Bidens cernua

Bidens cernua
Conservation status
Secure  (NatureServe)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Asterales
Family:	Asteraceae
Genus:	Bidens
Species:	B. cernua
Binomial name
Bidens cernua L.
Synonyms [1] [2] [3]
Bidens ciliolataGreene Bidens cusickiiGreene Bidens dentata(Nutt.) Wiegand Bidens elliptica(Wiegand) Gleason Bidens filamentosaRydb. Bidens gracilentaGreene Bidens graveolensKomarov 1916 not Mart. 1824 Bidens kelloggiiGreene Bidens leptomeriaGreene Bidens leptopodaGreene Bidens lonchophyllaGreene Bidens macouniiGreene Bidens marginataGreene 1901 not Perr ex DC. 1836 Bidens minimaHuds. Bidens prionophyllaGreene Bidens quadriaristata var. dentataNutt. Bidens tripartita var. minima Huds. Bidens venosaGardner Buphthalmum nutansVitman Coreopsis bidensL. Coreopsis quadricornisKrock. Coreopsis ridensGunnerus

Bidens cernua is a species of flowering plant in the aster family, Asteraceae. ^{[4] [5] [6] [7]} It is commonly called nodding beggarticks ^[8] or nodding bur-marigold.Bidens cernua is distributed throughout much of Eurasia and North America. ^{[4] [5] [6] [7] [9]}

Description

Bidens cernua is an annual species growing roughly 1m tall, with a fibrous root. Stems are rigid and often either simple or beached. Stem leaves are simple, unstalked, and opposite with saw-toothed to almost smooth margins. ^[10]

It has yellow flowers with 6-8 ray narrowly lance shaped petals around a central disk. The hemispheric heads are solitary at the ends of branches and nod with age. ^[10]

The achenes are narrowly wedge-shaped and 4-sided, flattened and ribbed. The pappus has 3-4 barbed bristles. ^[10]

Distribution and abundance

Bidens cernua is distributed throughout much of Eurasia and North America. ^{[4] [5] [7] [6]}

References

1. "The Plant List: A Working List of All Plant Species".
2. "IPNI entry for Coreopsis ridens".
3. "IPNI entry for Bidens venosa".
4. Flora of North America, Bidens cernua Linnaeus, Sp. Pl. 2: 832. 1753.
5. Flora of China, 柳叶鬼针草 liu ye gui zhen cao, Bidens cernua Linnaeus, Sp. Pl. 2: 832. 1753
6. Biota of North America Program 2014 county distribution map
7. Altervista Flora Italiana, Forbicina intera, Bidens cernua L. includes photos and European distribution map
8. Voss, E.G. (1996). Michigan Flora: A guide to the identification and occurrence of the native and naturalized seed-plants of the state. Part III: Dicots (Pyrolaceae–Compositae). Vol. Bulletin 61. Ann Arbor, Michigan, U.S.A.: Cranbrook Institute of Science and University of Michigan Herbarium.
9. BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
10. Pojar, Jim; MacKinnon, Andrew (2004). Plants of the Pacific northwest coast: Washington, Oregon, British Columbia & Alaska (Revised ed.). Vancouver: Lone Pine. ISBN   978-1-55105-530-5.