Vallisneria americana
| Vallisneria americana | ||||||||||||
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Vallisneria americana |
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| Scientific name | ||||||||||||
| Vallisneria americana | ||||||||||||
| Michaux |
Vallisneria americana ( American water screw , giant vallisneria ) is a species of the frog-bite family(Hydrocharitaceae).
description
The leaves measure 10 to 110 × 0.3 to 1.5 centimeters. The leaf blade is divided lengthways into three zones and its edge is whole or serrate. The stem of the male flowers is 30 to 50 millimeters long and submerged. The flowers are 1 to 1.5 millimeters wide. Stamens are 2 present. The stamens have grown together at the base. The stem of female flowers is elongated so that the flowers reach the surface of the water. The flowers are usually arranged individually, less often in umbel-like clusters.
The flowering period extends from summer to autumn.
The number of chromosomes is 2n = 20.
Occurrence
Vallisneria americana grows in fresh and brackish water in rivers, lakes and bays at altitudes from 0 to 500 meters. The species is found in Canada, the USA, Mexico, the Caribbean and Central America, and Colombia.
Systematics
Vallisneria americana was first described by Michaux in 1803 . Vallisneria neotropicalis Victorin is a synonym .
literature
- Robert R. Haynes: Vallisneria americana . In: Flora of North America Vol. 22 Hydrocharitaceae ( online )
- Christel Kasselmann : aquarium plants. Ulmer Verlag, Stuttgart 1995; 2nd, revised and expanded edition 1999, ISBN 3-8001-7454-5 , p. 433 ( var. Americana ) and 434 ( var. Biwaensis ).
Individual evidence
- ^ Vallisneria americana at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
- ↑ Rafaël Govaerts (ed.): Vallisneria americana. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved August 22, 2016.
