It is widespread across much of North America (United States, Canada, and northern Mexico). It is also naturalized in parts of Europe, Asia, Australia, and South America. It is a common plant in many habitat types, including disturbed areas such as roadsides.
Ambrosia psilostachya is an erect perennial herb growing a slender, branching, straw-colored stem to a maximum height near two meters, but more often remaining under one meter tall. Leaves are up to 12 centimeters long and vary in shape from lance-shaped to nearly oval, and they are divided into many narrow, pointed lobes. The stem and leaves are hairy.
The top of the stem is occupied by an inflorescence which is usually a spike. The species is monoecious, and the inflorescence is composed of staminate (male) flower heads with the pistillate heads located below and in the axils of leaves.
The pistillate heads yield fruits which are achenes located within oval-shaped greenish-brown burs about half a centimeter long. The burs are hairy and sometimes spiny. The plant reproduces by seed and by sprouting up from a creeping rhizome-like root system.
This plant blooms from midsummer to autumn.
- Medicinal uses
This plant had a number of medicinal uses among several different Native American tribes, including the Cheyenne, Kumeyaay (Diegueno), and Kiowa people.  It contains a biologically active phytochemical called Psilostachyin.
- The International Plant Names Index
- The Plant List Ambrosia psilostachya DC.
- "BSBI List 2007". Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-02-25. Retrieved 2014-10-17.
- Biota of North America Program 2104 county distribution map
- United States Department of Agriculture Plants Profile . accessed 2.14.2013
- Flora of North America Vol. 21 Page 18 Ambrosia psilostachya de Candolle in A. P. de Candolle and A. L. P. P. de Candolle
- Flora of China Vol. 20-21 Page 877 裸穗豚草 luo sui tun cao Ambrosia psilostachya Candolle
- Tropicos, specimen listing for Ambrosia psilostachya DC
- Altervista Flora Italiana, Ambrosia con spighe rade, Ambrosia psilostachya DC. includes photos and European distribution map
- Atlas of Living Australia, Ambrosia psilostachya DC. Perennial Ragweed
- Neill, Robert L.; Rice, Elroy L. (October 1971). "Possible Role of Ambrosia psilostachya on Pattern and Succession in Old-Fields". American Midland Naturalist 86 (2): 344–57. JSTOR 2423628.
- University of Michigan - Dearborn; Native American Ethnobotany — Ambrosia psilostachya . accessed 2.14.2013
- Wan, Shiqiang; Yuan, Tong; Bowdish, Sarah; Wallace, Linda; Russell, Scott D.; Luo, Yiqi (2002). "Response of an allergenic species, Ambrosia psilostachya (Asteraceae), to experimental warming and clipping: Implications for public health". American Journal of Botany 89 (11): 1843–6. doi:10.3732/ajb.89.11.1843. PMID 21665612.
- United States Department of Agriculture Plants Profile for Ambrosia psilostachya (Cuman ragweed)
- Jepson Manual Treatment: Ambrosia psilostachya
- United States Department of Agriculture, National Forest Service, FEIS Ecology
- United States Geologic Survey, Northern Prairie Wildlife Profile
- Ambrosia psilostachya Calphotos Photo gallery, University of California
|Wikimedia Commons has media related to Ambrosia psilostachya.|
|This Heliantheae article is a stub. You can help Wikipedia by expanding it.|