Dock

Dock, common name for a group of about 200 species of herbaceous plants of the knotweed family, widely distributed in temperate areas of the world. Dock plants usually have stout tap roots and large basal leaves. The flowers lack petals and are individually inconspicuous, but they are often brightly coloured and borne in dense clusters. Most species are weeds. Great water dock, which grows to 2 m (6 ft), is sometimes cultivated for landscaping; the leaves of curly dock and patience dock are used as green vegetables. Many of the smaller docks are better known as sorrels. The leaves of French sorrel are used as a salad garnish. The distinctive sour taste is due to the presence of oxalic acid, which can be poisonous in high concentrations, as in the leaves of rhubarb.

Scientific classification: Docks belong to the knotweed family Polygonaceae. Great water dock is classified as Rumex hydrolapathum, curly dock as Rumex crispus, patience dock as Rumex patientia, and French sorrel as Rumex scutatus.