{{Short description|Genus of flowering plants}} {{Automatic taxobox |image = Tetragonia_tetragonioides_habit.jpg |image_caption = ''Tetragonia tetragonoides'' |taxon = Tetragonia |authority = L. |subdivision_ranks = Species |subdivision = 51, see text |subdivision_ref = <ref name = powo>[https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:16364-1 ''Tetragonia'' L.] ''Plants of the World Online''. Retrieved 30 October 2025.</ref> |synonyms = *''Demidovia'' {{small|Pall. (1781)}} *''Ludolfia'' {{small|Adans. (1763), nom. superfl.}} *''Tetragonella'' {{small|Miq. (1845)}} *''Tetragonocarpos'' {{small|Mill. (1754)}} |synonyms_ref = <ref name = powo/> |}}
'''''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.<ref name = powo/>
==Description== Plants of the genus ''Tetragonia'' are herbs or small shrubs. Leaves are alternate and succulent,<ref name=FloraBase>{{FloraBase | name = ''Tetragonia''| id = 21407}}</ref> with flowers typically yellow and small in size. Flowers can be axillary, solitary or fasciculate, greenish or yellowish in colour and mostly bisexual.<ref name=zim>{{cite web|url=http://www.zimbabweflora.co.zw/cult/genus.php?genus_id=2042|title=2403.000 Tetragonia L.|work=Flora of Zimbabwe: Cultivated plants|accessdate=21 January 2017|year=2002}}</ref> Fruit are initially succulent but become dry and woody with age.
The genus name comes from ''"tetragonus"'', meaning "four-angled" (as in a tetragon) and referring to the shape of the plants' fruits.<ref>Beadle, N.C.W., Part II, ''Students Flora of North Eastern New South Wales'', University of New England, 1972, {{ISBN|0-85834-040-2}}.</ref>
Sphaeraphides occur in at least the leaves and stalks of at least some species.{{sfn|Gulliver|1864|p=251}} Leaves are approximately kite shaped.
==Distribution== About forty species of ''Tetragonia'' are found in southern Africa, from Angola to South Africa.<ref name=zim/> They also occur in Australia,<ref name=at/> eastern Africa (Kenya and Ethiopia), western south America (Peru and Chile), and Asia (Japan, Korea, Taiwan, southern China, Myanmar, and Vietnam).<ref name = powo/>
==Classification== The genus was first formally described by the botanist Carl Linnaeus in 1753 in the work ''Species Plantarum''.<ref name=at>{{cite web|url=https://bie.ala.org.au/species/http://id.biodiversity.org.au/node/apni/2906339#names|title=''Tetragonia'' L.|accessdate=21 January 2017|work=Atlas of Living Australia|publisher=Global Biodiversity Information Facility}}</ref> Synonyms for the genus include ''Tetragonocarpos'' Mill., ''Demidovia'' Pall., and ''Tetragonella'' Miq.<ref name = powo/>
==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.<ref>{{cite web |url=http://www.plantzafrica.com/planttuv/tetragondec.htm |title = PlantZAfrica.com Homepage}}</ref>
==Species== 51 species are accepted.<ref name = powo/> {{div col}} *''Tetragonia acanthocarpa'' {{small|Adamson}} *''Tetragonia angustifolia'' {{small|Barnéoud}} *''Tetragonia arbuscula'' {{small|Fenzl}} *''Tetragonia caesia'' {{small|Adamson}} *''Tetragonia calycina'' {{small|Fenzl}} *''Tetragonia chenopodioides'' {{small|Eckl. & Zeyh.}} *''Tetragonia copiapina'' {{small|Phil.}} *''Tetragonia coronata'' {{small|Rye & Trudgen}} *''Tetragonia cristata'' {{small|C.A.Gardner ex A.M.Prescott}} *''Tetragonia crystallina'' {{small|L'Hér.}} *''Tetragonia decumbens'' {{small|Mill.}} *''Tetragonia diptera'' {{small|F.Muell.}} *''Tetragonia distorta'' {{small|Fenzl}} *''Tetragonia echinata'' {{small|Aiton}} *''Tetragonia erecta'' {{small|Adamson}} *''Tetragonia eremaea'' {{small|Ostenf.}} *''Tetragonia espinosae'' {{small|Muñoz}} *''Tetragonia fruticosa'' {{small|L.}} *''Tetragonia galenioides'' {{small|Fenzl}} *''Tetragonia glauca'' {{small|Fenzl}} *''Tetragonia halimoides'' {{small|Fenzl}} *''Tetragonia haworthii'' {{small|Fenzl}} *''Tetragonia herbacea'' {{small|L.}} *''Tetragonia hirsuta'' {{small|L.f.}} *''Tetragonia implexicoma'' {{small|(Miq.) Hook.f.}} *''Tetragonia lasiantha'' {{small|Adamson}} *''Tetragonia macrocarpa'' {{small|Phil.}} *''Tetragonia macroptera'' {{small|Pax}} *''Tetragonia maritima'' {{small|Barnéoud}} *''Tetragonia microcarpa'' {{small|Phil.}} *''Tetragonia microptera'' {{small|Fenzl}} *''Tetragonia moorei'' {{small|M.Gray}} *''Tetragonia namaquensis'' {{small|Schltr.}} *''Tetragonia nigrescens'' {{small|Eckl. & Zeyh.}} *''Tetragonia ovata'' {{small|Phil.}} *''Tetragonia pedunculata'' {{small|Phil.}} *''Tetragonia pillansii'' {{small|Adamson}} *''Tetragonia portulacoides'' {{small|Fenzl}} *''Tetragonia rangeana'' {{small|Engl.}} *''Tetragonia reduplicata'' {{small|Welw. ex Oliv.}} *''Tetragonia robusta'' {{small|Fenzl}} *''Tetragonia rosea'' {{small|Schltr.}} *''Tetragonia saligna'' {{small|Fenzl}} *''Tetragonia sarcophylla'' {{small|Fenzl}} *''Tetragonia sphaerocarpa'' {{small|Adamson}} *''Tetragonia spicata'' {{small|L.f.}} *''Tetragonia tetragonoides'' {{small|(Pall.) Kuntze}} *''Tetragonia trigyna'' {{small|Banks & Sol. ex Hook.f.}} *''Tetragonia verrucosa'' {{small|Fenzl}} *''Tetragonia vestita'' {{small|I.M.Johnst.}} *''Tetragonia virgata'' {{small|Schltr.}} {{div col end}}
===Formerly placed here=== *''Anisostigma schenckii'' {{small|(Schinz) Schinz}} (as ''Tetragonia schenckii'' {{small|Schinz}})<ref>{{cite web |title=''Anisostigma schenckii'' (Schinz) Schinz |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:360542-1 |website=Plants of the World Online |publisher=Royal Botanic Gardens, Kew |access-date=30 October 2025}}</ref>
==Gallery== <gallery> File:Tetragonia decumbens03.jpg|''Tetragonia decumbens'' File:Tetragonia echinata0.jpg|''Tetragonia echinata'' File:Tetragonia implexicoma habit.jpg|''Tetragonia implexicoma'' File:Tetragonia ovata, Aizoaceae (8464390152).jpg|''Tetragonia ovata'' </gallery>
==References== <references/>
==Bibliography== * {{cite journal |date=1864 |first=George |last=Gulliver |author-link=George Gulliver |title=Observations on Raphides and other Crystals |pages=250–252 |url=https://www.biodiversitylibrary.org/page/22249699 |journal=The Annals and Magazine of Natural History, Including Zoology, Botany, and Geology |series=Third Series |volume=14}}
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Category:Tetragonia Category:Aizoaceae genera Category:Botanical taxa named by Carl Linnaeus