Cypripedium candidum - Muhl. ex Willd.
Small White Lady's-slipper
Other Common Names: white lady's slipper
Taxonomic Status: Accepted
Related ITIS Name(s): Cypripedium candidum Muhl. ex Willd. (TSN 43542)
French Common Names: cypripède blanc
Unique Identifier: ELEMENT_GLOBAL.2.157660
Element Code: PMORC0Q050
Informal Taxonomy: Plants, Vascular - Flowering Plants - Orchid Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Monocotyledoneae Orchidales Orchidaceae Cypripedium
Check this box to expand all report sections:
Concept Reference
Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Cypripedium candidum
Taxonomic Comments: Distinct species.
Conservation Status

NatureServe Status

Global Status: G4
Global Status Last Reviewed: 22Jun1990
Global Status Last Changed: 22Jun1990
Rounded Global Status: G4 - Apparently Secure
Reasons: Although Cypripedium candidum's range has decreased rapidly in the last century, there are still numerous extant occurrences. Also, the protected occurrences extend across its range, thus potentially maintaining some degree of genetic diversity.
Nation: United States
National Status: N4
Nation: Canada
National Status: N1 (29Aug2016)

U.S. & Canada State/Province Status
United States Alabama (S1), Illinois (S2), Indiana (S2), Iowa (S3), Kentucky (S1), Maryland (S1), Michigan (S2), Minnesota (S3), Missouri (S1), Nebraska (S1), New Jersey (S1), New York (S1), North Dakota (S2S3), Ohio (S1), Pennsylvania (SX), South Dakota (S1), Virginia (S1), Wisconsin (S3)
Canada Manitoba (S2), Ontario (S1), Saskatchewan (SH)

Other Statuses

Canadian Species at Risk Act (SARA) Schedule 1/Annexe 1 Status: E (05Jun2003)
Committee on the Status of Endangered Wildlife in Canada (COSEWIC): Threatened (28Nov2014)
Comments on COSEWIC: Designated Endangered in April 1981. Status re-examined and confirmed in April 1999 and in May 2000. Status re-examined and designated Threatened in November 2014.

NatureServe Global Conservation Status Factors

Range Extent Comments: Extant in seventeen states and two Canadian provinces. Manitoba south to central Nebraska, Iowa; east to Alabama, Kentucky, Maryland, New York and Ontario. Also in North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, Connecticut, New Jersey, Ohio, Indiana, Illinois. Extirpated from Pennsylvania and possibly Saskatchewan.

Number of Occurrences: 81 to >300
Number of Occurrences Comments: Minnesota: Over a hundred occurrences. The number of occurrences has declined 52% from historic county records (Natural Areas J. 3(4):19).

Population Size Comments: Most abundant in Minnesota and less common elsewhere.

Overall Threat Impact Comments: Encroachment by woody plants and successional change, habitat destruction, collection by wildflower hunters, herbicide application, loss of pollinators.

Short-term Trend: Relatively Stable (<=10% change)

Intrinsic Vulnerability Comments: Shade-intolerant, maintainence of healthy, viable EOs requires active management.

Other NatureServe Conservation Status Information

Global Range: Extant in seventeen states and two Canadian provinces. Manitoba south to central Nebraska, Iowa; east to Alabama, Kentucky, Maryland, New York and Ontario. Also in North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, Connecticut, New Jersey, Ohio, Indiana, Illinois. Extirpated from Pennsylvania and possibly Saskatchewan.

U.S. States and Canadian Provinces
Color legend for Distribution Map

U.S. & Canada State/Province Distribution
United States AL, IA, IL, IN, KY, MD, MI, MN, MO, ND, NE, NJ, NY, OH, PAextirpated, SD, VA, WI
Canada MB, ON, SK

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
AL Colbert (01033), Dallas (01047)
IA Adair (19001)*, Allamakee (19005), Benton (19011)*, Black Hawk (19013)*, Boone (19015)*, Bremer (19017), Buchanan (19019), Buena Vista (19021)*, Cerro Gordo (19033), Cherokee (19035), Chickasaw (19037), Clay (19041), Clayton (19043), Clinton (19045)*, Crawford (19047), Decatur (19053), Dickinson (19059), Emmet (19063), Fayette (19065), Floyd (19067), Franklin (19069)*, Grundy (19075)*, Guthrie (19077), Hamilton (19079), Hardin (19083)*, Howard (19089), Iowa (19095)*, Jasper (19099)*, Jones (19105), Kossuth (19109), Linn (19113)*, Marshall (19127)*, Mitchell (19131), Monona (19133), Montgomery (19137), Muscatine (19139)*, O Brien (19141), Palo Alto (19147), Polk (19153), Poweshiek (19157)*, Sac (19161)*, Scott (19163)*, Story (19169)*, Tama (19171)*, Webster (19187)*, Winnebagao (19189), Winneshiek (19191)*, Worth (19195), Wright (19197)
IL Cass (17017), Cook (17031), DuPage (17043), Kane (17089), Lake (17097), Mason (17125)*, Mchenry (17111), Will (17197), Winnebago (17201)
IN Fountain (18045), Fulton (18049)*, Henry (18065), Kosciusko (18085), La Porte (18091), Lagrange (18087), Lake (18089), Marshall (18099), Noble (18113), Porter (18127), Randolph (18135)*, St. Joseph (18141), Steuben (18151), Tippecanoe (18157), Wabash (18169)
KY Hardin (21093), Lewis (21135)
MD Washington (24043)
MI Allegan (26005), Barry (26015)*, Berrien (26021), Branch (26023)*, Calhoun (26025), Cass (26027), Clinton (26037)*, Genesee (26049), Hillsdale (26059), Huron (26063), Ingham (26065), Ionia (26067)*, Jackson (26075), Kalamazoo (26077), Kent (26081), Lenawee (26091), Livingston (26093), Oakland (26125), St. Clair (26147), St. Joseph (26149), Tuscola (26157), Van Buren (26159), Washtenaw (26161)
MN Anoka (27003)*, Becker (27005), Big Stone (27011), Blue Earth (27013), Brown (27015), Carver (27019), Chippewa (27023), Clay (27027), Cottonwood (27033), Dakota (27037), Dodge (27039), Douglas (27041), Faribault (27043), Fillmore (27045), Freeborn (27047), Goodhue (27049)*, Grant (27051), Hennepin (27053)*, Houston (27055), Jackson (27063), Kandiyohi (27067), Kittson (27069), Lac Qui Parle (27073), Le Sueur (27079), Lincoln (27081), Lyon (27083), Mahnomen (27087), Marshall (27089), Martin (27091), Mcleod (27085), Meeker (27093), Mower (27099), Murray (27101), Nicollet (27103), Nobles (27105), Norman (27107), Otter Tail (27111), Pennington (27113), Pipestone (27117), Polk (27119), Pope (27121), Ramsey (27123)*, Red Lake (27125), Redwood (27127), Renville (27129), Rice (27131)*, Rock (27133), Scott (27139), Stearns (27145), Steele (27147), Stevens (27149), Swift (27151), Waseca (27161), Washington (27163)*, Watonwan (27165)*, Wilkin (27167), Winona (27169), Yellow Medicine (27173)
MO Andrew (29003)*, Atchison (29005)*, Buchanan (29021)*, Carter (29035)*, Dallas (29059), DeKalb (29063)*, Dent (29065)*, Franklin (29071)*, Gentry (29075), Holt (29087)*, Howell (29091), Jefferson (29099)*, Nodaway (29147)*, Oregon (29149)*, Reynolds (29179)*, Shannon (29203), St. Charles (29183)*, St. Louis (29189)*, St. Louis (city) (29510)*, Texas (29215)*
ND Benson (38005), Cass (38017), Eddy (38027), Foster (38031)*, Grand Forks (38035), Griggs (38039), Nelson (38063), Ransom (38073), Richland (38077), Rolette (38079), Sargent (38081)*, Walsh (38099)
NE Brown (31017), Buffalo (31019)*, Butler (31023)*, Cherry (31031), Colfax (31037)*, Custer (31041), Dodge (31053)*, Douglas (31055)*, Greeley (31077)*, Hamilton (31081)*, Holt (31089), Howard (31093), Kearney (31099)*, Keya Paha (31103), Lancaster (31109)*, Merrick (31121)*, Pierce (31139), Platte (31141), Rock (31149), Saunders (31155)*, Sherman (31163), Valley (31175), Washington (31177)*
NJ Warren (34041)*
NY Erie (36029)*, Genesee (36037), Livingston (36051), Onondaga (36067)*
OH Adams (39001), Erie (39043), Portage (39133), Sandusky (39143), Seneca (39147)
PA Beaver (42007)*, Lancaster (42071)*, Venango (42121)*
SD Brookings (46011), Clay (46027)*, Deuel (46039), Minnehaha (46099)*, Roberts (46109), Union (46127)*
VA Montgomery (51121)
WI Buffalo (55011)*, Calumet (55015)*, Columbia (55021), Crawford (55023)*, Dane (55025), Dodge (55027), Fond Du Lac (55039), Grant (55043)*, Green (55045)*, Green Lake (55047), Iowa (55049), Jefferson (55055), Kenosha (55059), Marquette (55077), Milwaukee (55079)*, Outagamie (55087)*, Racine (55101)*, Richland (55103)*, Rock (55105), Sauk (55111)*, Trempealeau (55121)*, Walworth (55127), Waukesha (55133), Winnebago (55139)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
02 Middle Delaware-Musconetcong (02040105)+*, Lower Susquehanna (02050306)+*, Conococheague-Opequon (02070004)+
03 Upper Roanoke (03010101)+, Middle Alabama (03150203)+
04 Upper Fox (04030201)+, Wolf (04030202)+, Lake Winnebago (04030203)+*, Lower Fox (04030204)+*, Little Calumet-Galien (04040001)+, Pike-Root (04040002)+, Milwaukee (04040003)+*, St. Joseph (04050001)+, Kalamazoo (04050003)+, Upper Grand (04050004)+, Maple (04050005)+*, Lower Grand (04050006)+, Pigeon-Wiscoggin (04080103)+, Shiawassee (04080203)+, Flint (04080204)+, Lake St. Clair (04090002)+, Clinton (04090003)+, Detroit (04090004)+*, Huron (04090005)+, Raisin (04100002)+, St. Joseph (04100003)+, Blanchard (04100008)+, Sandusky (04100011)+, Cuyahoga (04110002)+, Upper Genesee (04130002)+, Lower Genesee (04130003)+, Seneca (04140201)+*, Oneida (04140202)+*
05 Middle Allegheny-Tionesta (05010003)+*, Upper Ohio (05030101)+*, Ohio Brush-Whiteoak (05090201)+, Eel (05120104)+, Tippecanoe (05120106)+, Middle Wabash-Little Vermilion (05120108)+, Upper White (05120201)+, Rolling Fork (05140103)+
06 Pickwick Lake (06030005)+
07 Sauk (07010202)+, Crow (07010204)+, South Fork Crow (07010205)+, Twin Cities (07010206)+*, Upper Minnesota (07020001)+, Pomme De Terre (07020002)+, Lac Qui Parle (07020003)+, Hawk-Yellow Medicine (07020004)+, Chippewa (07020005)+, Redwood (07020006)+*, Middle Minnesota (07020007)+, Cottonwood (07020008)+, Blue Earth (07020009)+, Watonwan (07020010)+, Le Sueur (07020011)+, Lower Minnesota (07020012)+, Lower St. Croix (07030005)+*, Rush-Vermillion (07040001)+*, Cannon (07040002)+, Buffalo-Whitewater (07040003)+*, Trempealeau (07040005)+*, La Crosse-Pine (07040006)+, Root (07040008)+, Coon-Yellow (07060001)+, Upper Iowa (07060002)+, Turkey (07060004)+, Maquoketa (07060006)+, Castle Rock (07070003)+*, Baraboo (07070004)+, Lower Wisconsin (07070005)+, Kickapoo (07070006)+*, Copperas-Duck (07080101)+*, Upper Wapsipinicon (07080102)+, Lower Wapsipinicon (07080103)+*, South Skunk (07080105)+, North Skunk (07080106)+*, Upper Cedar (07080201)+, Shell Rock (07080202)+, Winnebago (07080203)+, West Fork Cedar (07080204)+, Middle Cedar (07080205)+, Lower Cedar (07080206)+*, Upper Iowa (07080207)+, Middle Iowa (07080208)+*, Lower Iowa (07080209)+*, Upper Rock (07090001)+, Crawfish (07090002)+, Pecatonica (07090003)+, Sugar (07090004)+, Lower Rock (07090005)+, Kishwaukee (07090006)+, Des Moines Headwaters (07100001)+, Upper Des Moines (07100002)+, East Fork Des Moines (07100003)+, Middle Des Moines (07100004)+, Boone (07100005)+, North Raccoon (07100006)+*, South Raccoon (07100007)+, Lake Red Rock (07100008)+, Peruque-Piasa (07110009)+*, Kankakee (07120001)+, Chicago (07120003)+, Des Plaines (07120004)+, Upper Fox (07120006)+, Lower Fox (07120007)+, Lower Sangamon (07130008)+, Cahokia-Joachim (07140101)+*, Meramec (07140102)+*
09 Willow (09010004)+, Bois De Sioux (09020101)+, Mustinka (09020102)+, Otter Tail (09020103)+, Upper Red (09020104)+, Western Wild Rice (09020105)+, Buffalo (09020106)+, Elm-Marsh (09020107)+, Eastern Wild Rice (09020108)+, Upper Sheyenne (09020202)+, Middle Sheyenne (09020203)+, Lower Sheyenne (09020204)+, Maple (09020205)+, Sandhill-Wilson (09020301)+, Red Lake (09020303)+, Clearwater (09020305)+, Grand Marais-Red (09020306)+, Turtle (09020307)+, Forest (09020308)+, Snake (09020309)+, Park (09020310)+, Lower Red (09020311)+, Two Rivers (09020312)+
10 Middle Niobrara (10150004)+, Keya Paha (10150006)+, Lewis and Clark Lake (10170101)+*, Vermillion (10170102)+*, Middle Big Sioux Coteau (10170201)+, Upper Big Sioux (10170202)+, Lower Big Sioux (10170203)+, Rock (10170204)+, Middle Platte-Buffalo (10200101)+*, Wood (10200102)+*, Middle Platte-Prairie (10200103)+*, Lower Platte-Shell (10200201)+, Lower Platte (10200202)+*, Salt (10200203)+*, Lower Middle Loup (10210003)+, South Loup (10210004)+*, Lower North Loup (10210007)+, Loup (10210009)+, Upper Elkhorn (10220001)+, North Fork Elkhorn (10220002)+, Lower Elkhorn (10220003)+*, Little Sioux (10230003)+, Monona-Harrison Ditch (10230004)+, Boyer (10230007)+, Keg-Weeping Water (10240001)+*, Nishnabotna (10240004)+*, Tarkio-Wolf (10240005)+, West Nodaway (10240009)+*, Nodaway (10240010)+*, Independence-Sugar (10240011)+*, Platte (10240012)+*, One Hundred and Two (10240013)+*, Upper Big Blue (10270201)+*, Upper Little Blue (10270206)+*, Upper Grand (10280101)+, Thompson (10280102)+, Niangua (10290110)+, Lower Missouri (10300200)+*
11 Upper Black (11010007)+*, Current (11010008)+, Eleven Point (11010011)+*
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
General Description: A perennial orchid with a white, pouch-shaped flower ('slipper') that is streaked with a rose-purple colour. In Manitoba, this species blooms from late May through mid-June and seeds are released from capsules in early September.
Technical Description: Plants erect, 11-40 cm. Leaves 3-4(-5), on proximal or middle portion of stem, alternate, erect-ascending; blade lanceolate or elliptic to oblanceolate, 7-20 × 0.9-5.3 cm. Flowers 1(-2); sepals green to pale brownish yellow, usually spotted and striped with reddish brown or madder; dorsal sepal ovate to ovate-lance-acuminate, 15-35 × 7-13 mm; lateral sepals connate; synsepal 13-35 × 7-15 mm; petals spreading to somewhat deflexed, same color as sepals, spirally twisted or spiral-undulate, lanceolate to linear-lanceolate, 23-46 × 3-5 mm; lip white, obovoid or oblance-ovoid to oblance-fusiform, 17-27 mm; orifice basal, 10-15 mm; staminode lanceoloid or oblong-lanceoloid to ellipsoid. 2n = 20..
Diagnostic Characteristics: Small White Lady's-slippers can hybridize with Yellow Lady's-slippers (Cypripedium parviflorum). The flowers of the hybrids are usually light yellow or cream-coloured, not pure white. Hybrid plants also tend to be larger than Small White Lady's-slippers.

Duration: PERENNIAL, Long-lived
Palustrine Habitat(s): Bog/fen
Terrestrial Habitat(s): Grassland/herbaceous
Habitat Comments: Mesic blacksoil prairie, wet blacksoil prairie, glacial till hill prairie, sedge meadow, calcareous fen, glade. Calcareous soils. In Manitoba, this species can be found in moist calcareous (calcium-rich, or alkaline) prairie areas or openings in wooded grasslands. It most often grows in relatively undisturbed grassland, but can also be found in moderately disturbed sites such as roadside ditches.

Economic Attributes
Economically Important Genus: Y
Management Summary
Stewardship Overview: Prescribed burning of all habitat types; maintenance of adequate groundwater levels; maintenance of pollinator breeding habitat; control of livestock and other habitat degraders.
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 06May1990
NatureServe Conservation Status Factors Author: Ostlie, W. (MRO)( M. Ormes 1986), ed. G. Davis (Oct. 2012)
Management Information Edition Date: 21Mar1986
Management Information Edition Author: JOYCE BENDER
Element Ecology & Life History Edition Date: 21Oct2009
Element Ecology & Life History Author(s): C. Friesen

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

  • Anderson, A. 1993. Micropropogation of the Small White Ladies Slipper from Turkey Point. Interim Report. Ontario Ministry of Natural Resources, Simcoe District.

  • Anderson, A.B. 1990. Improved germination and growth of rare native Ontario orchid species. Pages 65-73 in "Conserving Carolinian Canada: Conservation Biology in the Deciduous Forest Region", edited by G.M. Allen, P.F.J. Eagles, and S.D. Price. University of Waterloo Press, Waterloo, Ontario..

  • Argus, G.W., K.M. Pryer, D.J. White and C.J. Keddy (eds.). 1982-1987. Atlas of the Rare Vascular Plants of Ontario.. Botany Division, National Museum of National Sciences, Ottawa.

  • Bender, J. 1985. Organismal interdependence and species survival in Cypripedium candidum Mhul. ex Willd. (Orchidaceae). Unpublished M.S. thesis, University of Akron, Ohio.

  • Biondini, M.E. and L. Manske. 1996. Grazing frequency and ecosystem processes in a northern mixed prairie, USA. Ecological Applications 6(1): 239-256.

  • Boe, J., Puchalski, L, Jacobson, B., and M. Schreiber. 2002. Information on transplanting Lady's-slipper orchids and other plants protected by the Minnesota Wildflower Act. Double-sided handout.

  • Bowles, M.L. 1983. The tallgrass prairie orchids PLATANTHERA LEUCOPHAEA (Nutt.) Lindl. and CYPRIPEDIUM CANDIDUM Muhl. ex Willd.: some aspecits of their status, biology, and ecology, and implications towards manangement. Natural Areas Journal 3(4):14-37.

  • Brdar, Corina. 2005. Challenges to protecting species at risk in provincial parks and protected areas in Ontario. Protected Areas and Species and Ecosystems at Risk: Research and Planning Challenges. Nelson, Gordon et al. Eds. pp. 45-52.

  • Brownell, V.R. 1981. Status Report on the Small White Lady's Slipper, CYPRIPEDIUM CANDIDUM, in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Ottawa, Ontario. 57 pp.

  • Brownell, V.R. 1984. An inventory and assessment of the Small White Lady's-slipper and its hybrids at Turkey Point Provincial Park. Ontario Ministry of Natural Resources, Simcoe, Ontario. 34 pp.

  • Brownell, V.R. 1997. Update Status Report on Small White Lady's-slipper (CYPRIPEDIUM CANDIDUM Muhl. ex Willd.) in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Ottawa, Ontario. 12 pp.

  • Carroll, S., R.L. Miller and P.D. Whitson. 1984. Status of four orchid species at Silver Lake Fen complex. Proc. Iowa Acad. Sci. 91:132-139.

  • Case, M. 1994. Extensive variation in the levels of genetic diversity and degree of relatedness among five species of Cypripedium (Orchidaceae). American Journal of Botany 81:175-184.

  • Catling, P. M., and G. Knerer. 1980. Pollination of the small white lady's-slipper (Cypripedium candidum) in Lambton County, southern Ontario. Canadian Field-Naturalist 94:435-38.

  • Catling, P.M. and G. Knerer. 1980. Pollination of the small white lady's slipper (Cypripedium candidum) in Lambton County, Southern Ontario. Canadian Field-Naturalist 94(4):435-438.

  • Catling, P.M., and G. Knerer. 1980. Pollination of the small white lady's-slipper (Cypripedium candidum) in Lambton County, southern Ontario. Canadian Field-Naturalist. 94(4):435-438.

  • Coffin, B., and L. Pfannmuller, editors. 1988. Minnesota's endangered flora and fauna. University of Minnesota Press, Minneapolis, Minnesota. 473 pp.

  • Coffin, B., and L. Pfannmuller, editors. 1988. Minnesota's endangered flora and fauna. University of Minnesota Press, Minneapolis. 473 pp.

  • Curtis, J. T. 1943. Germination and seedling development in five species of Cypripedium. American Journal of Botany 30:199-206.

  • Curtis, J.T. 1932. A new Cypripedium hybrid. Rhodora 34: 239-242.

  • Curtis, J.T. 1946. Use of mowing in management of White Ladyslipper. Journal of Wildlife Management 10(4):303-308.

  • Curtis, J.T. 1954. Annual Fluctuation in Rate of Flower Production by Native Cypripediums During Two Decades. Bulletin of the Torrey Botanical Club 81 (4): 340-352. A54CUR01PAUS.

  • Environment Canada. 2006. Recovery Strategy for Small White Lady's-slipper (Cypripedium candidum) in Canada. In Species at Risk Act Recovery Strategy Series. Ottawa: Environment Canada. 23 pp.

  • Falb, D.L., and D.J. Leopold. 1993. Population dynamics of Cypripedium candidum Muhl. ex Willd., Small White Ladyslipper, in a western New York fen. Natural Areas Journal 13(2): 76-86.

  • Fernald, M. L. 1950. Gray's manual of botany. Eighth edition. A handbook of the flowering plants and ferns of the central and northeastern United States and Adjacent Canada. American Book Co., New York.

  • Flora of North America Editorial Committee. 2002a. Flora of North America North of Mexico. Vol. 26. Magnoliophyta: Liliidae: Liliales and Orchidales. Oxford Univ. Press, New York. xxvi + 723 pp.

  • From, M. M. 2007. Drought, Peril, and Survival in the Great Plains: Cypripedium candidum. North American Native Orchid Journal 13(2): 66-74.

  • Fuller, A.M. 1932. A natural Cypripedium hybrid from Wisconsin. Rhodora 34(402):97-101.

  • Garay, L.A. 1953. A new natural hybrid Cypripedium from Ontario. Canadian Journal of Botany 31: 660-662.

  • Geomatics International Inc. 1995. Habitat restoration plan for the Turkey Point Wilderness Area with a focus on the Small White Lady's-slipper. Ontario Ministry of Natural Resources, Simcoe District, Simcoe. 39 pp.

  • Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.

  • Harkin, R. J., and P. D. Ascher. 1981-1982. North temperate terrestrial orchid habitat study and seed pod collection of Plantanthera leucophaea, Cypripedium candidum, and Goodyera pubescens. University of Minnesota, Department of Horticulture and Landscape Architecture, St. Paul. 17 pp.

  • Hohn, S. 1994. An update on Small White lady's-slipper in the Brandon area. Critical Wildlife habitat program. Manitoba Ministry of Natural Resources, Winnepeg. 4 pp.

  • Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.

  • Imrie, Anita et al. 2005. Small white lady's-slipper: impacts of fen succession. Protected areas and species and ecosystems at risk: research and planning challenges. Nelson, Gordon et al., Eds. pp. 127-135.

  • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

  • Kirk, D. 1990. Summary of historical and current information of the Small White Lady Slipper (CYPRIPEDIUM CANDIDUM) and hybrids at Turkey Point, Ontario and recommendations for species and habitat management. Unpublished report, Ontario Ministry of Natural Resources, Simcoe. 38 pp.

  • Klier, K., Leoschke, M.J., and J.F. Wendel. 1991. Hybridization and introgression in white and yellow ladyslipper orchids (Cypripedium candidum and Cypripedium pubescens). Journal of Heredity. 82(4):305-318.

  • Line, J. and M.J. Oldham. 1999. COSSARO Candidate V, T, E Species Evaluation Form - Small White Lady's-slipper (Cypripedium candidum). Committee on the Status of Species at Risk in Ontario (COSSARO), Ontatrio Ministry of Natural Resources. 3 pp.

  • Marshell, H.H., Gross A.T., and Stevenson, G.A. 1966. Natural hybrids of lady's slippers (Cypripedium) in Manitoba. Rhodora 68:53-58.

  • Niemann, D. 1986. The distribution of orchids in Iowa. Proceedings of the Iowa Academy of Science 93(1):24-34.

  • Oldham, M.J. 1997. COSSARO Candidate V,T,E Species Evaluation Form for Small White Lady's-slipper (Cypripedium candidum). Unpublished report prepared by Natural Heritage Information Centre for Committee on the Status of Species at Risk in Ontario (COSSARO), Ontario Ministry of Natural Resources. 4 pp.

  • Oldham, M.J. 1998. COSSARO Candidate V,T,E Species Evaluation Form for Small White Lady's-slipper (Cypripedium candidum). Unpublished report prepared by Natural Heritage Information Centre for Committee on the Status of Species at Risk in Ontario (COSSARO), Ontario Ministry of Natural Resources. 4 pp.

  • Ostlie, W. 1990. Element Stewardship Abstract for CYPRIPEDIUM CANDIDUM - Small White Lady's slipper. The Nature Conservancy, Midwest Regional Office, Minneapolis, Minnesota. [27 unnumbered pages].

  • Punter, Elizabeth. Recovery Watch, Manitoba Conservation Data Centre.

  • Saunders, W.E. 1926. Cypripedium candidum. Canadian Field-Naturalist 40(2):112-113.

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