Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Order: Caryophyllales
Family: Polygonaceae
Genus: Rumex
Species: R. acetosella
Binomial name: Rumex acetosella
Synonyms: Acetosella vulgaris, Acetosa acetosella
Common names: Sheep's sorrel, Common sheep sorrel, Sheep dock, Red sorrel, Sour weed, Field sorrel, Sour weed
Rumex acetosella is a species of common, flowering, perennial weed in the dock family Polygonaceae. It was originally from Europe but has been introduced almost everywhere in the world. It is most common on dry soils of low pH and fertility so it grows in dry fields, on roadsides, in sandy areas, and forest clearings. It seldom causes major problems in New Zealand as it is not a very competitive weed.
Rumex acetosella can grow a tap root down to a depth of half a metre and the superficial root system can extend a metre away from the shoot. In addition to this, the roots develop bulbils from which new individuals arise. It is poisonous but it is unusual for animals to eat enough to cause death.
Rumex acetosella grows in October a red-tinted, deeply ridged, upright, slender stem, that branch at the top, it can reach a height of 0.5 metres. It sprouts from an aggressive and spreading rhizome.
The simple, green, arrowhead-shaped leaves are small, slightly longer than 3 cm. They are smooth with a pair of horizontal lobes at the base. Their margins are entire.
The unisexual flowers develop on separate plants at the apex of the stem. The female flowers are maroon in colour and the male flowers are a yellowish-green colour.
The female flowers develop into the red-brown, roundish, three-edged, glossy achene, ca. 1 mm across. Complete road-sides can look reddish because of this seeding plant.
A female plant with flower buds.
A close up of a female flower
A young plant
Photos of the arrow-shaped leaves are below.
Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0
