Water plant and Zostera marina

Water plant noun - A plant that grows partly or wholly in water whether rooted in the mud, as a lotus, or floating without anchorage, as the water hyacinth.

Zostera marina and water plant are semantically related. In some cases you can replace phrase "Zostera marina" with "Water plant", this phrases are similar.

Zostera marina noun - Submerged marine plant with very long narrow leaves found in abundance along North Atlantic coasts.

Water plant and Zostera marina are semantically related. You can use "Water plant" instead a noun phrase "Zostera marina".