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Long-sheath Waterweed - Elodea bifoliata
Other Names:
Elodea longivaginata
State Rank Reason (see State Rank above)
Rare in Montana, where it is currently known from a few widely scattered locations across the state. Additional population and trend data are needed for the species within Montana.
General Description
Leaves opposite, 10–20 × 1.5–2.5 mm, minutely serrate, narrowly lanceolate to linear. Male flowers: spathe 2–5 cm long, inflated above; sepals 3–5 mm long; petals 4–5 mm long; stamens 7 to 9. Female flowers: spathe 3–7 cm long, slightly inflated above; sepals 2–3 mm long; petals 3–4 mm long. Capsule 8–10 mm long
(Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Phenology
Flowering in late June-July.
Diagnostic Characteristics
Elodea can be distinguished from other aquatic plants by the long-stalked, floating flowers. Elodea bifoliata can be distinguished from other members of the genus by its opposite rather than whorled leaves.
Species Range
Montana Range
Year-round
Range Comments
BC to MN south to OR, UT and NM (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Observations in Montana Natural Heritage Program Database
Number of Observations: 38
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Relative Density
Recency
(Observations spanning multiple months or years are excluded from time charts)
Habitat
Shallow water of ponds and lakes on the plains.
Ecological Systems Associated with this Species
References
- Additional ReferencesLegend:
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Catling, P.M., and W. Wojtas. 1986. The waterweeds (Elodea and Egeria, hydrocharitaceae) in Canada. Can. J. Bot. 64:1525-1541.- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
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