Duck-meal - Spirodela polyrrhiza
MNPS Threat Rank
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 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
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.
Circumboreal through all of North America (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
- 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.