Orchids
Orchis sp.
Family: Orchidacea
Orchids are the largest family of the flowering plants (Angiospermae). The number of orchid species equals about four times the number of mammal species, or more than twice the number of bird species. It also encompasses about 6–11% of all seed plants. The largest genera are Bulbophyllum (2,000 species), Epidendrum (1,500 species), Dendrobium (1,400 species) and Pleurothallis (1,000 species). The family also includes the Vanilla (the genus of the vanilla plant), Orchis (type genus) and many commonly cultivated plants like some Phalaenopsis or Cattleya. Since the introduction of tropical species in the 19th century, horticulturists have more than 100,000 hybrids and cultivars. A majority of orchids are perennial epiphytes, which grow anchored to trees or shrubs in the tropics and subtropics. Other species are lithophytes, growing on rocks or very rocky soil, or are terrestrial. Nearly all temperate orchids are terrestrial. Some orchids, like Neottia and Corallorhiza, lack chlorophyll and are unable to photosynthesize. These species obtain energy and nutrients by parasitising soil fungi through the formation of orchid mycorrhizas. The fungi involved include those that form ectomycorrhizas with trees and other woody plants, parasites such as Armillaria, and saprotrophs. These orchids are known as myco-heterotrophs, but were formerly (incorrectly) described as saprophytes due to the belief that they gained their nutrition by breaking down organic matter. While only a few species are achlorophyllous holoparasites, all orchids are myco-heterotrophic during germination and seedling growth and even photosynthetic adult plants may continue to obtain carbon from their mycorrhizal fungi.
Display sign at Smithsonian Museum of Natural History
Special Collection Display at the Smithsonian Museum of Natural History: “Orchids Through Darwin’s Eyes” (February 2009)
“Forming one of the largest families of flowering plants, orchids have adapted to live in almost every type of environment around the world. Orchids helped Charles Darwin (1809-1882) formulate his theories of natural selection and evolution. Since then they have starred in many scientific studies on plant adaptations. In this gallery we will explore the alluring world of orchids, through the eyes of Darwin and those he influenced – naturalists, horticulturists, and scientists who continue to find new insights and curious surprises while working with these captivating plants in greenhouses, laboratories, and in the wild.” [ Greeting sign for the exhibit ]
Orchids at the Smithsonian Natural History Museum
Smithsonian, National Mall, Washington, D.C.
Exhibit sign at Smithsonian Museum of Natural History
Orchids at the Smithsonian Museum of Natural History
Orchids at the Smithsonian Museum of Natural History
Bibliography / More information:
- Arditti, J. 1992. Fundamentals of orchid biology. John Wiley and Sons, New York. ISBN 0471549061.
Batygina, T. B., Bragina, E. A., and Vasilyeva, E. 2003. The reproductive system and germination in orchids. Acta Biol. Cracov. ser. Bot. 45: 21–34.
Berg Pana, H. 2005. Handbuch der Orchideen-Namen. Dictionary of Orchid Names. Dizionario dei nomi delle orchidee. Ulmer, Stuttgart.
Judd, Walter S., Christopher S. Campbell, Elizabeth A. Kellogg, Peter F. Stevens, Michael J. Donoghue: Plant Systematics: A Phylogenetic Approach, Sinauer Associates Inc. 2007. ISBN 0878934073.
Kreutz, C. A. J. 2004. Kompendium der Europaischen Orchideen. Catalogue of European Orchids. Kreutz Publishers, Landgraaf, Netherlands
Ramírez, S., et al. Nature 448, 1042–1045 (2007).
D. Lee Taylor and Thomas D. Bruns: Ectomycorrhizal mutualism by two nonphotosynthetic orchids; Proc. Natl. Acad. Sci. USA; Vol. 94, pp. 4510–4515, April 1997 (on line).
Smithsonian Museum of Natural History: Special Collection (February 2009) “Orchids through the Eyes of Darwin”
Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 7, May 2006 [and more or less continuously updated since]. [1]
Strasburger, Noll, Schenck, Schimper: Lehrbuch der Botanik für Hochschulen. 4. Auflage, Gustav Fischer, Jena 1900, p. 459.
Wikipedia: Orchids
