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Montana Field Guides

Duck-meal - Spirodela polyrrhiza

Native Species

Global Rank: G5
State Rank: SNR
C-value: 7


Agency Status
USFWS:
USFS:
BLM:


 

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General Description
Fronds obovate to orbicular, flattened, 3–8 mm long, attached together in groups of 3 to 10, green. Roots 1–3 cm long, several from each frond. Inflorescence a flower-bearing pouch on each side of the frond that also serves as point of attachment to other fronds. Seeds 1 or 2, ribbed or smooth (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Diagnostic Characteristics
Montana species of the Duckweed Family are all small, perennial, free-floating, aquatic herbs. In this family the term "leaf" cannot be used because a leaf consists of a stem (petiole) and a blade (Landolt in FNA 2000). Instead the term "frond" is used. Be aware that species can grow in the same place naturally.

Lemna - Duckweed, native
* Fronds: Green above and mostly below.
* Root: 1 per frond, sometimes absent.
* Veins: 1-3 per frond.

Spirodela - Duck-meal, native
* Fronds: Green above and usually purplish below.
* Roots: 2 or more per frond
* Veins: 3 or more per frond.

Wolffia - Water-meal, native
* Fronds: Green to brown; round.
* Root: 0; absent.
* Veins: 0; absent.

Range Comments
Circumboreal through all of 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: 57

(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
Fresh water of ponds, lakes, often with Lemna minor (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?
    • 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.
  • Web Search Engines for Articles on "Duck-meal"
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Citation for data on this website:
Duck-meal — Spirodela polyrrhiza.  Montana Field Guide.  .  Retrieved on , from