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Montana Field Guide

Montana Field Guides

Russian Knapweed - Acroptilon repens
Other Names:  Hardheads, Turkestan Thistle, Centaurea repens, Rhaponticum repens

Noxious Weed: Priority 2B
Non-native Species

Global Rank: GNR
State Rank: SNA

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value: 0

External Links






 
General Description
Rhizomatous perennial. Stems ascending to erect, branched, 30–70 cm. Herbage: stems tomentose; leaves glabrate, punctate beneath. Leaves cauline, alternate, petiolate; blades oblanceolate, entire to pinnately lobed, 3–10 cm long, becoming smaller and sessile above. Heads discoid; involucres broadly ovoid, 9–15 mm high; phyllaries broadly ovate, green or tan below, scarious above, sharp-pointed, well imbricate in several series; receptacle flat with fine scales. Disk flowers perfect, light purple (white); corolla 11–14 mm long, slender with an expanded limb; style branches united almost to the tips. Pappus deciduous flattened bristles with plumose tips. Achenes ellipsoid, glabrous, 2–4 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range
Montana Range

Non-native
 


Range Comments
Introduced to most of temperate North America (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 2480

(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
Fields, grasslands, meadows, roadsides, most often on stream terraces; plains, valleys (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Management

References
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Citation for data on this website:
Russian Knapweed — Acroptilon repens.  Montana Field Guide.  .  Retrieved on , from