Cypripedium acaule

Cypripedium acaule is commonly referred to in English as the pink lady's slipper or moccasin flower. ==Description==

Cypripedium acaule is a perennial plant. The plant has a solitary flower, which means only one flower blooms on its peduncle between the two large basal leaves per season. It grows slowly and up to . The flowering season in their native range is between April and June and goes dormant after fruiting. Unlike most other species of Cypripedium, the pouch of C. acaule opens in a slit that runs down the front of the labellum rather than a round opening. File:2022 Pink Lady Slipper on PEI 03.jpg|Plant in bloom near Mount Stewart, Prince Edward Island, Canada File:Cypripedium acaule fo albiflora 5515404.jpg|A form of Cypripedium acaule with a white pouch File:Cypripedium acaule 15-p.bot-cyprip.acaul-015.jpg|Side profile of flower File:Cypripedium acaule 15-p.bot-cyprip.acaul-009.jpg|Back of flower File:Cypripedium acaule 15-p.bot-cyprip.acaul-004.jpg|Leaves File:Cypripedium acaule fruiting 2015-09-14 VT USA.jpg|The fruit of Cypripedium acaule File:Cypripedium acaule 15-p.bot-cyprip.acaul-020.jpg|Cross section of fruit File:Cypripedium acaule 15-p.bot-cyprip.acaul-061.jpg|Roots File:Canada 1965 Postage Stamp - Lady’s Slipper & Prince Edward Island Arms.png|Canadian postage stamp File:Red C. acaule flower bloom in June in NWO.jpg|Red C. acaule flower bloom in June in NWO ==Taxonomy==

The genus Cypripedium is one of five genera in the subfamily of slipper orchids Cypripedioideae. Cypripedium acaule was first described in the Western European tradition by the Scottish botanist William Aiton in 1789. He referred to it as the two-leaved lady's slipper. , Kew's Plants of the World Online (POWO) does not accept any infraspecific taxa. POWO lists a dozen synonyms, one of which is Cypripedium acaule f. albiflora , a form with a white pouch and green petals. == Pollination ==

They get pollinated by attracting bees into the slit of the pink flower, but the bees eventually stop visiting them as it provides them with no benefits. Therefore, they are also called non-rewarding flowers because they offer no food or even produce any nectar but still get pollinated. The two main frequent pollinators observed visiting C. acaule are B. vagans and B. borealis queens, therefore it is believed that queen bees are their primary pollinators. The labellum in Cypripedium acuale acts like a one way trap, once a bee enters, it crawls past the pollen structure before exiting. In this process they pollinate the flower by first picking up pollen from the male counterpart and depositing it to the female counterpart. ==Distribution and habitat==

Cypripedium acaule can be found in the eastern third of the United States, particularly in the Great Lakes region and the Northeast in New Hampshire and Maine, south along the Appalachians to Alabama. It is widespread in Canada, where it is found in every province except British Columbia. It also occurs in the Northwest Territories and in Saint Pierre and Miquelon. Within its geographic range, it can be found in a wide variety of environments, from coastal plains, to pine barrens, to mountaintops. C. acaule requires highly acidic soil and tolerates a range of shade and moisture, though it prefers at least partial shade and well-drained slopes, where it can be seen in large colonies, but it also grows in deciduous woods. Since they are highly sensitive to shade and soil disturbances, they are classified as forest habitat species, which means that they are typically associated with shaded, mature forest conditions and any kinds of changes to its environment can has a potential negative impact on their population. It was long speculated that a fungal association was needed for growth, and that C. acaule could not be artificially cultivated outside of these associations. However, a greater understanding of orchids in general has shown that this association is only needed to germinate orchid seeds and is not required once plants begin making true leaves. Some disturbances that affects ''C. acaule's'' survival and population include canopy removal, forest floor and soil disturbance, all of which likely reduce the habitat suitability (shade, moisture, mycorrhizal associations). C. acaule is considered endangered in Illinois and Tennessee, Vulnerable in New York, and Unusual in Georgia. File:Cypripedium acaule 5514623.jpg|Plant growing in Sault Ste. Marie, Ontario, Canada File:Cypripède blanc.jpg|White pouch flower in Quebec, Canada ==Cultivation==

Seed germination labs have increased the commercial availability of C. acaule, although it still tends to be less commonly available than other Cypripedium species and hybrids. This is primarily due to the extra care that must be provided if the growing site is not naturally suitable for in-ground cultivation. This plant grows in soils below a pH of 5, often at 4–4.5. At this high acidity soil fungus is suppressed, and C. acaule can thrive. There is even evidence that it is partially myco-heterotrophic, parasitizing fungus that attempts to invade its roots. However, in soils above pH 5, soil microbes become more than C. acaule can manage, and the plants rot. Although, C. acaule is photosynthetic, it still relies on specific fungal partners for nutrient exchange. These fungi colonize the orchid roots and form structures called pelotons, which allows for nutrient transfer. Seedlings germinated in a sterile environment can grow and thrive in a much higher pH than 5, but must be grown below 5 if removed from the sterility. For artificial cultivation, container culture is a must, and the growing medium must be naturally acidic. Additionally, all other soil additives must be devoid of any calcium that could buffer the pH to above 5. High quality peat moss or pine duff work well, and pH neutral perlite can be added to improve porosity. Due to the risk of calcium bicarbonate, tap water is unsuitable. Rainwater or distilled water mixed with of vinegar per gallon will assure that a reliably high acidity is maintained in the growing medium. Give bright dappled shade or morning sun. Sink pots in winter or store in a cold frame for insulation. Given these conditions, C. acaule can thrive indefinitely, but it will always require much more maintenance than other species/hybrids that can be grown in a wider pH range. '' in 1793 ==References==