Stratiotes is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of submerged aquatic plant

Aquatic plant

Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or aquatic macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Aquatic plants can only grow in water or in soil that is...

 commonly known as water soldiers. A characteristic of the genus is the habit of the plants rising to the surface at flowering time.

Description

The leaves are serrate

Serrated blade

A serrated blade is a type of blade used on saws and on some knives or scissors. It is also known as a dentated, sawtooth, or toothed blade.A serrated blade has a cutting edge that has many small points of contact with the material being cut...

 and very brittle, breaking easily when handled. Reproduction is generally by offsets, which may number 5 or more per plant. In the UK

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, male plants have rarely if ever been recorded, although some hermaphrodite

Hermaphrodite

In biology, a hermaphrodite is an organism that has reproductive organs normally associated with both male and female sexes.Many taxonomic groups of animals do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both...

 flowers have been recorded from more southerly locations. Sexual reproduction is not known to occur.

Ecology

The plant appears to be associated with calcareous waters and there is a suggestion that changing levels of calcium carbonate

Calcium carbonate

Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...

 on the leaves may explain the floating and submerging behaviour.

The rare dragonfly

Dragonfly

A dragonfly is a winged insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera . It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body...

, the Norfolk hawker

Norfolk Hawker

Aeshna isoceles is a small hawker dragonfly that is found in Europe, mostly around the Mediterranean, and the lowlands of North Africa. Its common name in English is Green-eyed Hawker. In Britain it is a rare and local species and is known as the Norfolk Hawker...

 (Aeshna isosceles), relies on the presence of Stratiotes aloides as a food source for the smaller insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s on which it feeds.
they are very winter hardy

External links

• Invading Species.com Partnership between the Ontario Ministry of Natural Resources and the Ontario Federation of Anglers and Hunters