Nixweed-like waterweed

Nixweed-like waterweed
	Nixweed-like waterweed ( Egeria najas )
Systematics
Class :	Bedecktsamer (Magnoliopsida)
	Monocots
Order :	Frog-spoon-like (Alismatales)
Family :	Frog bite family (Hydrocharitaceae)
Genre :	Egeria
Type :	Nixweed-like waterweed
Scientific name
	Egeria najas
	Planchon

The mermaid-like waterweed ( Egeria najas ) is a species of the genus Egeria in the frog-bite family (Hydrocharitaceae). This water plant is native to South America .

description

Vegetative characteristics

The Nixkrautähnliche ( similar to the genus Najas ) waterweed is a perennial herbaceous plant and always lives completely under water. Your shoot axes are up to about 70 centimeters long. The easily breaking stems and leaves are stiff and brittle. The leaves usually sit in five-fold whorls on the leaf nodes. The light green leaves are 2 to 3 inches long and 1 to 2 millimeters wide, the edges are rough, toothed and often curved downwards.

Generative characteristics

The mermaid-like waterweed is dioeciously separated sex ( diocesan ); there are male and female plant specimens. A bract spathe encloses the buds, in the male specimens the inflorescence contains two to three flowers, in the female one or two.

The unisexual flowers have a double flower envelope . There are two green sepals and three large, white, showy petals . The male flowers contain nine stamens with 0.6 to 1.3 millimeter long stamens. The female flowers contain three styles, 0.4 to 1.3 millimeters long, which end in three-lobed stigmas.

distribution

Egeria najas is common in South America in Brazil , Uruguay , Paraguay, eastern Bolivia and Argentina . Unlike the related species Egeria densa , this aquatic plant is not an invasive plant species . Outside of its range , the mermaid-like waterweed can only be found as an aquarium plant and as a pond plant. Although Egeria najas reproduces quickly, it is partly displaced in its original range in Brazil by the introduced ground nettle Hydrilla verticillata .

literature

CD K Cook, K. Urmi-König: A revision of the genus Egeria (Hydrocharitaceae). In: Aquatic Botany , Volume 19, 1984, pp. 73-96.
Edson S. Mori, Dagoberto Martins, Edivaldo D. Velini, Celso L. Marino, Cantídio F. Gouvêa, Suzi MM Leite, Edwin Camacho, Raymond P. Guries, 2012: Genetic diversity in Egeria densa and E. najas in Jupiá Reservoir, Brazil. In: Cien. Inv. Agr. , Volume 39, 2, pp. 321-330
WTZ Sousa, SM Thomaz, KJ Murphy: Response of native Egeria najas Planch. and invasive Hydrilla verticillata (Lf) Royle to altered hydroecological regime in a subtropical river. In: Aquatic Botany , Volume 92, 1, 2010, pp. 40-48.
Christel Kasselmann : aquarium plants. Ulmer Verlag, Stuttgart 1995; 2nd, revised and expanded edition 1999, ISBN 3-8001-7454-5 , p. 277.

Web links

Commons : Nixweed-like waterweed ( Egeria najas ) - Collection of images, videos and audio files

Egeria najas in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved March 30, 2016.
Photos of herbarium specimens from the Botanical Gardens in Kew.

Individual evidence

↑ Rafaël Govaerts (ed.): Egeria najas. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved June 19, 2018.
↑ WTZ Sousa, SM Thomaz, KJ Murphy: Response of native Egeria najas Planch. and invasive Hydrilla verticillata (Lf) Royle to altered hydroecological regime in a subtropical river. In: Aquatic Botany , Volume 92, 1, 2010, pp. 40-48.

[WCSP-1] Rafaël Govaerts (ed.): Egeria najas. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved June 19, 2018.

[Sousa2010-2] WTZ Sousa, SM Thomaz, KJ Murphy: Response of native Egeria najas Planch. and invasive Hydrilla verticillata (Lf) Royle to altered hydroecological regime in a subtropical river. In: Aquatic Botany , Volume 92, 1, 2010, pp. 40-48.