page_title: Ragweed
section_title: Species
hierarchical_section_title: Ragweed / Species
context_page_description: Ragweeds are flowering plants in the genus Ambrosia in the aster family, Asteraceae. They are distributed in the tropical and subtropical regions of the Americas, especially North America, where the origin and center of diversity of the genus are in the southwestern United States and northwestern Mexico. Several species have been introduced to the Old World and some have naturalized and have become invasive species. Ragweed species are expected to continue spreading across Europe in the near future in response to ongoing climate change.
  Other common names include bursages and burrobrushes. The genus name is from the Greek ambrosia, meaning "food or drink of immortality".
  Ragweed pollen is notorious for causing allergic reactions in humans, specifically allergic rhinitis. Up to half of all cases of pollen-related allergic rhinitis in North America are caused by ragweeds.
  The most widespread species of the genus in North America is Ambrosia artemisiifolia.
context_section_description: There are about 50 species in genus Ambrosia. Species include:
  Ambrosia acanthicarpa Hook. – flatspine bur ragweed, annual bursage, sand bursage
  Ambrosia acuminata (Brandegee) W.W.Payne
  Ambrosia ambrosioides (Cav.) W.W.Payne – ambrosia-leaf bur ragweed, big bursage, ambrosia bursage
  Ambrosia arborescens Mill. – marko, altamisa
  Ambrosia artemisiifolia L. – common ragweed, short ragweed, Roman wormwood
  Ambrosia artemisioides Meyen & Walp.
  Ambrosia bidentata Michx. – lanceleaf ragweed, southern ragweed
  Ambrosia bryantii (Curran) Payne
  Ambrosia camphorata (Greene) W.W.Payne
  Ambrosia canescens A.Gray – hairy ragweed
  Ambrosia carduacea (Greene) W.W.Payne
  Ambrosia chamissonis (Less.) Greene – silver burr ragweed, beach-bur
  Ambrosia cheiranthifolia A.Gray – Rio Grande ragweed, South Texas ambrosia
  Ambrosia chenopodiifolia (Benth.) W.W.Payne – San Diego bur ragweed, San Diego bursage
  Ambrosia confertiflora DC. – weakleaf bur ragweed
  Ambrosia cordifolia (A.Gray) W.W.Payne – Tucson bur ragweed, heartleaf bursage
  Ambrosia deltoidea (Torr.) W.W.Payne – triangle bur ragweed, triangle bursage
  Ambrosia dentata (Cabrera) M.O.Dillon
  Ambrosia divaricata (Brandegee) Payne
  Ambrosia diversifolia (Piper) Rydb.
  Ambrosia dumosa (A.Gray) W.W.Payne – burrobush, white bursage
  Ambrosia eriocentra (A.Gray) W.W.Payne – woolly fruit bur ragweed, hollyleaf bursage
  Ambrosia flexuosa (A.Gray) W.W.Payne
  Ambrosia grayi (A.Nelson) Shinners – woollyleaf bur ragweed, lagoonweed
  Ambrosia × helenae Rouleau – Helen ragweed
  Ambrosia hispida Pursh – coastal ragweed
  Ambrosia humi León de la Luz & Rebman
  Ambrosia ilicifolia (A.Gray) W.W.Payne – hollyleaf bur ragweed
  Ambrosia × intergradiens W.H.Wagner – intergrading ragweed
  Ambrosia johnstoniorum Henrickson
  Ambrosia linearis (Rydb.) W.W.Payne – streaked bur ragweed
  Ambrosia magdalenae (Brandegee) W.W.Payne
  Ambrosia maritima L.
  Ambrosia microcephala DC.
  Ambrosia monogyra (Torr. & A.Gray) Strother & B.G.Baldwin – singlewhorl burrobrush
  Ambrosia nivea (B.L.Rob. & Fernald) W.W.Payne
  Ambrosia pannosa W.W.Payne
  Ambrosia peruviana Willd. – ragweed, altamisa
  Ambrosia × platyspina (Seaman) Strother & B.G.Baldwin
  Ambrosia polystachya DC.
  Ambrosia psilostachya DC. – Cuman ragweed, western ragweed, perennial ragweed
  Ambrosia pumila (Nutt.) A.Gray – dwarf bur ragweed, San Diego ambrosia
  Ambrosia salsola (Torr. & A. Gray) Strother & B.G. Baldwin
  Ambrosia scabra Hook. & Arn.
  Ambrosia tacorensis Meyen
  Ambrosia tarapacana Phil.
  Ambrosia tenuifolia Spreng. – slimleaf bur ragweed, lacy ambrosia
  Ambrosia tomentosa Nutt. – skeletonleaf bur ragweed
  Ambrosia trifida L. – great ragweed, giant ragweed
  Ambrosia velutina O.E.Schulz
  Ambrosia villosissima Forssk.
caption: Ambrosia chamissonis
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