''Zannichellia'' (common name horned pondweed) is a genus of submerged

aquatic Aquatic means relating to water; living in or near water or taking place in water; does not include groundwater, as "aquatic" implies an environment where plants and animals live. Aquatic(s) may also refer to: * Aquatic animal, either vertebrate ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

, with threadlike

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

and tiny

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s. It is fully adapted to an aquatic

life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia *Biological life cycle, the sequence of life stages that an organism undergoes from conception to reproduction *Life-cycle hypothesis, in economics *Erikson's stages of psy ...

, including underwater

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma (botany), stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or bu ...

. There are perhaps five species, including ''

Zannichellia palustris ''Zannichellia palustris'', the horned pondweed, is a plant found in fresh to brackish waters in the United States (especially in the Chesapeake Bay), Europe, Asia, Australasia, and South America. It is recognizable by its long, thread-like leave ...

''. The genus is named after

Gian Girolamo Zannichelli Gian is a given name of Italian origin. It is a shortened version of Giovanni, another name of Italian origin. Notable people Notable people whose name is now typically expressed as Gian include: * Gian Paolo Lomazzo, Italian painter * Gian Loren ...

(1662–1729), Italian botanist.

Description

These slender plants grow submerged in water. The leaves are usually oppositely arranged and long and narrow. They have stipular sheaths. The flowers are unisexual. The male flowers have a single stamen with a slender filament and anthers that are 2-4- thecous. The female flowers have a cup-shaped membranous perianth. There are usually four carpels with a single pendulous ovule in each ovary. The stigma is shield shaped with toothed margins. The fruit is usually made of four long, dry achenes. The seeds are pendulous with a sub-cylindric embryo. The cotyledonous end is folded on itself twice.

Distribution

The species of this genus are widely distributed and are found growing in temperate and tropical regions around the world. They grow in brackish and salt water.

Selected species

The following species are accepted: *'' Zannichellia andina'' Holm-Niels. & R.R.Haynes *''

Zannichellia aschersoniana ''Zannichellia aschersoniana'' is an endangered species of aquatic plant endemic to the West Coast of the Western Cape, South Africa. Habitat and range ''Zannichellia aschersoniana'' is found between Lambert's Bay to Stilbaai in freshwater w ...

'' Graebn. *'' Zannichellia contorta'' (Desf.) Cham. *''

Zannichellia indica ''Zannichellia'' (common name horned pondweed) is a genus of submerged Aquatic plant, aquatic flowering plant, with threadlike leaf, leaves and tiny flowers. It is fully adapted to an aquatic Biological life cycle, life cycle, including underwate ...

'' Rottler ex Royle, 1840 *'' Zannichellia obtusifolia'' Talavera, García-Mur. & H.Smit *''

'' L. *'' Zannichellia pedicellata'' Buch.-Ham. ex Wall. *''

Zannichellia peltata ''Zannichellia'' (common name horned pondweed) is a genus of submerged Aquatic plant, aquatic flowering plant, with threadlike leaf, leaves and tiny flowers. It is fully adapted to an aquatic Biological life cycle, life cycle, including underwate ...

'' Bertol. *''

Zannichellia tuberosa ''Zannichellia'' (common name horned pondweed) is a genus of submerged Aquatic plant, aquatic flowering plant, with threadlike leaf, leaves and tiny flowers. It is fully adapted to an aquatic Biological life cycle, life cycle, including underwate ...

'' Lour.

References

* Potamogetonaceae Alismatales genera {{Alismatales-stub