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Duck-meal - Spirodela polyrrhiza
Native Species
Global Rank:
G5
State Rank:
SNR
C-value:
7
Agency Status
USFWS:
USFS:
BLM:
External Links
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: 55
(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
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.
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