Taraxacum officinale

Common Dandelion
Taraxacum officinale
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Tribe: Cichorieae
Genus: Taraxacum
Species: T. officinale
Binomial name
Taraxacum officinale
F.H. Wigg

Taraxacum officinale, the Common Dandelion (often simply called "dandelion"), is a herbaceous perennial plant of the family Asteraceae (Compositae). It can be found growing in temperate regions of the world, in lawns, on roadsides, on disturbed banks and shores of water ways, and other areas with moist soils. T. officinale is considered a weedy species, especially in lawns and along roadsides, but it is sometimes used as a medical herb and in food preparation. As a nearly cosmopolitan weed, Dandelion is best known for its yellow flower heads, that turn into round balls of silver tufted fruits, that blow away on the wind.

Contents

Description

Head in full bloom

Taraxacum officinale grows from generally unbranched taproots and produces one to more than ten stems that are typically 5 to 40 cm tall but sometimes up to 70 cm tall. The stems can be tinted purplish, they are upright or lax, and produce flower heads that are held as tall or taller than the foliage. The foliage is upright growing or horizontally orientated, with leaves having narrowly winged petioles or being unwinged. The stems can be glabrous or are sparsely covered with short hairs. The 5–45 cm long and 1–10 cm wide leaves are oblanceolate, oblong, or obovate in shape with the bases gradually narrowing to the petiole. The leaf margins are typically shallowly lobed to deeply lobed and often lacerate or toothed with sharp or dull teeth. The calyculi (the cup like bracts that hold the florets) is composed of 12 to 18 segments: each segment is reflexed and sometimes glaucous. The lanceolate shaped bractlets are in 2 series with the apices acuminate in shape. The 14 to 25 mm wide involucres are green to dark green or brownish green with the tips dark gray or purplish. The florets number 40 to over 100 per head, having corollas that are yellow or orange-yellow in color. The fruits, which are called cypselae, range in color from olive-green or olive-brown to straw-colored to grayish, they are oblanceoloid in shape and 2 to 3 mm long with slender beaks. The fruits have 4 to 12 ribs that have sharp edges. The silky pappi, which form the parachutes, are white to silver-white in color and around 6 mm wide. Plants typically have 24 or 40 pairs of chromosomes but some plants have 16 or 32 chromosomes.[1] Plants have milky sap and the leaves are all basal, each flowering stem lacks bracts and has one single flower head. The yellow flower heads lack receptacle bracts and all the flowers, which are called florets, are ligulate and bisexual. The fruits are mostly produced by apomixis.[2] It blooms from March until October,[3]

Taxonomy

Ripe fruits

The taxonomy of the genus Taraxacum is complicated by apomictic and polyploid lineages,[4][5] and the taxonomy and nomenclatural situation of Taraxacum officinale is not yet fully resolved.[1] The introduced plants to North America are obligate gametophytic apomicts and triploids.[6] There are three subspecies of Taraxacum officinale including:[7]

Taraxacum officinale has historically had many English common names including: blowball, lion's-tooth, cankerwort, milk-witch, yellow-gowan, Irish daisy, monks-head, priest's-crown and puff-ball;[9] other common names include, faceclock, pee-a-bed, wet-a-bed, canker-wort,[10] and swine's snout.[11]

Carl Linnaeus named the species Leontodon Taraxacum in 1753. The genus name Taraxacum, might be from the Arabic word "Tharakhchakon",[2] or from the Greek word "Tarraxos". [12] The common name "Dandelion," comes from the French phrase "dent de lion" which means "lion's tooth", in reference to the jagged shaped foliage.[12]

Weeds

Taraxacum officinale is a common colonizer after fires, both from wind blown seeds and seed germination from the seed bank.[13] The seeds remain viable in the seed bank for many years, with one study showing germination after nine years.[14] This species is a somewhat prolific seed producer, with 54 to 172 seeds produced per head, and a single plant can produce more than 5,000 seeds a year.[14] It is estimated that more than 97,000,000 seeds/hectare could be produced yearly by a dense stand of dandelions. When released, the seeds can be spread by the wind up to several hundred meters from their source, the seeds are also a common contaminate in crop and forage seeds. The plants are adaptable to most soils and the seeds are not dependent on cold temperatures before they will germinate but they need to be within the top 2.5 centimeters of soil.[15]

Dandelion (Taraxacum officinale) has also been linked to outbreaks of stringhalt in horses.[16][17]

While not in bloom, this species is sometime confused with others, such as: Chondrilla juncea,[18] that have similar basal rosettes of foliage.

Distribution

Common Dandelion originated from Eurasia and now is naturalized throughout North America, southern Africa, South America, New Zealand, Australia, and India. It occurs in all 50 states of the USA and most Canadian provinces.[15]

Uses

A plate of sauteed dandelion greens, with Wehani rice

While the dandelion is considered a weed by most gardeners and lawn owners, the plant has several culinary uses. The specific name officinalis refers to its value as a medicinal herb, and is derived from the word opificina, later officina, meaning a workshop or pharmacy[19]. The flowers are used to make dandelion wine,[20] the greens are used in salads, the roots have been used to make a coffee-like drink and the plant was used by Native Americans as a food and medicine. [21]

Dandelions are grown commercially on a small scale as a leaf vegetable. The leaves (called dandelion greens) can be eaten cooked or raw in various forms, such as in soup or salad. They are probably closest in character to mustard greens. Usually the young leaves and unopened buds are eaten raw in salads, while older leaves are cooked. Raw leaves have a slightly bitter taste. Dandelion salad is often accompanied with hard boiled eggs. The leaves are high in vitamin A, vitamin C and iron, carrying more iron and calcium than spinach.[22]

Dandelion flowers can be used to make dandelion wine, for which there are many recipes.[23] It has also been used in a saison ale called Pissenlit (literally "wet the bed" in French) made by Brasserie Fantôme in Belgium. Another recipe using the plant is dandelion flower jam. Ground roasted dandelion root can be used as a coffee substitute. In Silesia and also other parts of Poland and world, dandelion flowers are used to make a honey substitute syrup with added lemon (so-called May-honey). This "honey" is believed to have a medicinal value, in particular against liver problems.[24]

Dandelion root is a registered drug in Canada, sold principally as a diuretic. A leaf decoction can be drunk to "purify the blood", for the treatment of anemia, jaundice, and also for nervousness. A hepatoprotective effect of chemicals extracted from dandelion root has been reported.[25] Drunk before meals, dandelion root coffee is claimed to stimulate digestive functions and function as a liver tonic. "Dandelion and Burdock" is a soft drink that has long been popular in the United Kingdom with authentic recipes sold by health food shops. It is unclear whether cheaper supermarket versions actually contain extracts of either plant.

The milky latex has been used as a mosquito repellent;[26] the milk has also been used to treat warts, as a folk remedy.[27]

Yellow or green dye colours can be obtained from the flowers but little colour can be obtained from the roots of the plant.[28]

T. officinale is food for the caterpillars of several Lepidoptera (butterflies and moths), such as the tortrix moth Celypha rufana. See also List of Lepidoptera that feed on dandelions.

References

  1. ↑ 1.0 1.1 http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=220013281
  2. ↑ 2.0 2.1 Morley, T. I. (1969). "Spring Flora of Minnesota". 1974 reprint with minor corrections (University of Minnesota Press, Minneapolis MN): 255 
  3. ↑ Rose, Francis (1981). The Wild Flower Key. Frederick Warne & Co. pp. 388,391. ISBN 0-7232-2419-6. 
  4. ↑ Wittzell, Hakan (1999). "Chloroplast DNA variation and reticulate evolution in sexual and apomictic sections of dandelions". Molecular Ecology 8 (12): 2023. doi:10.1046/j.1365-294x.1999.00807.x. PMID 10632854 
  5. ↑ Dijk, Peter J. van (2003). "Ecological and evolutionary opportunities of apomixis: insights from Taraxacum and Chondrilla". Philosophical Transactions of the Royal Society B Biological Sciences 358 (1434): 1113. doi:10.1098/rstb.2003.1302. PMID 12831477 
  6. ↑ Lyman JC, Ellstrand NC (1984). "Clonal diversity in taraxacum officinale (compositae), an apomict". Heredity 53: 1–10. doi:10.1038/hdy.1984.58. http://www.nature.com/hdy/journal/v53/n1/abs/hdy198458a.html. 
  7. ↑ http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=all&search_value=Taraxacum+officinale&search_kingdom=every&search_span=exactly_for&categories=All&source=html&search_credRating=All
  8. ↑ http://plants.usda.gov/java/profile?symbol=TAOFC
  9. ↑ Britton, N. F.; Brown, Addison (1970). An illustrated flora of the northern United States and Canada: from Newfoundland to the parallel of the southern boundary of Virginia, and from the Atlantic Ocean westward to the 102d meridian. New York: Dover Publications. pp. 315. ISBN 0-486-22644-1. 
  10. ↑ www.nps.gov/akso/NatRes/EPMT/Species_bios/Taraxacum%20officinale.pdf
  11. ↑ Loewer, Peter (2001). Solving weed problems. Guilford, Conn.: Lyons Press. pp. 210. ISBN 1585742740. http://books.google.com/?id=5M1GqKyIiEoC&pg=PA210&lpg=PA210&dq=Swine%27s+Snout 
  12. ↑ 12.0 12.1 Kowalchik, Claire; Hylton, William H.; Carr, Anna (1987). Rodale's illustrated encyclopedia of herbs. Emmaus, Pa.: Rodale Press. pp. 141. ISBN 0-87857-699-1. 
  13. ↑ http://www.fs.fed.us/database/feis/plants/forb/taroff/all.html
  14. ↑ 14.0 14.1 http://en.wikipedia.org/w/index.php?title=Taraxacum_officinale&action=edit&section=3
  15. ↑ 15.0 15.1 http://akweeds.uaa.alaska.edu/pdfs/species_bios_pdfs/Species_bios_TAOF.pdf
  16. ↑ Australian stringhalt Retrieved on 5 March 2009
  17. ↑ http://www.theveterinarian.com.au/clinicalreview/article793.asp
  18. ↑ http://www.nwcb.wa.gov/weed_info/Chondrilla_juncea.html
  19. ↑ Stearn, W.T. 1992. Botanical Latin: History, grammar, syntax, terminology and vocabulary, Fourth edition. David and Charles.
  20. ↑ http://www.cooks.com/rec/search/0,1-00,dandelion_wine,FF.html
  21. ↑ Clarke, Charlotte Bringle (1977). Edible and useful plants of California. Berkeley: University of California Press. pp. 191. ISBN 0-520-03261-6. 
  22. ↑ Common Dandelion
  23. ↑ winemaking: Dandelion Wines
  24. ↑ Wera Sztabowa, "Krupnioki i moczka, czyli gawędy o śląskiej kuchni", Wydawnictwo Śląsk, Katowice, 1990, ISBN 83-216-0935-X.
  25. ↑ A. Mahesh, R. Jeyachandran, L. Cindrella, D. Thangadurai, V. P. Veerapur, D. Muralidhara Rao (2010). Hepatocurative potential of sesquiterpene lactones of Taraxacum officinale on carbon tetrachloride induced liver toxicity in mice. Acta Biologica Hungarica 61(2):175-190. abstract
  26. ↑ Plantwatch - Plants
  27. ↑ Dandelion - The Natural History Museum - Country Cures
  28. ↑ A. Dyer (1976) Dyes from natural sources. G. Bell & Sons Ltd., London
Wikiversity has bloom time data for Taraxacum officinale on the Bloom Clock

External links