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Montana Field Guide

Montana Field Guides

Small-headed Tarweed - Madia minima
Other Names:  Hemizonella minima

Potential Species of Concern

Global Rank: G4
State Rank: S3S4

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

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General Description
Small-headed tarweed is an annual with stems up to 10 cm (4 in) high, and long, slender branches from near the base. The (usually) opposite leaves, 1-2 cm long, are linear and long-pointed. Foliage is sparsely hairy below and glandular above. Small clusters of flower heads occur on the ends of the short terminal branches. Each head has 3-5 glandular, involucral bracts, 2-4 mm high, enclosing a ray flower. The yellow rays are minute, and there is a solitary, yellow disk flower surrounded by small bracts. The curved seeds (achenes), enclosed in the glandular bracts, resemble a section of orange.

Phenology
Flowering May to June, fruiting June to July.

Diagnostic Characteristics
The low, long-branched habit with small heads is diagnostic.

Species Range
Present
 


Range Comments
BC south to CA, NV, ID and MT (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Summary of Observations Submitted for Montana
Number of Observations: 31

(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
Vernally moist, often moss-covered soil on impermeable bedrock in openings of coniferous forest in the valleys and montane zone.

References
  • Additional ReferencesLegend:   View Online Publication
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    • Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Schassberger, L.A. 1991. Rare plant inventory of the East Pioneer Mountains. Prepared for the USDA Forest Service, Region 1, Beaverhead National Forest. Montana Natural Heritage Program, Helena, MT. 55 pp.
    • Schassberger, L.A. and J.S. Shelly. 1990. Sensitive plant surveys in the Bull River and adjacent drainages, USDA Forest Service, Region 1, Kootenai National Forest. Unpublished report. Montana Natural Heritage Program, Helena, MT. 60 pp.
    • Tiedemann, A. 1972. Soil properties and nutrient availability in tarweed communities of central Washington. Journal of Range Management 25(6):438-443.
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Citation for data on this website:
Small-headed Tarweed — Madia minima.  Montana Field Guide.  .  Retrieved on , from