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Montana Field Guides

Western Poison-ivy - Toxicodendron rydbergii
Other Names:  Rhus radicans, Toxicodendron radicans var. rydbergii, Rhus toxicodendron

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Native Species

Global Rank: G5
State Rank: S5
C-value: 4


Agency Status
USFWS:
USFS:
BLM:


 

External Links

 
General Description
Rhizomatous subshrub, shrub, or (rarely) vine. Stems erect, 10–50 cm, pubescent, branched and bearing leaves above. Herbage glabrous, sparsely pubescent on veins, allergenic. Leaves trifoliate, long-petiolate; leaflets ovate, remotely serrate to entire, 2–12 cm long, shiny above; lateral leaflets asymmetrical. Inflorescence an axillary, few-branched panicle. Flowers white; petals 2–3 mm long, dark-veined. Drupes crowded, globose, greenish-yellow, 4–6 mm long (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range
Montana Range Range Descriptions

Native
 


Range Comments
Much of temperate 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: 150

(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
Streambanks, woodlands, open forest; plains, valleys (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

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.
    • DuBois, K.L. 1979. An inventory of the avifauna in the Long Pines of Southeastern Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 113 p.
    • 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.
    • 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.
    • Quire, R.L. 2013. The sagebrush steppe of Montana and southeastern Idaho shows evidence of high native plant diversity, stability, and resistance to the detrimental effects of nonnative plant species. M.Sc. Thesis. Bozeman, MT: Montana State University. 124 p.
    • Sater, S. 2022. The insects of Sevenmile Creek, a pictorial guide to their diversity and ecology. Undergraduate Thesis. Helena, MT: Carroll College. 242 p.
    • Seipel, T.F. 2006. Plant species diversity in the sagebrush steppe of Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 87 p.
    • Steerey, W. F. 1979. Distribution, range use and population characteristics of Mule Deer associated with the Schafer Creek winter range, Bridger Mountains, Montana. M.Sc. Thesis. Bozeman, Montana: Montana State University. 119 p.
    • Wood, A.K. 1987. Ecology of a prairie mule deer population. Ph.D. Dissertation. Bozeman, MT: Montana State University. 205 p.
  • Web Search Engines for Articles on "Western Poison-ivy"
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Citation for data on this website:
Western Poison-ivy — Toxicodendron rydbergii.  Montana Field Guide.  .  Retrieved on , from