Annual to perennial herbs. Leaves opposite or alternate, simple; stipules often present. Flowers axillary, usually small and inconspicuous, solitary or in crowded cymes, monoecious or dioecious, unisexual or bisexual, hypogynous, actinomorphic. Perianth segments of one whorl of 4, often partly fused at base, greenish or brownish. Male flowers with 4 stamens, inserted opposite the perianth segments, rudimentary ovary often present; anthers 2-celled, opening lengthwise. Female flowers with a 1-celled ovary with 1 ovule; style 1, the stigma much-branched; fruit an achene, the seed usually with endosperm.

Consists of about 45 genera and over 700 species, mostly in the tropics or subtropics with a few species in cooler parts of the world.

Urtica L.

Annual or perennial, monoecious or dioecious, unisexual or bisexual herbs, mostly with stinging hairs. Stems erect, ridged or 4-angled. Leaves opposite, toothed, with free stipules. Inflorescence axillary, spike-like, with clustered cymes. Perianth segments 4, free; female flowers with the 2 inner longer than the 2 outer and enclosing the fruit. Stamens 4. Style 1; stigma much-branched. Fruit an achene.

Contains about 50 species in temperate regions. In the past nettles have had a large number of useful attributes. The Romans certainly ate nettles and on our Celtic fringe nettles have been traditionally eaten with oatmeal in a soup, while ‘St Columba's broth’ tastes remarkably like soup made from young peas. The young tops can be used as a green vegetable, usually in the form of a purée like spinach, but they have an earthy flavour. In Scotland nettle pudding was made with leeks and onions, broccoli or cabbage with rice, boiled in a muslin bag and served with butter and gravy. During the Second World War schools collected great quantities of nettles for medicinal use. Painful joints were formally stung with nettles to warm the joint and relieve the pain of arthritis.