Ageratum

Usually Ageratum ( Ageratum houstonianum ) as a bedding plant

Ageratum is a genus of flowering plants in the sunflower family ( Asteraceae). This species can be neotropisch with about 40 species. The best known species is the Common Ageratum ( Ageratum houstonianum ), which is used with some varieties as an ornamental plant in parks, gardens and window boxes.

  • 4.1 Notes and references

Description

Appearance and leaves

The Ageratum species grow as annuals to perennial herbaceous plants or subshrubs and usually reach stature heights of 20 to 120 centimeters. The upright to lying often, sparse to dense branched stems sometimes form roots at the lowest nodes ( more nodes ).

The mostly opposite, sometimes ( the top ) alternate on the stem arranged leaves are usually stalked. The simple leaf blade is elliptic, ovate or lanceolate to delta -shaped. The leaf margin is smooth to toothed. On the surfaces of leaves only one sheet of nerve can be seen and they are to more or less soft, fluffy or stiff bristly - haired bald and sometimes glandular- dotted.

Inflorescences, flowers and fruits

In dense to open, more or less zymösen, schirmtraubigen or almost doldigen total inflorescences are the basket- shaped part inflorescences. The flower heads are disc-shaped. In a at a height of 3 to 6 mm usually bell-shaped involucre are available in two or three rows of the 30 to 40 more or less identically shaped, durable, more or less herbaceous, lanceolate bracts ( Involucralblätter ), which more or less overlap and significantly hardens are and often have a trockenhäutig edge. The bracts are shorter than the flowers. The conical inflorescence base ( Rezeptaculum ) can sometimes have chaff leaves. There are no ray florets ( ray florets ) available.

The 20 to 125 florets ( = disc florets ) are hermaphroditic. The mostly white or blue to lavender petals are fused into a tube- to funnel-shaped corolla tube, which widens up more or less wide bell-shaped and ends with five Kronzähnen. The petals are externally papillose and bristly hairy and inside papilliös. The Kronzähne are about as long as wide. The anthers are truncated at its base and having at the upper end tag. Those who superior corolla tube, two pen branches are linear to club-shaped and usually strongly and densely papillose.

The prismatic and at its base, sometimes narrowed achenes are four to fünfrippig with bald or sometimes sparsely stiff - hairy bristly surface. The pappus consists of five or six free or at its base, crown-shaped fused scales; sometimes lack a pappus.

Chromosome number

The basic chromosome number is x = 10

Dissemination

The genus Ageratum has a Neotropical distribution. Species come from the USA to Mexico to Central America and South America before. Two species are cultivated and are available in many areas of the world neophytes.

System

The genus Ageratum was erected in 1753 by Carl Linnaeus in Species Plantarum, 2, pp. 839-840. As Lectotypusart 1925 Ageratum conyzoides L. was by Britton and P. Wilson in Scient. Surv. Porto Rico, 6, pp. 286 set. Synonyms for Ageratum L. are: Blakeanthus R. M. King & H. Rob. , Coelestina Cass., Caelestina Cass., Carelia Fabricius, Isocarpha Lessing non R.Brown. A homonym is Ageratum million, the 1754 as a genus in the family Plantaginaceae Juss. was published.

The genus belongs to the subtribe Ageratum Ageratinae from the tribe Eupatorieae in the subfamily herbaceous within the family Asteraceae.

In the genus Ageratum, there are about 40 species:

  • Ageratum albidum ( DC.) Hemsl.
  • Ageratum anisochroma ( Klatt ) R.M.King & H.Rob.
  • Ageratum asclepiadea R.M.King & H.Rob.
  • Ageratum ballotifolium ( Maguire, Steyerm. & Wurdack ) RMKing & H.Rob.
  • Ageratum brachystephanum rule
  • Ageratum candidum G.M.Barroso
  • Ageratum chiriquense ( B.L.Rob. ) R.M.King & H.Rob.
  • Ageratum chortianum Standlschmaus. & Steyerm.
  • Ageratum conyzoides (L.) L.: It is widespread in the Neotropics. It is sometimes cultivated. It is an invasive plant in many tropical areas of the world.
  • Ageratum cordatum ( S.F.Blake ) L.O.Williams
  • Ageratum corymbosum Zuccagni: It comes in altitudes ( 900 to ) 1200 to 1900 feet in Arizona and New Mexico as well as in Mexico before.
  • Ageratum echioides ( Less. ) Hemsl.
  • Ageratum ellipticum B.L.Rob.
  • Ageratum fastigiatum ( Gardner) R.M.King & H.Rob.
  • Ageratum gaumeri B.L.Rob.
  • Ageratum glechonophylla R.M.King & H.Rob.
  • Ageratum hondurense R.M.King & H.Rob.
  • Usually Ageratum ( Ageratum houstonianum million ): The original home ranges from southern Mexico across much of Central America. It is cultivated worldwide as an ornamental plant in some varieties. It is an invasive plant in many areas of the world.
  • Ageratum iltisii RMKing & H.Rob. It grows as a perennial herbaceous plant to subshrub. It is known only from two isolated locations in Ecuador: One of the Zamora - Loja road and the other is not described more precisely in the province of Pichincha. Due to habitat destruction, this type could be jeopardized. In the Red List of Threatened Species IUCN she is described as " Vulnerable " = " at risk " rating.
  • Ageratum isocarphoides ( DC.) Hemsl.
  • Ageratum Lavenia (L.) Kuntze
  • Ageratum lundellii R.M.King & H.Rob.
  • Ageratum maritimum Kunth: It occurs mainly on the coasts and in ( dry areas within ) Everglades in Florida as well as in the Mexican state of Quintana Roo, Belize, and the Caribbean islands of Cuba and Hispaniola before.
  • Ageratum matricarioides ( Spreng. ) Less.
  • Ageratum mexicanum Sims
  • Ageratum microcephalum ( Benth. ) Hemsl.
  • Ageratum micropappum Baker
  • Ageratum molinae R.M.King & H.Rob.
  • Ageratum munaense R.M.King & H.Rob.
  • Ageratum muticum Griseb.
  • Ageratum myriadenium ( Sch.Bip. Ex Baker ) RMKing & H.Rob.
  • Ageratum oerstedii B.L.Rob.
  • Ageratum oliveri R.M.King & H.Rob.
  • Ageratum paleaceum ( Gay ex DC. ) Hemsl.
  • Ageratum peckii B.L.Rob.
  • Ageratum petiolatum ( Hook. & Arn. ) Hemsl.
  • Ageratum platylepis ( B.L.Rob. ) R.M.King & H.Rob.
  • Ageratum rhypodes R.M.King & H.Rob.
  • Ageratum riparium B.L.Rob.
  • Ageratum salva naturae B.Smalla & N.Kilian
  • Ageratum scorpioideum Baker
  • Ageratum solisii B.L.Turner
  • Ageratum standleyi B.L.Rob.
  • Ageratum tehuacanum R.M.King & H.Rob.
  • Ageratum tomentosum ( Benth. ex Benth. ) Hemsl.

The type Ageratum stachyofolium B.L.Rob. was spun in the monotypic genus Paneroa 2008. Paneroa stachyofolia ( B.L.Rob. ) E.E.Schill. is native to the Mexican state of Oaxaca.

Swell

  • Guy L. Nesom: Ageratum, pp. 481 - Registered as text printed work: Tribe Eupatorieae, In: Flora of North America Editorial Committee ( eds.): Flora of North America North of Mexico, Volume 21 - Magnoliophyta: unranked ( in part ): Asteraceae, part 3 - Oxford University Press, New York and Oxford 2006, ISBN 0-19-530565-5. (Section Description and dissemination )
  • Yilin Chen, Takayuki Kawahara & DJ Nicholas Hind: Eupatorieae Tribus: Ageratum, pp. 883 - text the same online as printed work, In: Wu Zheng - Yi, Peter H. Raven & Deyuan Hong (Editor): Flora of China, Volume 20 - 21 - Asteraceae, Science Press and Missouri Botanical Garden Press, Beijing and St. Louis, November 12, 2011 ISBN 978-1-935641-07-0 (Section Description and dissemination ).
  • MF Porte agent: Ageratum in the New South Wales Flora Online. (Section Description and dissemination )
  • H. Robinson: Notes on Ageratum in Mesoamerica ( Eupatorieae: Asteraceae), In: Phytologia, Volume 69, Issue 2, 1990, pp. 93-104.
Asteroideae Perennial plant Umbel Pappus (flower structure) Agricultural Research Service Digital Object Identifier
34922
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