Angiosperms (Flowering Plants) • Earth.com

Canadian pondweed

(Elodea canadensis)

galery
en

Description

Elodea canadensis (American waterweed or Canadian waterweed or pondweed) is a perennial aquatic plant, or submergent macrophyte, native to most of North America.It has been introduced widely to regions outside its native range and was first recorded from the British Isles in about 1836. The native range of the species lies within North America, but it has been introduced in many parts of the world either intentionally or not. Europe has been particularly affected with the first record dating back as far as 1836.Since then, the species' presence has been confirmed in all continental European countries. Records of the species' presence in Ireland include: County Galway, found at several sites along the Eglinton Canal, County Galway, County Down. and from the Lagan Canal near Lisburn, Northern Ireland. Young plants initially start with a seedling stem with roots growing in mud at the bottom of the water; further adventitious roots are produced at intervals along the stem, which may hang free in the water or anchor into the bottom. It grows indefinitely at the stem tips, and single specimens may reach lengths of 3 m or more. The leaves are bright green, translucent, oblong, 6–17 mm long and 1–4 mm broad, borne in whorls of three (rarely two or four) round the stem. It lives entirely underwater, the only exception being the small white or pale purple flowers which float at the surface and are attached to the plant by delicate stalks.These stalks, or hypanthea, are the lower part of the petals joined to form a floral tube. This floral tube can be up to 30 centimeters (12 inches) in length while only 1/25 inch (one millimeter) in width. for a length to width ratio of 300 fold. However, according to Wilie this ratio can sometimes be as much as one thousand fold, making this by a wide margin the skinniest of all flowers.

Taxonomic tree:

Domain:
Kingdom: Plantae
Phylum: Magnoliophyta
Class: Liliopsida
Order:Alismatales
Family:Hydrocharitaceae
Genus:Elodea
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