Description: Small White Lady’s-Slipper is a perennial orchid growing 20 to 36 centimetres tall in clumps of up to 60 stems from a short rhizome. The two to four pleated leaves are seven to 15 centimetres long by two to four centimetres wide and appear firm and upright, crowded about the middle of the stem. The bases of the leaves overlap and the lower portion of the stem has several prominent sheaths. The one to two flowers have large leaf-like bracts 3.5 to six centimetres long and up to two centimetres wide. The pouch of the white slipper-shaped flower can be up to 2.5 centimetres long and the inside has purple veins. The other flower parts are greenish-yellow, usually with purple streaks, strap-shaped and twisted, growing from behind the base of the pouch. The outer three are about 2.5 centimetres long and one centimetre wide while the inner two are narrower and more twisted, 2.5 to four centimetres long and only three to six millimetres wide. The flowers are somewhat fragrant and are not stalked above the bract.

Similar species: Yellow Lady’s-Slippers (Cypripedium parviflorum varieties parviflorum and pubescens) differ from Small White Lady’s-Slipper in flower color and size. The leaves are somewhat arched from the stem five to 21 centimetres long by two to 11 cemtimetres wide, and also pleated but they are covered with tiny glandular hairs. The flowers are on stalks to one centimetres long or more. The outer flower parts are yellowish, greenish or reddish or greenish-brown, only weakly twisted 2.5 to eight centimetres long by one to two centimetres wide; the lower one beginning at the sides and two to 7.5 centimetres long by 0.6 to 1.8 centimetres wide. The inner two are twisted and three to nine centimetres long by one centimetre wide and have long hairs near their bases. Spots of purple or purple veins occasionally appear on the inside of the pouch which may be 1.8 to five centimetres long.

Status: The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) listed Small White Lady’s-Slipper as endangered in 1981. Currently, Small White Lady’s-Slipper is protected under the Convention on International Trade in Endangered Species (CITES) of Wild Fauna and Flora as well as the Saskatchewan, Ontario and Manitoba Endangered Species Acts.

Historically the plant was found in 15 states and three provinces. In 1980, Small White Lady’s Slipper was found in 11 states and two provinces. Today, populations are rapidly declining due to loss of habitat. The current Small White Lady’s-Slipper population is estimated to be only 33 per cent of its historic population.

In Canada, Small White Lady’s-Slipper previously occurred in Saskatchewan, Ontario and Manitoba. The plant is now believed to be extirpated from Saskatchewan. Currently, its range in Canada consists of only two sites in Ontario and four sites in southern Manitoba.

In the United States, Small White Lady’s-Slipper’s historic range consisted of Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, Nebraska, New Jersey, New York, North Dakota, Ohio, Pennsylvania, South Dakota and Wisconsin. Today, Minnesota has the largest population of Small White Lady’s-Slipper plants.

Range Map (Distribution of Small White Lady’s Slipper (Cypripedum candidum) adapted from Environment Canada. 2000 and Brownell. 1981)

Habitat: Small White Lady’s-Slipper was previously found in open tall-grass prairies, dry hillsides and prairies with calcium carbonate (calcareous) deposits. Agricultural practices and human development have reduced the range of the species. Today it is found in prairie openings, wooded grasslands, marshy areas and calcareous sandy loam soil with southern exposure. Small White Lady’s-Slipper is shade intolerant and therefore requires good sun exposure.

Life Cycle: Many stems can grow from one rhizome and each stem produces one or two flowers. In Manitoba, flowering begins around late May or early June. Small White Lady’s-Slipper takes approximately 13 years to flower.

The Orchid family is equipped with special devices to ensure cross-fertilization. Orchids rely on insects for pollination. Only a few types of insects (mainly bees) can fit into the flower structure. Once inside the orchid’s pouch, they can only exit in one direction. The pollen rubs onto the insects back while leaving the flower. This prevents the insect from self-pollinating the plant.

Each capsule contains a few thousand minute seeds which are usually shed by late July. Seed production can be reduced by cool temperatures. The seeds are resistant to wetting and have a dry storage of at least eight years.

Orchids have an obligatory relationship with a certain type of fungus. The attachment of the correct fungus to the root provides additional nutrients and water gathering capability. This extended root system is required for survival.

Limiting Factors and Recovery Needs: Loss of habitat is the major factor causing the decline of Small White Lady’s-Slippers. Most native tall-grass prairie has been broken for agriculture and urban development. Today, only fragments of land remain untouched.

Fire control is believed to contribute to the decline of the species since fire reduces vegetative competition. Small White Lady’s-Slipper is shade intolerant. Fire makes good seed bed conditions by releasing nutrients into the soil and opening up areas to more sunlight.

Many of the remaining populations of Small White Lady’s-Slipper grow on private land, making protection difficult. Lands protected by conservation groups are often visited by collectors seeking to add the flower to their collections. Picking the plant or taking the seeds reduces the possibility of them expanding the population through natural reproduction. Similarly, Small White Lady’s-Slipper should not be transplanted. They should be left in their natural habitat for the enjoyment of present and future generations.

The Small White Lady’s-Slipper needs protected habitat on suitable sites in order to make a recovery. Additional research is needed to fully understand the species needs and requirements.

Recovery Actions: Current recovery efforts are focused on studying native tall-grass prairie.

Research at the Tall-grass Prairie Preserve in Manitoba includes:

• The effects of grazing on Small White Lady’s Slipper: Research so far has indicated that populations doubled with rotational grazing.
• The effects of controlled burns: Prescribed burns control competitive woody vegetation. This allows Small White Lady’s-Slippers to receive the maximum amount of sunlight they require.

Recovery Actions in Ontario include:

• Two 10-hectare nursery sites have been established. The nurseries are made up of more than 50 species of grasses and flowers. In 1997, Small White Lady’s-Slippers were hand planted in remnant sites and plant development and seed production are being monitored.
• An Ontario Tallgrass Prairie Association has also been established to preserve the habitat and educate people on the importance of this threatened ecosystem.

Important: It is important to note that all endangered species including plants are protected under Provincial Endangered Species Acts. Endangered Species Acts make picking endangered plants and collecting the seeds of endangered plants unlawful.

In many cases, the entire ecosystem is endangered and not just a specific species. These ecosystems are fragile and should remain undisturbed. The continued survival of all endangered species relies on protecting the species at risk habitats as well as the species themselves. Field research is needed to fully assess what suitable habitat remains in Saskatchewan. This would help to determine the feasibility of possible re-introduction of this plant.

Selected References: Please contact your local library or visit the Internet sites below for more information on the Small White Lady’s-Slipper.

Brownell, Vivian R. 1981. The small white lady’s-slipper in Canada: A status report.

The Committee on the Status of Endangered Wildlife in Canada.

Environment Canada. 2000. All species at risk (Map). [Online]
     http://www.sis.ec.gc.ca/cgi.eas/endanew.exe
     Date visited: 10/07/00

Environment Canada. 1999. Small white lady’s-slipper. [Online]
     http://www.speciesatrisk.gc.ca/Species/English/SearchDetail.cfm?SpeciesID=193

Punter, Elizabeth. 1999. Recovery Watch: Small, white and fragile. (page 7). Canadian Wildlife Service.