Erigeron

Bald fleabane ( Erigeron glabratus )

The profession herbs ( Erigeron ) form a genus in the sunflower family ( Asteraceae). They comprise between 200 and 400 species worldwide. Mostly these are common in the temperate zones of the northern hemisphere ( holarctic ), and especially in North America. Native to Central Europe are only nine species. All species prefer mostly sheltered, sandy places. Some garden varieties are also referred to by all.

• 5.1 Notes and references

Description

There are annual to perennial herbaceous plants, some species are evergreen. The Stems are erect or decumbent. The leaves are always alternate, in many species the leaves are in a basal rosette. The leaves are entire, dentate to split.

The flower heads are individually or too few, rarely more. The diameter of the baskets is 5 to 35 millimeters. The bracts are available in two or three series, closely and are herbaceous until dry. The basket bottom is flat or convex, and naked. The profession herbs have tubes and ray florets. Outdoor stand in one or more rows that seldom missing, mostly 12-350 ray florets ( = ray florets ) are white to red - brownish colored and almost twice as long as the disc florets and spread outwards; they are female and fertile. The 25-450 florets ( = disc florets ) are hermaphrodite, fertile. There are usually much more available disk as daisies. The crown is usually yellow, lobed five times, the lobes sometimes purple.

The fruits are achenes, usually narrow ellipsoid to ovoid, sometimes compressed. The pappus is usually double, the outer row usually scaly or even absent, the inner row fine. Very rarely the pappus absent.

In the genus polyploidy frequently, often accompanied by agamospermy, especially in species having an odd ploidy.

Differences between Conyza and Erigeron

The distinguishing features between the two as " professional herbal " and designated on the basis of results of molecular genetic studies are not always clear in recent times, often under Erigeron combined genres. Normally, Conyza unbalanced bracts and 2 - to 20 - times as many female as hermaphrodite flowers in each head, rarely more than female hermaphrodite. The crown of the female flowers usually have no tongue, or at least this is less than one millimeter. The genus Erigeron has approximately symmetrical bracts and more androgynous than female flowers. The crown of the female flowers usually has a tongue from 2 to about 10 millimeters in length.

Diseases

Different types of vocational herbs are attacked by the rust fungus Puccinia cnici - oleracei and Puccinia dovrensis.

System

The genus was first published by Carl Linnaeus in 1753 in Species Plantarum.

Depending on the source, the genus has 200 to 400 species. The high and fluctuating figures are typical of agamosperme clans. Molecular Genetics Studies have shown that the genus might be paraphyletic, since within the monophyletic group of Conyzinae the genera Conyza, Aphanostephus and the South American Leptostelma group are.

Some types are:

• Sharp fleabane ( Erigeron acris L.):
• Erigeron alpiniformis Cronquist, is found only in Greenland.
• Alpine Fleabane ( Erigeron alpinus L.)
• One-year One year or fine blasting fleabane ( Erigeron annuus (L. ) Pers. ), A neophyte from North America.
• Himalayan fleabane ( Erigeron atticus Vill. )
• Orange fleabane ( Erigeron aurantiacus rule)
• Gold fleabane ( Erigeron aureus Greene)
• Erigeron basalticus Hoover
• Erigeron Bellidiastrum Nutt.
• Nordic fleabane ( Erigeron borealis ( Vierh. ) Simmons )
• Gold Aster fleabane ( Erigeron chrysopsidis A.Gray )
• Geteiltblättriges fleabane ( Erigeron compositus Pursh )
• Rock fleabane ( Erigeron gaudinii Brügger )
• Bald fleabane ( Erigeron glabratus Hoppe & Hornsch. Ex Bluff & Dingzhen. )
• Low fleabane ( Erigeron humilis Graham)
• Mexican fleabane, wall daisy ( Erigeron karvinskianus A.DC. )
• Unrecognized fleabane ( Erigeron neglectus Kerner )
• Einköpfiges fleabane ( Erigeron uniflorus L.)

Origin of the name

The German name is derived from invoke ( hex ). Occurred diseases, were kept for their pays wizards and witches of black magic, washes were carried out with a brew of Erigeron and medicinal herbs or the disease was " transferred " to the plant by a spell. Other Occupation herbs are, for example, the toadflax ( Linaria vulgaris), the swamp - Yarrow ( Achillea ptarmica ), the Upright Betony ( Stachys recta ) and tansy ( Tanacetum vulgare).

The botanical name is derived from Greek eri = " early" and geron = " old man " and refers to the appearing soon after flowering white hair of the fruit.

Swell

• Guy L. Nesom: Erigeron. In: Flora of North America Editorial Committee ( eds.): Flora of North America North of Mexico. Volume 20: Magnoliophyta: unranked, part 7: Asteraceae, part 2 ( Astereae, Senecioneae ), Oxford University Press, New York / Oxford et al 2006, ISBN 0-19-530564-7, p 256, online ( english).
• Anonymous: Flora of Taiwan Checklist: Erigeron.