Fleabane Herbs (Conyza)

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Professional herbs
South American fleabane (Conyza boranensis)

South American fleabane ( Conyza boranensis )

Systematics
Euasterids II
Order : Astern-like (Asterales)
Family : Daisy family (Asteraceae)
Subfamily : Asteroideae
Tribe : Astereae
Genre : Professional herbs
Scientific name
Conyza
Less.

The erigeron ( Conyza ) are a genus within the family of the daisy family (Asteraceae). A common German name , like the closely related genus Erigeron, is “professional herbs”. From a systematic point of view, Conyza has often been incorporated into the genus Erigeron ; to distinguish the German names Conyza is also called Katzenschweif ; The name “Feinstrahl” can also be used for Erigeron . The genus Conyza is distributed with 25 to 155 species in the temperate and warmer areas, especially the New World .

description

Vegetative characteristics

Conyza are annual to perennial herbaceous plants , rarely shrubs or small trees . The alternate leaves are usually lanceolate, with entire margins to toothed or lobed.

Generative characteristics

In umbrella-shaped or annual total inflorescences, there are rather small, cup-shaped partial inflorescences in several to very numerous groups, rarely only a single flower head is present. The bottom of the cup is flat to slightly curved and mostly bare. The involucre is bell-shaped to urn-shaped. The bracts are in two to four rows, more or less overlapping, rarely herbaceous and soon protruding far. The ray-florets are numerous, their crown very narrow. They are female and stand in several rows. Your crown is tubular to thread-shaped. The tubular flowers are hermaphroditic or functionally male.

In contrast to the genus professional herbs ( Erigeron ), the ray florets are very short and the cups are only a few millimeters in diameter. The ray flowers are mostly whitish in color, but they can also be yellowish or purple. The tubular flowers are hermaphroditic or sometimes functionally male, usually a few, tubular flowers with (four to) five lobes.

The achenes are obovate to elongated, sometimes compressed, usually hairy. The pappus consists of many fine, fragile bristles.

Differences between Conyza and Erigeron

The distinguishing features between the two genera known as occupational herbs are not always clear. Conyza usually has asymmetrical involucral leaves and two to twenty times as many feminine as hermaphrodite flowers in each head, rarely more hermaphroditic than feminine. The crown of the female flowers usually have no tongue or it is at least shorter than 1 millimeter. The genus Erigeron has approximately symmetrical involucral leaves and more hermaphroditic than female flowers. The crown of the female flowers usually has a tongue from 2 to over 10 millimeters.

Systematics and distribution

The genus Conyza was established by Christian Friedrich Lessing .

There are 25 to 155 species depending on the source. According to molecular biological studies, the genus should be classified under the genus Erigeron . Conyza himself is likely to be polyphyletic, or at least paraphyletic.

The genus Conyza is mainly tropical and subtropical, both in the Old and New World. There are about two types of neophytes in Europe : South American fleabane ( Conyza bonariensis ; frequently naturalized in the Mediterranean area, rarely also in Central Europe.) And Whitish fleabane ( Conyza sumatrensis ; frequently naturalized in the Mediterranean area, increasingly also in Central Europe.)

Habitus and flower heads of Conyza glandulitecta
Flower heads of Conyza monorchis

For example, no longer belongs to the genus Conyza :

  • Conyza bonariensis (L.) Cronquist → Erigeron bonariensis L.
  • Canadian fleabane ( Conyza canadensis (L.) Cronquist ) → Erigeron canadensis L.
  • Conyza floribunda Kunth → Erigeron floribundus (Kunth) Sch. Gdp.
  • Conyza ramosissima Cronquist → Erigeron divaricatus Michx.

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Individual evidence

  1. ^ Robert Zander : Zander. Concise dictionary of plant names. Edited by Walter Erhardt , Erich Götz, Nils Bödeker, Siegmund Seybold . 17th edition. Eugen Ulmer, Stuttgart 2002, ISBN 3-8001-3573-6 .
  2. ↑ a b c d e f John L. Strother: Conyza , p. 348 - the same text online as the printed work , In: Flora of North America Editorial Committee (ed.): Flora of North America North of Mexico , Volume 20: Magnoliophyta: Asteridae (in part): Asteraceae, part 2 , Oxford University Press, New York and Oxford, 2006. ISBN 0-19-530564-7
  3. ^ Bochum Botanical Association: Contributions to the flora of North Rhine-Westphalia from 2013. Yearbook of the Bochumer Botanical Association. Vol. 5, 2014, pp. 130–163 ( PDF 6.4 MB)
  4. ^ A b c Conyza in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved January 16, 2019.

Web links

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