Broad Waterweed - Elodea canadensis
MNPS Threat Rank
Leaves 5–12 × 1.5–2.5 mm, minutely serrate, narrowly lanceolate and opposite below to more linear and 3-whorled above. Male flowers: spathe to 15 mm long, inflated above; sepals 3–5 mm long; petals 4–5 mm long; stamens 7 to 9. Female flowers: spathe 1–2 cm long, not inflated; sepals ca. 2 mm long, purplish; petals 2–3 mm long. Capsule 5–6 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
The native Elodea canadensis has dark green leaves that are often speckled with large dark cells (DiTomaso and Healy 2003). Middle and upper leaves are opposite or 3-whorled and those below the growing tips often curve slightly downward (DiTomaso and Healy 2003). Leaves are often relatively longer and narrower in comparison to exotic species. The mid-vein of each leaf is smooth on its underside (DiTomaso and Healy 2003). Roots are more wiry when compared to Hydrilla verticillata and Egeria densa.
The exotic species of Hydrilla verticillata also have whorled leaves, but in groups of 3-12 that are 6-20 mm long and 1-4 mm wide (DiTomaso and Healy 2003). Leaves below the growing tips are often curved downward (DiTomaso and Healy 2003). The mid-vein of each leaf is smooth or minutely toothed on its underside (DiTomaso and Healy 2003).
The exotic species of Egeria densa also has whorled leaves, but in groups of 3-8 that are 15-40 mm long and 2-5 mm wide. The mid-vein of each leaf is smooth or minutely toothed on its underside (DiTomaso and Healy 2003).
Throughout most of temperate North America (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).PLACEHOLDER (field is currently blank)
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)
Axillary buds occur at nodes, at about 10 cm intervals (DiTomaso and Healy 2003).
- Additional ReferencesLegend: View Online Publication
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- DiTomaso, J.M. and E.A. Healy. 2003. Aquatic and riparian weeds of the West. Regents of University of California, Division of Agriculture and Natural Resources, Publication 3421.
- Garrett, P.A. 1983. Relationships between benthic communities, land use, chemical dynamics, and trophic state in Georgetown Lake. Ph.D. Dissertation. Bozeman, MT: Montana State University. 136 p.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.