1. Family: Orchidaceae Juss.
    1. Cypripedium L.

      1. This genus is accepted, and its native range is Temp. & Subalpine. Northern Hemisphere to Central America.

    [C-EM]
    Distribution

    A genus of about 47 species widespread in Europe, temperate Asia across to Japan and China and the Himalayas, Sakhalin, the Kurile and Aleutian Islands, North America, and south to Guatemala and Honduras. (PC).

    Ecology

    Our knowledge of the ecology of most hardy slipper orchids is still poor. This is particularly true of Asiatic and Mexican species, including those which are most narrowly endemic. The current vogues in many countries for habitat restoration and management and for reintroduction of rare species have emphasized the need for more information in order to provide optimal conditions for reintroduction. Detailed ecological observations and analyses are lacking for most species of Cypripedium, but the general ecological preferences of a number of species have been recorded. Most species grow in colonies. The colonies are small in some species, such as C. elegans, C. margaritaceum, and C. lichiangense, but can be extensive, covering hundreds of hectares, in species such as C. macranthos and C. tibeticum. Much depends on the extent of suitable habitat because most species seem to have rather specific edaphic, climatic, and shade requirements.

    Seasonality. All temperate slipper orchids are found in climates with a distinct seasonality, growing in the spring, flowering in early to mid-summer and setting seed in the autumn. They survive dormancy by storing food reserves in their fleshy rhizomes, and the dormant shoot lies with its tip at or just below the soil surface. Growth commences as the weather improves in early spring, influenced by increasing warmth and moisture. The majority of species flower in May, June, and early July. However, flowering can be as early as April in species such as C. kentuckiense and C. formosanum and as late as August in C. irapeanum and C. molle.

    A number of Asian species, such as C. guttatum, C. himalaicum, and C. tibeticum, are found most commonly in montane grassland and meadows. All grow at elevations of up to 4000 m or more, and the grassland is covered by deep snow in the winter and early spring. As the snow melts in May, C. tibeticum emerges among the brown grasses and flowers as its young leaves develop.


    Perner (personal communication) examined the distribution of C. macranthos, C. calceolus, and C. shanxiense in Primorsk in Siberia. He also noted that C. calceolus and C. shanxiense grow in slightly drier sites that C. macranthos. Cypripedium shanxiense grows in more shaded situations than C. calceolus.

    Substrate and pH. In Europe, C. calceolus is a well-known calcicole growing in. alkaline or rarely neutral soils. In England its former localities were on oolitic and magnesian limestone on north-facing slopes in light shade of oak and hazel woodland (Summerhayes 1968). However, Perner (personal communication) reports that he found it growing in slightly acidic conditions (pH 6) in eastern Siberia. In central Europe it grows in conifer forest and on the edges of mixed deciduous woods, often in flat or sloping sites, up to an elevation of 2000 m or more. In places it forms large colonies with individual plants bearing many shoots.

    Other plants often in the same habitat can comprise a single shoot, the propensity to produce clumps related to the branching of the rhizome.


    Many other Eurasian species are apparently calicoles, the extensive limestone regions of eastern Asia being host to many Cypripedium species. Species such as C. flavum, C. margaritaceum, C, lichiangense, C. forrestii, C. henryi and C. debile grow in mixed deciduous woods of poplar, birch, pine, fir, and larch. The substrate is hard limestone and the soils thin, comprising leaf litter and humus derived from the leaves of the forest trees with its understory dominated by rhododendrons. Such soils may not be alkaline; the author has measured a pH of around 5.5. The fact that the habitats often sustain a rich ericaceous flora confirms this. More work is needed to establish the effects of substrate on the ecology of Asiatic species. Perner (personal communication) measured the pH of soils where C. macanthos and C. shanxiense grow in eastern Siberia and found the soils ranged from neutral to slightly acidic (pH 6).


    The ecological preferences of the North American species have been catalogued by a number of authors (e.g. Morris and Eames 1929; Correll 1950; Luer 1975; Sheviak 1983; Griesbach and Asher 1983; Case 1987). Several species grow in acidic conditions, but Case makes the point that some of these grow in other habitats as well, for example C. acaule is recorded from acidic, mineral-poor Larix-Picea dominated bogs and other marshy habitats but also in pine-barrens on deep dry sands; C. parviflorum var. pubescens can grow in neutral or alkaline bogs; acidic, sterile, damp sandy soil with little vegetation; and in neutral to alkaline soils in deciduous woods and beach flats. Sheviak (1983) considered that soil chemistry is the most critical factor in the establishment of orchids because of its effect on the mycorrhizal fungi. The solubility of nutrients is particularly affected by pH, and levels of critical nutrients may allow a species to grow in both acidic and alkaline habitats but not in neutral ones where elements such as phosphorus, manganese, and boron are present in higher concentrations. Griesbach and Asher (1983) noted that C. reginae grows equally well in slightly acid (pH 6.3) or slightly alkaline soils (pH 7.8). 


    Rainfall and moisture. All temperate slipper orchids need adequate moisture during the growing season, but their tolerance of moisture in the substrate can vary substantially. Cypripedium acaule is recorded from both very wet habitats such as Sphagnum bogs and dry deep sands. Sharp drainage is a feature of most substrates that slipper orchids occupy. Adequate water supply during the growing season is essential, but too much moisture during dormancy may lead to shoot rot, as many growers have found to their cost.



    Succession. The effects of vegetational succession can be dramatic on temperate slipper orchid populations. Case (1987) reported that a thriving colony of C. reginae growing in a balsam fir-cedar bog declined dramatically when deer grazing was reduced. The deer heavily grazed the cedar, creating open lightly shaded or sunny glades in the forest where, in 1946, over 2000 plants flourished. By 1957 the reduction of the deer population by hunting had led to the regeneration of cedar and the shading of the glades. By 1960 most of the plants had disappeared or become spindly, almost like seedlings. Clearance of cedar by hand allowing more light into the forest resulted in the reappearance of flowering plants by 1962.



    It is not unusual to find areas where a few old clumps of C. calceolus, C. parviflorum var. pubescens or C. acaule survive in old woodland but with little or no sign of young seedlings. Conversely, in neighbouring areas where older trees have been cleared, seedlings may be common but large plants absent. Habitat management has been successful in restoring slipper orchid habitats to optimal level. In Europe there are several sites of C. calceolus in Germany and Switzerland that are carefully managed to maintain orchid populations at high levels. Clearance of heavily shaded areas improves light levels and provides bare soil where seed germination, and seedling growth is encouraged. In North America prairie management regimes have increased the populations of the rare C. candidum in several middle American states. (PC).

    General Description

    Terrestrial herbs. Roots elongate, fibrous, arising from a short to elongate rhizome; rhizomes present, short to elongate, creeping. Shoots erect, leafy, clustered or well spaced, terete, hairy, glandular or glabrous, the base enclosed by two to four sheathing sterile bracts, one- to several-leaved above; pseudo-bulbs absent. Leaves one-several, usually plicate, prostrate, spreading or suberect, lanceolate, ovate, elliptic, oblong or cordate, obtuse to acute or acuminate, green, spotted with blackish maroon in some species, glabrous or hairy, ciliate or not on the margins. Inflorescence terminal, one- to many-flowered; rachis terete, hairy, glandular or glabrous; bracts usually leaf-like but smaller than the uppermost leaf, rarely linear. Flowers usually showy, con-colorous or two-coloured; pedicel obscure to elongate, elongating after fertilization in some species; ovary unilocular, three-ribbed, glabrous, hairy or glandular. Dorsal sepal erect to hooded over lip, ovate, lanceolate or elliptic, obtuse, acute or acuminate, glabrous or pubescent on the outer surface, rarely pubescent within, ciliate or not; lateral sepals usually fused to form a concave synsepal that is similar to the dorsal sepal, but free and linear-lanceolate in section Criosanthes. Petals free, spreading, incurved or clasping the sides of the lip, elliptic, ovate, lanceolate, linear-lanceolate or sub-pandurate, rounded, obtuse, acute or acuminate, often pubescent in basal half within, usually ciliate. Lip deeply pouched and inflated, slipper-shaped or urn-shaped, glabrous or hairy on outer surface; side lobes incurved, entire, often much reduced; midlobe deeply saccate, incurved or not on front margin, hairy within especially on lower surface. Column porrect, short, stalked; anthers two, bilocular, borne on short obtuse to acute filaments; pollen powdery or viscid; staminode terminal on column, sessile or stalked, oblong, ovate, cordate or linear, flat, convex or conduplicate, glabrous to papillose or finely pubescent, ciliate or not; stigma stalked, dependent, tripartite, more or less papillose. Capsule erect to pendent, three-ribbed, cylindrical to almost ellipsoidal. (PC).

    Habitat

    Temperate slipper orchids are found over an extensive latitudinal range, extending from north of the Arctic Circle (about 70° North) in Alaska to 25° North in south-west China and even farther south (about 14° North) in Central America. In the northern part of their distribution slipper orchids are found from sea level into the lower hills, occupying coniferous forests, mixed deciduous woodlands, bogs, fens, grasslands or prairies. Farther south they usually inhabit montane woodlands and grasslands at higher elevation. Cypripedium himalaicum has been reported from as high as 4900 m in the Himalayas.


    They usually grow in light, moderate or deep shade. Cypripedium tibeticum can thrive in full sun but, in contrast, Griesbach and Asher (1983) reported that C. acaule, C. parviflorum var. parviflorum, and Cypripedium arietinum grow in deep shade on raised acid bogs and their margins. However, in other woodland species, forest clearance may allow temperate slipper orchids to persist in more open situations, but reproductive success may be much reduced. Few thrive in full sun, but C. candidum is a species of the North American prairies. Cypripedium guttatum and C. tibeticum are also commonly found in high-elevation grasslands in Asia. A number of species grow in bogs, fens or along the sides of streams. Cypripedium reginae and C. parviflorum var. parviflorum are characteristic plants of the calcareous fens of North America. Cypripedium californicum grows along turbulent mountain streams in northern California and southern Oregon and must have its rhizomes in damp soil most of the growing season. (PC).

    Images

    Distribution

    Native to:

    Alabama, Alaska, Alberta, Aleutian Is., Altay, Amur, Arizona, Arkansas, Austria, Baltic States, Belarus, British Columbia, Bulgaria, Buryatiya, California, Central European Rus, China North-Central, China South-Central, China Southeast, Chita, Colorado, Connecticut, Czechoslovakia, Delaware, Denmark, District of Columbia, East European Russia, East Himalaya, Finland, France, Georgia, Germany, Great Britain, Guatemala, Honduras, Hungary, Idaho, Illinois, Indiana, Inner Mongolia, Iowa, Irkutsk, Italy, Japan, Kamchatka, Kansas, Kentucky, Khabarovsk, Korea, Krasnoyarsk, Krym, Kuril Is., Labrador, Louisiana, Magadan, Maine, Manchuria, Manitoba, Maryland, Masachusettes, Mexico Central, Mexico Gulf, Mexico Northeast, Mexico Northwest, Mexico Southeast, Mexico Southwest, Michigan, Minnesota, Mississippi, Missouri, Mongolia, Montana, Myanmar, Nebraska, Nepal, New Brunswick, New Hampshire, New Jersey, New Mexico, New York, Newfoundland, North Carolina, North Dakota, North European Russi, Northwest European R, Northwest Territorie, Norway, Nova Scotia, Nunavut, Ohio, Oklahoma, Ontario, Oregon, Pakistan, Pennsylvania, Poland, Primorye, Prince Edward I., Qinghai, Québec, Rhode I., Romania, Sakhalin, Saskatchewan, South Carolina, South Dakota, South European Russi, Spain, Sweden, Switzerland, Taiwan, Tennessee, Texas, Tibet, Tuva, Ukraine, Utah, Vermont, Vietnam, Virginia, Washington, West Himalaya, West Siberia, West Virginia, Wisconsin, Wyoming, Yakutskiya, Yugoslavia, Yukon

    Extinct in:

    Belgium

    Recorded in error in:

    Greece

    Cypripedium L. appears in other Kew resources:

    Date Reference Identified As Barcode Type Status
    Canada K000363737
    Thomson, T. [318], India K000363689
    Hitchcock, E. [s.n.], USA K000363716
    Hitchcock, E., USA K000363715

    First published in Sp. Pl.: 951 (1753)

    Accepted by

    • Govaerts, R. (2003). World Checklist of Monocotyledons Database in ACCESS: 1-71827. The Board of Trustees of the Royal Botanic Gardens, Kew.
    • Govaerts, R. (1999). World Checklist of Seed Plants 3(1, 2a & 2b): 1-1532. MIM, Deurne.

    Literature

    Cypripedioideae: e-monocot.org
    • Pridgeon, A.M., Cribb, P.J., Chase, M.W. & Rasmussen, F.N. Genera Orchidacearum, General Introduction, Apostasioideae, Cypripedioideae. 1, 197 (Oxford University Press: Oxford, 1999).
    • Linnaeus, C. Original description of Cypripedium. (1753).at
    • Cribb, P.J. The Genus Cypripedium. 301 (Royal Botanic Gardens, Kew and Timber Press: 1997).

    Sources

    Cypripedioideae: e-monocot.org
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    Herbarium Catalogue Specimens
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    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2019. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families 2019. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0