SafePlants

Two Leaf Waterweed (Elodea bifoliata)

Considerations for Pets and Children

• This aquatic plant has leaves arranged in whorls and can form dense mats, potentially posing an entanglement risk in ponds or aquariums.
• Some related waterweed species have leaves with very fine saw teeth along the margins.

Taxonomy and Nomenclature

• Scientific Name: Elodea bifoliata H. St. John
• Common Names: Two Leaf Waterweed, Two-leaf Waterweed, Twoleaf Waterweed
• Family: Hydrocharitaceae (Waterweed family)
• Kingdom: Plantae
• Synonyms: None explicitly mentioned in the provided text, but note that taxonomy of the Elodea genus is complex and evolving, with various species having overlapping common names and historical classifications.

Distribution and Habitat

• The text mentions that the name "Esthwaite Waterweed" comes from its occurrence in Esthwaite Water in northwestern England.
• Elodea is native to North and South America.
• The text references a "North America Program 2013 county distribution maps".
• The plant is associated with aquatic environments, growing completely submersed in deep water.

Morphological Characteristics and Growth Habits

• Elodea bifoliata is an aquatic plant.
• Leaves are arranged oppositely along the stem, meaning there are two leaves per node.
• Leaves are described as opposite and relatively firm.
• The leaves' shape, texture, and proportions are crucial for distinguishing it from other waterweed species.
• Stems of related species (e.g., Egeria densa) can be slender and reach a foot or two in length, or even longer.
• Leaves are dark green and arranged in whorls of two to three, becoming more crowded towards the stem tips.
• The plant can remain green throughout the winter.
• Elodea species have branched stems with oval-shaped leaves arranged in clusters.
• Elodea are herbaceous perennials.
• Related species (Egeria densa) have bright green leaves and stems.
• Elodea leaves possess only two cell layers.

Ecological Role

• The provided text indicates that some Elodea species, such as Curly Waterweed (Lagarosiphon major), are considered invasive in certain regions, such as Ireland.
• The text also refers to Brazilian waterweed as a "problem" species.

Interactions with Other Organisms

• The text mentions interactions between various Elodea species, including replacement of one species by another.
• There's a mention of possible hybrids between Elodea canadensis and Elodea nuttallii.

Further Information

• The text references county distribution maps from a North America Program (2013).
• iNat is referenced as a photo repository