''Rumex hydrolapathum'', the great water dock, water dock, or giant water dock, is a species of

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

plants in the genus ''

Rumex The docks and sorrels, genus ''Rumex'', are a genus of about 200 species of annual, biennial, and perennial herbs in the buckwheat family, Polygonaceae. Members of this genus are very common perennial herbs with a native almost worldwide distribu ...

'' native to

fen A fen is a type of peat-accumulating wetland fed by mineral-rich ground or surface water. It is one of the main types of wetlands along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as mires. T ...

s and freshwater banks of

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and

Western Asia Western Asia, West Asia, or Southwest Asia, is the westernmost subregion of the larger geographical region of Asia, as defined by some academics, UN bodies and other institutions. It is almost entirely a part of the Middle East, and includes Ana ...

. It is the tallest species in the genus, with flowering stems attaining a height of up to . It is one of the small number of

decaploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contain ...

organisms, containing two hundred individual

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...

Description

Great water dock is a tall perennial plant reaching a height of . During its first year it has a rosette of long-stalked, hairless leaves with lanceolate leaf blades up to in length. These have smooth margins and are generally unwrinkled. These leaves are large and taper at both ends, and their lateral veins are at right angles to the midrib. In subsequent years it produces an upright flowering stem, unbranched until the base of the inflorescence. The stem is tough, grooved, green when young but turning reddish with age. Leaves growing on the stem are alternate, arching and decreasing in size higher up the stem. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is a compound

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

. The numerous small flowers are regular, with the

perianth The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower, and structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepals when ...

segments in two whorls of three, the outer whorl spreading and the inner one covering the developing fruits. There are six stamens, three fused carpels and three styles. The fruit is a triangular–ovate

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

, at first green then brown. This plant flowers from June to September.

Distribution and habitat

The great water dock is a native of Europe and western Asia. It grows beside lakes and rivers and the sea. It is usually close to the margin of the water line or growing in shallow water.

References

External links

* * {{Taxonbar, from=Q158188 hydrolapathum Flora of Europe Flora of Western Asia