vesinõhk

Vesimüts, scientifically known as Hydrocharis morsus-ranae, is a species of aquatic plant belonging to the family Hydrocharitaceae. The common name "vesinõhk" is derived from Estonian and refers to its appearance, with "vesi" meaning water and "nõhk" potentially referring to a frog or toad, alluding to its habitat and perhaps its floating habit.

This perennial, free-floating or rooted herb is found in stagnant or slow-moving freshwater bodies such as ponds, lakes, and ditches. It has a creeping rhizome from which erect stems arise. The leaves are typically heart-shaped or kidney-shaped, with entire margins, and are arranged in rosettes. They float on the surface of the water.

Vesimüts produces small, inconspicuous flowers. The male flowers have three white petals and are borne on short stalks, while the female flowers are solitary and have longer stalks that allow them to reach the water surface for pollination, often by insects or wind. After fertilization, the female flower stalk coils, submerging the developing fruit.

The plant is native to Europe and parts of Asia. It plays a role in aquatic ecosystems by providing habitat and food for various invertebrates and small fish. While generally not considered a problematic weed, its rapid growth can sometimes lead to dense mats that may reduce light penetration into the water, potentially impacting submerged vegetation. Control measures are usually only considered if it significantly interferes with water flow or recreational activities.