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Montana Field Guide

Montana Field Guides

Western Ragweed - Ambrosia psilostachya


Global Rank: G5
State Rank: S4S5

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value: 3

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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 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range
Present
 


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

Summary of Observations Submitted for Montana
Number of Observations: 3

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Relative Density

Recency

 

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



Habitat

References
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Citation for data on this website:
Western Ragweed — Ambrosia psilostachya.  Montana Field Guide.  .  Retrieved on , from