Slipper orchid (Cypripedium formosanum)

Description

Slipper orchid fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Slipper orchid description

The slipper orchids, which comprise around 150 species from five genera, are easily distinguished from other orchids by the slipper-like pouch formed by the lower petal ^{(2) (4) (5)}. Furthermore, unlike 99 percent of orchids, which have only one fertile stamen, the slipper orchids have two, which fuse to form a column with the style and a sterile central stamen, curiously shaped like a shield, called the staminode ^{(4) (5) (6)}. The showy flowers of Cypripedium formosanum are one to a stem and flushed pink with white and crimson spots and blotches ⁽²⁾. The leaves grow from the base and are oval shaped and pleated with prominent veins ⁽⁷⁾.

Size

Stem height: 10 - 25 cm ⁽²⁾

Slipper orchid biology

The peculiar pouch and staminode that characterise the slipper orchids are central elements to a cunning pollination strategy for this plant ^{(5) (6)}. Firstly, the fragrance of the flower or the colouration of the staminode (or a combination of the two) attracts would be pollinators, such as bees and flies. However, the shield-like staminode prevents the insects from directly accessing the flower, and frustrated individuals often fall into the pouch below. The only escape from the slippery-sided pouch is to ascend a ladder of hairs, through the column and out the base of the flower, bringing the insects into contact with the stigma and the anthers in the process ⁽⁵⁾. The newly-escaped insects inevitably end up falling foul of the same ruse, and in doing so, transfer pollen from one flower to the stigma of another ^{(4) (5) (6)}.

In common with all orchids, the seeds of slipper orchids are microscopic and lack food reserves. As a consequence, they are dependant on a symbiotic relationship with a fungus which provides the initial nutrient reserves for the seeds to germinate, and thus will only grow where the fungus is present ⁽⁵⁾.

Slipper orchid range

Cypripedium formosanum is endemic to the high mountains of Taiwan ⁽²⁾.

Slipper orchid habitat

This endangered slipper orchid occurs in forests and open damp areas in montane habitat between 2,000 and 3,000 metres above sea-level ⁽²⁾.

Slipper orchid status

Classified as Endangered (EN) on the IUCN Red List ⁽¹⁾ and listed on Appendix II of CITES ⁽³⁾.

Slipper orchid threats

Despite such an elaborate pollination strategy, the actual reproductive success rate of slipper orchids is astoundingly low, with only a small fraction of flowers ever producing seed ⁽⁶⁾. Considering the seeds that do develop are then dependant on a finely balanced relationship with a fungal partner, it is no surprise that slipper orchids are vulnerable to poor regeneration, particularly when disturbance is high ⁽⁵⁾. It does not help that because of their unusual and attractive flowers, slipper orchids are highly sought after by collectors and horticulturalists ^{(5) (6)}. In particular, Cypripedium formosanum is considered by many to be the most beautiful species in the genus ⁽²⁾.

Slipper orchid conservation

Fortunately, Cypripedium formosanum is one of the easiest slipper orchids to grow from seed and is frequently seen in cultivation ⁽²⁾. As a result, even though it is only protected on Appendix II of the Convention on International Trade in Endangered Species (CITES), which technically allows wild specimens and artificially propagated specimens to be traded under a permit, there is unlikely to be a significant demand for trade in wild plants ^{(3) (7)}. Nonetheless, in common with most Cypripediums, very little is known about its population trends and status in the wild. This information is crucial to accurately establish how threatened the remaining wild population is, and to enable the formation and implementation of conservation measures as necessary ⁽²⁾.

Find out more

For further information on the conservation of orchids see:

• Orchid Conservation International:
  www.orchidconservation.org
• Orchid Conservation Coalition:
  www.orchidconservationcoalition.org

Authentication

Glossary

Anthers

The part of the stamen (the male reproductive organ of a flower) that produces pollen.

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

Pollination

The transfer of pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.

Pollinators

Animals that in the act of visiting a plant’s flowers transfer pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.

Stamen

The male reproductive organ of a flower; comprised of an anther (the pollen-producing organ) and a filament (stalk).

Stigma

The receptive part of the female reproductive organ of a flower. Pollen germinates on the stigma.

Style

An elongatedpart of the female reproductive organs of a flower that bears the stigma (the receptive area where pollen germinates), usually at its tip.

Symbiotic relationship

Relationship in which two organisms form a close association, the term is now usually used only for associations that benefit both organisms (a mutualism)

References

1. IUCN Red List (April, 2008)
   http://www.iucnredlist.org/
2. Cribb, P. (1997) The genus Cypripedium. Timber Press, Portland.
3. CITES (April, 2008)
   http://www.cites.org
4. Royal Botanic Gardens, Kew (October, 2008)
   http://www.kew.org/scihort/orchids/index.html
5. Cribb, P. (1989) The exclusive life of the slipper orchid. New Scientist, 122(1670): 50 - .
6. Koopowitz, H. (2007) Tropical Slipper Orchids: Paphiopedilum and Phragmipedium Species and Hybrids. Timber Press, Portland.
7. McGough, H.M., Roberts, D.L., Brodie, C. and Kowalczyk, J. (2006) CITES and Slipper Orchids: An introduction to slipper orchids covered by the Convention on International Trade in Endangered Species. Royal Botanic Gardens, Kew, UK..