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Montana Field Guide

Montana Field Guides

Western Ragweed - Ambrosia psilostachya

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Native Species

Global Rank: G5
State Rank: S4S5
C-value: 4


Agency Status
USFWS:
USFS:
BLM:


 

External Links

 
General Description
Rhizomatous perennial. Stems erect, simple or branched, 10–50 cm. Herbage strigose, sometimes glandular. Leaves opposite below; blade ovate, 2–8 cm long, once pinnatifid into dentate lobes. Female heads 1-flowered. Male heads cup-shape, 2–3 mm wide, hispid, glandular with 5 to 15 florets, spreading on peduncles up to 1 mm long. Bur 2–3 mm long, ovoid, glandular, hispid (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range
Montana Range Range Descriptions

Native
 


Range Comments
Throughout North America (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 341

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat

References
  • Literature Cited AboveLegend:   View Online Publication
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Boggs, K. W. 1984. Succession in riparian communities of the lower Yellowstone River, Montana. M.S. Thesis. Montana State University, Bozeman, 107 pp.
    • Eggers, M.J.S. 2005. Riparian vegetation of the Montana Yellowstone and cattle grazing impacts thereon. M.Sc. Thesis. Montana State University, Bozeman, MT. 125 p.
    • Fritzen, D.E. 1995. Ecology and behavior of Mule Deer on the Rosebud Coal Mine, Montana. Ph.D. Dissertation. Bozeman, MT: Montana State University. 143 p.
    • King, L.A. 1980. Effects of topsoiling and other reclamation practices on nonseeded species establishment on surface mined land at Colstrip, Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 129 p.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
    • Scow, K.L. 1981. Ecological distribution of small mammals at Sarpy Creek, Montana, with special consideration of the Deer Mouse, Peromyscus maniculatus. M.Sc. Thesis. Bozeman, Montana: Montana State University. 73 p.
    • Skilbred, Chester L. 1979. Plant succession on five naturally revegetated strip-mined deposits at Colstrip, Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 128 pp.
    • Skinner, K.F. 1995. Plant and grasshopper community composition: indicators & interactions across three spatial scales. M.Sc. Thesis. Bozeman, MT: Montana State University. 144 p.
  • Web Search Engines for Articles on "Western Ragweed"
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Citation for data on this website:
Western Ragweed — Ambrosia psilostachya.  Montana Field Guide.  .  Retrieved on , from