Chenopodium is a genus of numerous species of perennial or annual herbaceous flowering plants known as the goosefoot, which occur almost anywhere in the world. It is placed in the family Amaranthaceae in the APG II system; older classification systems, notably the widely used Cronquist system, separate it and its relatives as Chenopodiaceae, but this leaves the rest of the Amaranthaceae polyphyletic. However, among the Amaranthaceae, the genus Chenopodium is the namesake member of the subfamily Chenopodioideae.

Description

The species of Chenopodium (s.str., description according to Fuentes et al. 2012) are annual or perennial herbs, shrubs or small trees. They generally rely on alkaline soil. They are nonaromatic, but sometimes fetid (foul-smelling). The young stems and leaves are often densely covered by vesicular globose hairs, thus looking farinose. Characteristically, these trichomes persist, collapsing later and becoming cup-shaped. The branched stems grow erect, ascending, prostrate or scrambling. Lateral branches are alternate (the lowermost ones can be nearly opposite). The alternate or opposite leaves are petiolate. Their thin or slightly fleshy leaf blade is linear, rhombic or triangular-hastate, with entire or dentate or lobed margins.

Inflorescences are standing terminal and lateral. They consist of spicately or paniculately arranged glomerules of flowers. Plants are monoecious (rarely dioecious). In monoecious plants flowers are dimorphic or pistillate. Flowers consist of (4–) 5 perianth segments connate, basally (at the base) or close to the middle, usually membranous margined and with a roundish to keeled back; almost always 5 stamens, and one ovary with 2 stigmas.

In fruit, perianth segments become sometimes coloured, but mostly keep unchanged, somewhat closing over or spreading from the fruit. The pericarp is membranous or sometimes succulent, adherent to or loosely covering the seed. The horizontally oriented seeds are depressed-globular to lenticular, with rounded to subacute margin. The black seed coat is almost smooth to finely striate, rugulose or pitted.

Taxonomy The genus Chenopodium was described by Carl Linnaeus in 1753 (In: Species Plantarum, Vol. 1, p. 218–222). Type species is Chenopodium album. This generic name is derived from the particular shape of the leaf, which is similar to a goose's foot: from Greek χήν (chen), "goose" and πούς (pous), "foot" or (podion), "little foot".

In its traditional circumscription, Chenopodium comprised about 170 species. Phylogenetic research revealed that the genus was highly polyphyletic and did not reflect how species were naturally related. Mosyakin & Clemants (2002, 2008) separated the glandular species as genus Dysphania (which includes epazote) and Teloxys in tribe Dysphanieae. Fuentes-Bazan et al. (2012) separated many species to genera Blitum (in tribe Anserineae), Chenopodiastrum, Lipandra, and Oxybasis (like Chenopodium in tribe Atripliceae). They included Rhagodia and Einadia in Chenopodium.

Species 132 species are currently accepted.

Chenopodium acerifolium Chenopodium aciculare Chenopodium acuminatum Willd. Chenopodium adpressifolium Chenopodium albescens Chenopodium album – white goosefoot, nickel greens, dungweed, bathua, chandali, chandaliya, fat hen, lamb's quarters, pigweed Chenopodium album var. album (synonym Chenopodium strictum Roth) Chenopodium allanii Chenopodium atripliciforme Chenopodium atrovirens – dark goosefoot, pinyon goosefoot Chenopodium attenuatum Chenopodium aureum – golden goosefoot Chenopodium auricomiforme Chenopodium auricomum – Queensland bluebush Chenopodium ayare Chenopodium baccatum (Syn. Rhagodia baccata) Chenopodium benthamii (Syn.: Rhagodia latifolia) Chenopodium berlandieri – pitseed goosefoot, southern huauzontle, lambsquarters Chenopodium berlandieri var. berlandieri (synonym Chenopodium nuttalliae ) – huauzontle, chia roja, quelit Chenopodium betaceum Chenopodium × binzianum Chenopodium × bohemicum Chenopodium × borbasii Chenopodium brandegeeae – Brandegee's goosefoot Chenopodium bryoniifolium Bunge – Korean goosefoot Chenopodium candolleanum (Syn.: Rhagodia candolleana) Chenopodium carnosulum Chenopodium chaldoranicum Chenopodium cordobense Chenopodium cornutum Chenopodium × covillei Chenopodium crusoeanum Chenopodium cuneifolium Chenopodium curvispicatum Chenopodium cyanifolium Chenopodium cycloides – sandhill goosefoot Chenopodium × dadakovae Chenopodium desertorum – desert goosefoot Chenopodium desiccatum – narrowleaf goosefoot Chenopodium detestans – New Zealand fish-guts plant Chenopodium diversifolium Chenopodium drummondii (Syn.: Rhagodia drummondii) Chenopodium eastwoodiae – Eastwood's goosefoot Chenopodium eremaeum (Syn.: Rhagodia eremaea) Chenopodium erosum R.Br. Chenopodium eustriatum Chenopodium × fallax Chenopodium ficifoliiforme Chenopodium ficifolium – fig-leaved goosefoot, small goosefoot Chenopodium flabellifolium – San Martin Island goosefoot, flabelliform goosefoot Chenopodium foggii – Fogg's goosefoot Chenopodium fremontii – Fremont's goosefoot Chenopodium frutescens Chenopodium × fursajevii Chenopodium gaudichaudianum Chenopodium giganteum D.Don (synonym Chenopodium formosanum ) – tree spinach, red quinoa, djulis Chenopodium griseochlorinum Chenopodium grubovii Chenopodium × gruellii Chenopodium harae Chenopodium hastatifolium Chenopodium × haywardiae Chenopodium hederiforme Chenopodium hians Chenopodium hircinum Chenopodium hoggarense Chenopodium howellii – Howell's goosefoot Chenopodium hubbardii Chenopodium × humiliforme Chenopodium iljinii Chenopodium incanum – mealy goosefoot Chenopodium incognitum Chenopodium indicum Chenopodium iranicum Chenopodium × jedlickae Chenopodium × jehlikii Chenopodium karoi Chenopodium khorasanica Chenopodium lenticulare Chenopodium × leptophylliforme Chenopodium leptophyllum – narrowleaf goosefoot Chenopodium × linciense Chenopodium lineatum – Mono goosefoot Chenopodium littoreum – coastal goosefoot Chenopodium lobodontum Chenopodium loureiroi Chenopodium luteorubrum Chenopodium luteum – yellow goosefoot Chenopodium × mendelii Chenopodium moquinianum Chenopodium mucronatum Chenopodium neomexicanum – New Mexico goosefoot Chenopodium nesodendron Chenopodium nevadense – Nevada goosefoot Chenopodium nitens Chenopodium nitrariaceum (F.Muell.) F.Muell. ex Benth. – nitre goosefoot Chenopodium nitens – shiny goosefoot Chenopodium novopokrovskyanum Chenopodium nutans (Syn.: Rhagodia nutans) Chenopodium oahuense – Āheahea (Hawaii) Chenopodium obscurum Chenopodium opulifolium Schrad. ex W.D.J.Koch & Ziz – grey goosefoot Chenopodium pallescens – pallid goosefoot Chenopodium pallidicaule – kañiwa, "cañahua" Chenopodium palmeri – Palmer's goosefoot Chenopodium pamiricum Chenopodium parabolicum (Syn.: Rhagodia parabolica) Chenopodium × paradoxum Chenopodium parryi – Parry's goosefoot Chenopodium perttii Chenopodium petiolare Chenopodium philippianum Chenopodium phillipsianum Chenopodium pilcomayense Chenopodium × podperae Chenopodium polygonoides Chenopodium × praeacutum Chenopodium pratericola Rydb. – pale goosefoot, desert goosefoot, narrowleaf goosefoot Chenopodium preissii (Syn. Rhagodia preissii) Chenopodium × preissmannii Chenopodium × pseudoleptophyllum Chenopodium × pseudostriatum Chenopodium pueblense Chenopodium quinoa – quinoa Chenopodium × reynieri Chenopodium robertianum (Syn.: Rhagodia hastata) Chenopodium ruiz-lealii Chenopodium sanctae-clarae Chenopodium sancti-ambrosii Chenopodium sandersii – Sander's goosefoot Chenopodium santoshei Chenopodium scabricaule Chenopodium simpsonii – Simpson's goosefoot Chenopodium × smardae Chenopodium sonorense – Sonoran goosefoot Chenopodium sosnowskyi Chenopodium spegazzinii Chenopodium spinescens (Syn. Rhagodia spinescens) Chenopodium standleyanum – Standley's goosefoot Chenopodium stenophyllum Chenopodium striatiforme Chenopodium subficifolium Chenopodium subglabrum – smooth arid goosefoot, smooth goosefoot Chenopodium suecicum – green goosefoot Chenopodium × thellungii Chenopodium tonkinense Chenopodium triandrum (Syn.: Rhagodia triandra) Chenopodium × tridentinum Chenopodium × trigonocarpum Chenopodium trigonon (Syn.: Einadia trigonos) Chenopodium twisselmannii – Twisselmann's goosefoot, high meadow goosefoot Chenopodium ulbrichii Chenopodium ulicinum Chenopodium × unarii Chenopodium × variabile (C. album × C. berlandieri) Chenopodium vulvaria – stinking goosefoot, notchweed Chenopodium wahlii – Wahl's goosefoot Chenopodium watsonii – Watson's goosefoot Chenopodium wilsonii (Syn.: Rhagodia crassifolia) Chenopodium × zahnii Chenopodium zerovii Chenopodium zoellneri

Excluded species Blitum (12 species): Blitum bonus-henricus – Good King Henry, perennial goosefoot, poor-man's asparagus, Lincolnshire spinach, markery Blitum californicum – California goosefoot, Indian lettuce Blitum capitatum – strawberry blite, blite goosefoot, strawberry goosefoot, strawberry spinach, Indian paint, Indian ink Blitum virgatum (Syn. Chenopodium foliosum) – leafy goosefoot Chenopodiastrum (5 species): Chenopodiastrum murale – nettle-leaved goosefoot Chenopodiastrum simplex – giant seed goosefoot Dysphania (about 43 glandular species, as C. botrys, C. carinatum, C. cristatum, C. melanocarpum, C. multifidium, C. pumilio and more) Lipandra (one species): Lipandra polysperma – many-seeded goosefoot Oxybasis (5 species): Oxybasis chenopodioides – small red goosefoot, saltmarsh goosefoot Oxybasis glauca – oak-leaved goosefoot Oxybasis rubra – red goosefoot, coastblite goosefoot Oxybasis urbica – upright goosefoot Teloxys (one species): Teloxys aristata Suaeda australis – austral seablite (as C. australe, C. insulare)

Ecology Certain species grow in large thickets, providing cover for small animals. Goosefoot foliage is used as food by the caterpillars of certain Lepidoptera. The seeds are eaten by many birds, such as the yellowhammer (Emberiza citrinella) of Europe or the white-winged fairy-wren (Malurus leucopterus) of Australia. Goosefoot pathogens include the positive-sense ssRNA virusesapple stem grooving virus, sowbane mosaic virus and tobacco necrosis virus.

Uses

The genus Chenopodium contains several plants of minor to moderate importance as food crops as leaf vegetables – used like the closely related spinach (Spinacia oleracea) and similar plants called quelite in Mexicoand pseudocereals. These include white goosefoot (C. album), kañiwa (C. pallidicaule) and quinoa (C. quinoa). On the Greek island of Crete, tender shoots and leaves of a species called krouvida () or psarovlito () are eaten by the locals, boiled or steamed. As studied by Bruce D. Smith, Kristen Gremillion and others, goosefoots have a history of culinary use dating back to 4000 BC or earlier, when pitseed goosefoot (C. berlandieri) was a staple crop in the Native American Eastern Agricultural Complex, and when white goosefoot was apparently used by the Ertebølle culture of Europe. Members of the eastern European Yamnaya culture also harvested white goosefoot as an apparent cereal substitute to round out an otherwise mostly meat and dairy diet c. 3500–2500 BC.

There is increased interest in particular in goosefoot seeds today, which are suitable as part of a gluten-free diet. Quinoa oil, extracted from the seeds of C. quinoa, has similar properties, but is superior in quality, to corn oil. Oil of chenopodium is extracted from the seeds of epazote, which is not in this genus anymore. Shagreen leather was produced in the past using the small, hard goosefoot seeds. C. album was one of the main model organisms for the molecular biological study of chlorophyllase.