Tetragonia is a genus of 51 species of flowering plants in the family Aizoaceae, native to temperate and subtropical regions mostly of the Southern Hemisphere, in New Zealand, Australia, southern and eastern Africa, and western South America, and eastern Asia.

Description

Plants of the genus Tetragonia are herbs or small shrubs. Leaves are alternate and succulent, with flowers typically yellow and small in size. Flowers can be axillary, solitary or fasciculate, greenish or yellowish in colour and mostly bisexual. Fruit are initially succulent but become dry and woody with age. The genus name comes from "tetragonus", meaning "four-angled" and referring to the shape of the plants' fruits.

Distribution

About forty species of Tetragonia are found in southern Africa, from Angola to South Africa. They also occur in Australia, eastern Africa (Kenya and Ethiopia), western south America (Peru and Chile), and Asia (Japan, Korea, Taiwan, southern China, Myanmar, and Vietnam).

Classification

The genus was first formally described by the botanist Carl Linnaeus in 1753 in the work Species Plantarum. Synonyms for the genus include Tetragonocarpos Mill., Demidovia Pall., and Tetragonella Miq.

Human use and cultivation

The best known species of Tetragonia is the leafy vegetable food crop, Tetragonia tetragonoides ("New Zealand spinach"). New Zealand spinach is widely cultivated as a summer leafy vegetable. Some of the other species are also eaten locally, such as Tetragonia decumbens ("Dune spinach") which is a local delicacy in its native southern Africa.

Species

51 species are accepted.

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