurseries. Techniques for propagating this species from seeds involve germinating them on agar and then transplanting them to soil, but these have not been perfected yet (Elizabeth Punter pers. comm.).

Because the roots of this species are being sold in the medicinal herb trade [and cultivation is perceived to be very difficult] it is certainly being collected from somewhere (Mike Homoya pers. comm.).

Like other orchid species, some populations have been reduced over the years by collecting for gardens (Weber and Wittmann 1996).

In Kentucky, Deborah White (pers. comm.) has received anecdotal information that all lady's slippers are being collected, and has received a call from a collector inquiring about federal regulations who claimed to have a large box full of roots. Ladies slippers have also been collected for gardens, but the transplants commonly fail (Deborah White pers. comm.).

This species is protected in Georgia as a Special Concern Plant, a category that is used for commercially exploited species that are infrequent in the state and often dug for horticultural or medicinal purposes (Georgia Natural Heritage Program). The situation in Georgia is described as follows: "Permits are required to dig, sell or transport [this species]. There is little enforcement carried out with regard to protected plants. Yellow ladyslippers are sold by half a dozen individuals who propagate the species by rhizome division mostly from plants on their own lands. There are some illegitimate nurseries still obtaining plants dug from the wild without permit or landowner permission. The yellow ladyslippers when sold by permit are required to have transport tags, a copy of which is filed with the Georgia Natural Heritage Program. During 1993 through 1999, records indicate that as few as zero individuals to as many as 43 individuals per year were sold by permit (as garden plants) in Georgia. There is no estimate on numbers taken without permit, nor do we have any misdemeanors filed against individuals for removing yellow ladyslippers within the past few years." (Tom Patrick pers. comm.)

Plants are probably collected in the southern part of the range of the species in Manitoba (Elizabeth Punter pers. comm.).

An individual knowledgable about the medicinal herb trade states that Cypripedium is insignificant in the market currently and estimates trade on the order of ten pounds of dry root per year (McGuffin pers. comm.). It may be that horticultural collection is a much greater threat than medicinal usage, but this requires further research.

Any serious efforts to collect this plant for the plant trade could have negative impacts on this species in Indiana, where it is not common (Mike Homoya pers. comm.). In Missouri, wild-collection for personal gardens threatens populations (Tim Smith pers. comm.).

All Cypripedium species are listed by the United Plant Savers At Risk Forum on their "At Risk" list. This list consists of "herbs which are broadly used in commerce and which, due to over-harvest, loss of habitat, or by the nature of their innate rareness or sensitivity are either at risk or have significantly declined in numbers within their current range" (United Plant Savers 2000).

Other than threats from plant collection and habitat loss, like many orchids, Cypripedium parviflorum var. pubescens may be relatively intolerant of degraded natural habitat (Swink and Wilhelm 1994), and to the extent that this is so, it is relegated to a decreasing portion of the natural landscape, which is threatened by pollution, changes in hydrology, resource harvesting, over-abundance of certain animals (such as deer), alien species invasion, and loss of landscape connectivity.

Other than collection, the following threats are reported from across the plant's range. Illinois: competitive exclusion by exotic species such as bush honeysuckle and garlic mustard (Bill McClain pers. comm.); Wyoming: grazing by livestock in the Bighorn Range, vulnerability to trampling by off-road vehicles and hikers (Walt Fertig pers. comm.); Idaho: weed invasion and right-of-way maintenance (Michael Mancuso pers. comm.); Mississippi: widespread land conversion, such as land clearing and the establishment of pine plantations (Ronald Wieland pers. comm.); New Mexico: individuals in one occurrence found with tops clipped off, not clear if due to grazing or collection (Sara Gottlieb pers. comm.); Georgia: rooting by wild pigs (Tom Patrick pers. comm.); Manitoba: road maintenance (herbiciding, mowing, ditch cleaning, removal of woody vegetation), forestry activities, agricultural activities (haying, grazing, tillage), and picking and digging of plants (Elizabeth Punter pers. comm.).

Biological Research Needs: Efforts should be made to determine the volume of plant material that is currently being traded or explanted. This could provide an indirect indication of the impact of the plant trade and of hobby gardening by orchid enthusiasts on this species. It is also necessary to determine the threats posed by collection for the medicinal trade versus the horticultural trade or personal collection for gardens.

The confusion over the nomenclature, taxonomy, range, and habitats of Cypripedium parviflorum var. pubescens needs to be resolved before a solid conservation assessment can be developed. Also, research into its sensitivity to deer over-browse, and its ability to recolonize areas of forest regrowth or once-disturbed soils would shed much light onto its longer-term prospects.

The preference is partial sun to light shade, moist to slightly dry conditions, and a soil that consists of loam or sandy loam. Young plants require the presence of the appropriate endomycorrhizal fungus in the soil in order to flourish. Starting plants from seed is the job of an expert, although it is possible to successfully transplant large plants that have been grown in a greenhouse. This is one of the easier orchids to maintain in a flower garden.

Comments: Species in this same genus, Cypripedium, have been used medicinally by both Native and Euro-Americans (Niering 1979, Weiner 1980).

The roots of Cypripedium parviflorum were used by the Cherokee as a treatment for worms, and the roots of all Cypripedium species were used as a treatment for insomnia, nervousness, or nerve-related disorders by Native Americans and Euro-Americans (Niering 1979, Weiner 1980). References describing medicinal uses cannot be associated with single species or varieties with great confidence, as the species/variety and nomenclature for Cypripedium parviflorum var. pubescens and related strains (complex) is confusing and perhaps not yet standardized; although, references do imply that the medicinal uses were not restricted to one species or variety of Cypripedium.

Herbalists in the U.S. have agreed not to purchase, dig, or use any Cypripedium species in their formulas [however, not all companies are complying with this agreement, and wild-collection continues]. In the late 1800s, Cypripedium was very popular as a nervine tonic (Robyn Klein pers. comm.). Cypripedium pubescens is listed as an ingredient in a recipe for making a homeopathic remedy for poison ivy and poison oak on internet websites (Frontier Co-op 2000). As a medicinal herb, the rhizomes are used to make a tincture. Two more common species, Scutellaria lateriflora and Lavendula angustifolia, are recommended as suitable substitutes for Cypripedium for medicinal uses (Ed Fletcher pers. comm.).

Prices for this species were found as follows:

Georgia: $6.00/single root or rhizome (Tom Patrick pers. comm.)

Toronto, Canada: $24.95/individual plant, $68.00/3 plants (Elizabeth Punter pers. comm.)

Comments: The varietal-level taxon Cypripedium parviflorum var. pubescens of Kartesz (1999) corresponds to the species C. pubescens of Kartesz (1994) where C. pubescens was recognized at the species rather than the varietal level.