T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Rumex crispus (Curley dock)

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Core eudicots
Order: Caryophyllales
Family: Polygonaceae
Genus: Rumex
Species: R. crispus
Binomial name: Rumex crispus
Common name: Curley dock, Curled dock, Yellow dock, Sour dock,
Narrowleaf dock.

Rumex crispus is a perennial flowering plant native to Europe, North Africa and Western Asia. It is widely naturalised throughout the temperate world and has become a serious invasive species in many areas, including throughout North America, southern South America, parts of Australia and New Zealand. It grows in a wide variety of habitats, including disturbed soil, waste areas, roadsides, fields/meadows, shorelines, and forest edges. It spreads through the seeds contaminating crop seeds, and sticking to clothing.

Rumex crispus is similar to broad-leaved dock except for its leaves which are narrower, with crinkled edges, leaves tapered towards tip and base. Young seedlings vary in colour from entirely green to being red tinged in cooler months.
It has a large branched taproot with a pale yellow interior.
Stems are smooth, erect 0.3 to 1.2 m tall, single or in groups from the root crown. 
The leaves are alternate and oblong to lanceolate with wavy margins and are 15 to 30 cm long.

In summer flowers develop as terminal racemes or panicles. They are without petals, small, greenish, turning reddish-brown at maturity and a dark brown when dry.
Seeds are borne in a large, loose, branching cluster, > 60 cm long at the top of the stems. Each flower produces one glossy, triangular achene, about 2 mm long. A papery 3-valved or 3-winged structure surrounds the achene. The winged seeds are distributed by wind or water, can remain viable in the ground for 50 to 80 years.
Each plant can produce up to 40,000 seeds per year.

Rumex crispus seeds and vegetation are toxic to poultry and ruminants, which are most commonly affected. The toxin may occasionally affect horses. The toxic compound in Rumex crispus is a soluble oxalate. The signs of poisoning (dullness and listlessness, incoordination, weakness, and coma) can occur within 5 hours of consumption. Death can follow rapidly, generally within a day. There is no effective treatment.



Fruits of curled dock (Rumex crispus)