Dandelion (taraxacum)
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Taraxacum sect. Mongolica : Taraxacum albidum |
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Dandelion ( Taraxacum ) is a plant genus within the family of the daisy family (Asteraceae). Their best-known species is the common dandelion , which is also very common in Central Europe , the "dandelion", "butter" or "cow flower". The genus Taraxacum should not be confused with the very similar genus Leontodon within the same family, which is usually named the same in German .
description
The representatives of the genus are perennial , herbaceous plants that reach stature heights of (rarely 5 to) usually 30 to 40 (rarely during fruiting up to 60) cm. They contain a white milky sap in all parts of the plant . The tap roots merge into short, strongly compressed shoot axes , on which the leaves are densely arranged in basal rosettes . The leaves are ovate to lanceolate and slightly to heavily lobed, incised and serrated.
Many of the features are plastic and can vary widely. The shape of the leaves of a single plant varies greatly depending on the amount of precipitation, solar radiation and the season in which the leaf is formed.
Hollow inflorescence stalks arise from the leaf axils , each of which has a single, cup-shaped inflorescence ( pseudo-flower ) over tightly screwed bracts . The flower heads are 8 to 40 mm in diameter. Two (or rarely three) whorl with a total of seven to 25 bracts envelop initially the bud to open and then close with the inflorescence . The inflorescence base is flat, plate-shaped. An inflorescence usually contains 20 to 150 (in rare cases only 15) ray florets. The color of the ray florets ranges from yellowish white to yellowish orange, sometimes greenish, depending on the species, often with purple to gray stripes on the outside. The anthers are yellow to creamy yellow, sometimes darker. The styles are yellow or greenish, sometimes greyish to blackish.
The four- to twelve- (up to 15-) ribbed achenes are straw- to olive-colored, brown, red, light to dark gray. Your pappus has a wreath of 50 to over 105 white to cream-colored to yellow, feathery bristle hairs. With the hairy parachutes, the achenes are spread by the wind ( paragliders ).
distribution
Dandelion plants are found worldwide from the tropics to the polar regions . They reach their greatest diversity in cooler areas of the temperate zones .
Systematics
Only a relatively small number of populations can be recorded using conventional concepts of a species . These plants are mostly diploid (2n = 16), sometimes also polyploid , but only ever occur in one ploidy level and reproduce sexually in the usual way.
In the vast majority of populations, however, there are several levels of ploidy that interact in a complex manner and one of which is apomictic, i.e. producing seeds without prior fertilization . The problem of dividing these plants into species is exemplified by the common dandelion . Because of the problem, many former species have already been placed in collective species , but since these too can hardly be separated from one another due to the large number of transition populations, they are now grouped into sections. In addition to a few “good” species, there are currently a large number of plants that can only be identified and named by their approximate systematic position .
The number of species to be recognized in the genus varies between a few tens and several thousand, depending on the author.
Sections and types (selection)
- Taraxacum sect. Australasica Kirschner , Scarlett & Štěpánek
- Taraxacum sect. Biennia R. Doll
- Taraxacum sect. Borea Sahlin ex AJRichards
- Taraxacum sect. Borysthenica Kirschner & Štěpánek
- Taraxacum sect. Celtica A.J. Richards : Bog dandelion; Taraxacum duplidentifrons , Taraxacum gelertii
- Taraxacum sect. Ceratophora ( Hand.-Mazz. ) APKhokhr.
- Taraxacum sect. Confusa Kirschner & Štěpánek
- Taraxacum sect. Dioszegia (Heuff.) Heuff. (= Taraxacum sect. Serotina Soest ): Loess dandelion
- Taraxacum sect. Erythrosperma (H. Lindb.) Dahlst. : Callous dandelion; Taraxacum bellicum , Taraxacum brachyglossum , disseminatum Taraxacum , divulsum Taraxacum , Taraxacum lacistophylloides , lacistophyllum Taraxacum , magnolevigatum Taraxacum , Taraxacum multiglossum , Taraxacum parvilobum , proximum Taraxacum , rubicundum Taraxacum , scanicum Taraxacum , parnassicum Taraxacum , plumbeum Taraxacum , tanyolobum Taraxacum , tenuilobum Taraxacum , Taraxacum tortilobum
- Taraxacum sect. Hamata H.Øllg. : Hook dandelion; Taraxacum hamatiforme
- Taraxacum sect. Macrocornuta Soest : This is where the Russian dandelion ( Taraxacum kok-saghyz L.E. Rodin ) belongs.
- Taraxacum sect. Mongolica ( Dahlst. ) R.Doll : Taraxacum albidum
- Taraxacum sect. Palustria Dahlst. : Swamp dandelion; Taraxacum palustre agg., Taraxacum anserinum , Taraxacum balticiforme , Taraxacum bavaricum , Taraxacum heleonastes , Taraxacum hollandicum , Taraxacum madidum , Taraxacum multilepis , Taraxacum turfosum
- Taraxacum sect. Taraxacum (Syn .: Taraxacum sect. Ruderalia Kirschner, H.Øllg. & Štěpánek ): common dandelion , hook-lobed dandelion, strict dandelion; Taraxacum officinale agg., Taraxacum acervatulum , acrophorum Taraxacum , Taraxacum adiantifrons , Taraxacum aequilobum , aganophytum Taraxacum , Taraxacum alatum , amplum Taraxacum , Taraxacum ancistrolobum , baeckiiforme Taraxacum , borgvallii Taraxacum , Taraxacum brevisectoides , Taraxacum caloschistoides , canoviride Taraxacum , Taraxacum concinnum , Taraxacum demotes , Taraxacum ekmanii , exsertiforme Taraxacum , fasciatum Taraxacum , Taraxacum guttigestans , haematicum Taraxacum , hepatic Taraxacum , lacinulatum Taraxacum , longisquameum Taraxacum , mimulum Taraxacum , oblongatum Taraxacum , Taraxacum oinopolepis , oxyrhinum Taraxacum , pallescentiforme Taraxacum , Taraxacum paradoxachrum , paucijugum Taraxacum , pectinatiforme Taraxacum , Taraxacum perfissum , Taraxacum plicatiangulatum , Taraxacum porrigens , Taraxacum procerum , Taraxacum pulchrifolium , Taraxacum quadrangulum , Taraxacum sahlinii , Taraxacum selenoides , Taraxacum severum , Taraxacum sphenolobum , Taraxacu m subcanescens , Taraxacum subgentiliforme
Possible confusion
The species from the genus Leontodon , which are also named dandelions, and common piglet weed are very similar. However, the inflorescence stalks of these plants are not hollow. In contrast to the genus Taraxacum , in which the achenes equipped with hairy parachutes are paragliders , in the genus Leontodon the achenes are not beaked, ie the pappus does not sit on a stem. The yellowish-white to light brown bristle hairs of the pappus are covered with small hairs ( feathered ); they stand in one or two rows. The bristle hairs of the outer ring can be reduced to bristle scales.
literature
- Theodore M. Barkley, Luc Brouillet, John L. Strother: Asteraceae in Flora of North America. 19, 2006, page 239: Taraxacum - Online.
- Friedrich Heinrich Wiggers: Taraxacum. In: Primitiae Florae Holsaticae. 56, 1780
- Reinhard Doll: The genus Taraxacum. Westarp Sciences, 1974
- Adrian John Richards: Sectional Nomenclature in Taraxacum (Asteraceae). In: Taxon. 4, No. 34, 1985, pp. 633-644
- Ingo Uhlemann, Jan Kirschner, Jan Stepanek: Taraxacum , In: Rothmaler: Exkursionsflora von Deutschland - Vascular Plants, Critical Supplementary Volume. 11th edition, Berlin, Heidelberg (Springer Spectrum), 2016, pp. 133-184.
Individual evidence
- ↑ a b Werner Greuter (2006+): Compositae (pro parte majore). - In: W. Greuter & E. von Raab-Straube (ed.): Compositae. Euro + Med Plantbase - the information resource for Euro-Mediterranean plant diversity. Datasheet Taraxacum In: Euro + Med Plantbase - the information resource for Euro-Mediterranean plant diversity.
