Cypripedium candidum
Encyclopedia
Cypripedium candidum, also known as Small White Lady's Slipper or White Lady's Slipper, is a rare orchid of the Cypripedium
genus. It is found in wet prairies and fen
s, in rich, highly calcareous
soils, sedge meadow edges, calcareous roadside and railway ditches. Cypripedium candidum grows to a height of 10 to 40 cm, and blooms from early May to June. Its white pouch-like lip, sometimes dotted with maroon on the inside, is accented by tan, green or brown lateral sepals and petals. It has been known to hybridize with the small yellow ladyslipper, Cypripedium parviflorum var. makasin, resulting in the natural hybrid Cypripedium X andrewsii. The leaves and stems are slightly pubescent. The plants grow in (generally) long-lived clumps, with some clumps having up to 50 or more flowers.
Cypripedium candidum is found from Western New York, across southern Ontario
to North Dakota
, and south to New Jersey
and Missouri
. There are isolated populations of Cypripedium candidumin Connecticut
, Maryland
Manitoba
, and (formerly) Saskatchewan
.
Cypripedium candidum is considered rare across Canada
, endangered in Ontario, and protected under the Ontario Endangered Species Act. It is believed to be extirpated from Saskatchewan. It is threatened in the United States, extirpated from Pennsylvania, endangered in South Dakota and Wisconsin, threatened in Illinois, Kentucky, and Michigan, and rare in Missouri and North Dakota. It is listed in Canada as N2, or endangered. Globally, however, it is listed as G4 (apparently secure) because there are protected sites across its entire range. It is a perennial, with horizontal, wiry-rooted rhizomes growing a few centimeters below the surface of the soil, and hence resistant to most prairie fires. It is shade-intolerant and therefore requires substantial management for invasive and woody species.
Cypripedium candidum is uncommon because it has a low seed set caused by often unpollinated flowers, as well as that its habitat of wet prairies and fens have been greatly decreased through draining for agricultural purposes. In Ontario, this orchid has never been common due to limited occurrences of fens in Cypripedium candidums Southern-Ontario range. Habitat loss due to fragmentation through agriculture and development, suppression of fire, incursions by invasive species, especially reed canary grass (Phalaris arundinaceae), dogwood (cornus sp.), leafy spurge, St. John’s wort and buckthorn (rhamnus sp.), changes in hydrology, loss of pollinators and environmental challenges to the obligate mycorrhizae that support this species are all responsible for its decline. This ladyslipper is most intolerant of shade, and so management of remnant prairies needs to be a part of any species recovery strategies. Long-term monitoring of this species is being done through various scientific organizations, including the Chicago Botanic Garden's respected Plants of Concern program.
Like many wild orchids, this species has been further endangered by collecting for generally futile attempts at cultivation. It is now known from only two sites in the province of Ontario.
Cypripedium
Cypripedium is a genus of 47 species of lady's-slipper orchids native to temperate and colder regions of the Northern Hemisphere.Some grow in the tundra in Alaska and Siberia, which is an unusually cold habitat for orchids. They can withstand extreme cold, growing under the snow and blooming when...
genus. It is found in wet prairies and fen
Fen
A fen is a type of wetland fed by mineral-rich surface water or groundwater. Fens are characterised by their water chemistry, which is neutral or alkaline, with relatively high dissolved mineral levels but few other plant nutrients...
s, in rich, highly calcareous
Calcareous
Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...
soils, sedge meadow edges, calcareous roadside and railway ditches. Cypripedium candidum grows to a height of 10 to 40 cm, and blooms from early May to June. Its white pouch-like lip, sometimes dotted with maroon on the inside, is accented by tan, green or brown lateral sepals and petals. It has been known to hybridize with the small yellow ladyslipper, Cypripedium parviflorum var. makasin, resulting in the natural hybrid Cypripedium X andrewsii. The leaves and stems are slightly pubescent. The plants grow in (generally) long-lived clumps, with some clumps having up to 50 or more flowers.
Cypripedium candidum is found from Western New York, across southern Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
to North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
, and south to New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
and Missouri
Missouri
Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...
. There are isolated populations of Cypripedium candidumin Connecticut
Connecticut
Connecticut is a state in the New England region of the northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, and the state of New York to the west and the south .Connecticut is named for the Connecticut River, the major U.S. river that approximately...
, Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
Manitoba
Manitoba
Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...
, and (formerly) Saskatchewan
Saskatchewan
Saskatchewan is a prairie province in Canada, which has an area of . Saskatchewan is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, and on the south by the U.S. states of Montana and North Dakota....
.
Cypripedium candidum is considered rare across Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, endangered in Ontario, and protected under the Ontario Endangered Species Act. It is believed to be extirpated from Saskatchewan. It is threatened in the United States, extirpated from Pennsylvania, endangered in South Dakota and Wisconsin, threatened in Illinois, Kentucky, and Michigan, and rare in Missouri and North Dakota. It is listed in Canada as N2, or endangered. Globally, however, it is listed as G4 (apparently secure) because there are protected sites across its entire range. It is a perennial, with horizontal, wiry-rooted rhizomes growing a few centimeters below the surface of the soil, and hence resistant to most prairie fires. It is shade-intolerant and therefore requires substantial management for invasive and woody species.
Cypripedium candidum is uncommon because it has a low seed set caused by often unpollinated flowers, as well as that its habitat of wet prairies and fens have been greatly decreased through draining for agricultural purposes. In Ontario, this orchid has never been common due to limited occurrences of fens in Cypripedium candidums Southern-Ontario range. Habitat loss due to fragmentation through agriculture and development, suppression of fire, incursions by invasive species, especially reed canary grass (Phalaris arundinaceae), dogwood (cornus sp.), leafy spurge, St. John’s wort and buckthorn (rhamnus sp.), changes in hydrology, loss of pollinators and environmental challenges to the obligate mycorrhizae that support this species are all responsible for its decline. This ladyslipper is most intolerant of shade, and so management of remnant prairies needs to be a part of any species recovery strategies. Long-term monitoring of this species is being done through various scientific organizations, including the Chicago Botanic Garden's respected Plants of Concern program.
Like many wild orchids, this species has been further endangered by collecting for generally futile attempts at cultivation. It is now known from only two sites in the province of Ontario.