Encyclopedia of Earth

Amaranthaceae: The pigweed family

Content Cover Image

Celosia caracas (By Diego Menna (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons)

Amaranthaceae is a plant family in the order Caryophyllales that is native to tropical America and Africa, ranging between tropics and sub-tropics to more temperate regions. The family is believed to have originated in either the southwestern region of the United States, Latin America, or Africa. The Amaranthaceae family is dominated by herbs but also includes vines, shrubs and trees, and is comprised of approximately 800 species represented by 60 plus genera and broadly divided into two sub families (Amaranthoideae and Gomphrenoideae).

Physical Description

Leaves are mostly simple and entire, non-stipulate, phyllotaxy is alternate/opposite. Flowers are regular, cyclic, tiny, and characterized by spiny perianth with conspicuous bracts and bractlets and are either unisexual/bisexual (hermaphrodite), solitary/aggregated into inflorescence (spikes/cymes/heads) (Fig 1). Calyx presents with 3-5 sepals, corolla with 3-5 petals, androecium with 5 stamens, gynoecium with pistil having 2-3 carpels, 1-3 styles, ovule campylotropus, ovary-superior with one chamber enclosing one to several ovules, placentation basal. Fruits are fleshy/non-fleshy, dehiscent/non-dehiscent, capsule/berry/nutlet/drupe. Seeds are small and numerous, black/light to dark brown/reddish brown in color, commonly globose/sub-globose/lenticular in shape. Pollen gains monosiphonous and multi-aperturate.

Figure 1. Top and intermediate layers show ornamental plants of the genus Celosia;
bottom layer shows pigweed representing genus Amaranthus. (Saikat Basu, own work)

Economic Importance

The Amaranthaceae family has many economically important plant species, including ornamentals (eg. Iresine, Celosia, Gompphrena, Amaranthus etc), weeds (eg. infamous pigweeds like Amaranthus retroflexus, A. albus, A. graecizans etc), protein rich, white-seeded grain species (A. caudatus, A. cruentus etc) and several others (Table 1). Important secondary metabolites include different alkaloids, saponins, sapogenins, flavonols, betalins etc. The family is interesting in terms of photosynthesis variations among the members since some show preference for either C3 or C4 cycles while some others are C3-C4 intermediates.

The members of Amaranthaceae family are presented in table 1.

Table 1. Members of the Amaranthaceae family



Species & accepted Taxa



USDA, 2014

Achyranthes aspera L.

Achyranthes L.


USDA, 2014

Achyranthes atollensis H. St. John

USDA, 2014

Achyranthes canescens R. Br.

USDA, 2014

Aerva javanica (Burm. f.) Juss. ex Schult.

Aerva Forssk.

USDA, 2014

Aerva lanata (L.) Juss. ex Schult.

USDA, 2014

Aerva sericea Moq.

USDA, 2014

Alternanthera bettzichiana (Regel) Voss

Alternanthera Forssk.

USDA, 2014

Amaranthus acanthochiton Sauer

Amaranthus L.

USDA, 2014

Amaranthus albus L.

USDA, 2014

Blutaparon vermiculare (L.) Mears

Blutaparon Raf.

USDA, 2014

Celosia argentea L.

Celosia L.

USDA, 2014

Celosia nitida Vahl

USDA, 2014

Chamissoa altissima (Jacq.) Kunth

Chamissoa Kunth

USDA, 2014

Charpentiera densiflora Sohmer

Charpentiera Gaudich.

USDA, 2014

Charpentiera tomentosa Sohmer

USDA, 2014

Cyathula prostrata (L.) Blume

Cyathula Blume

USDA, 2014

Deeringia amaranthoides (Lam.) Merr.

Deeringia R. Br.

USDA, 2014

Digera muricata (L.) Mart.

Digera Forssk.

USDA, 2014

Froelichia arizonica Thornb. ex Standl.

Froelichia Moench

USDA, 2014

Gomphrena caespitosa Torr.

Gomphrena L.

USDA, 2014

Gomphrena nitida Rothr.

USDA, 2014

Gossypianthus lanuginosus (Poir.) Moq.

Gossypianthus Hook.

USDA, 2014

Guilleminea densa (Humb. & Bonpl. ex Schult.) Moq.

Guilleminea Kunth

USDA, 2014

Hermbstaedtia odorata (Burch.) T. Cooke

Hermbstaedtia Rchb.

USDA, 2014

Iresine argentata (Mart.) D. Dietr.

Iresine P. Br.

USDA, 2014

Iresine lindenii Van Houtte

USDA, 2014

Lithophila muscoides Sw.

Lithophila Sw.

USDA, 2014

Nototrichium divaricatum D.H. Lorence

Nototrichium (A. Gray) Hillebr.

USDA, 2014

Nototrichium sandwicense (A. Gray) Hillebr.

USDA, 2014

Pfaffia grandiflora (Hook.) R.E. Fries

Pfaffia Mart.

USDA, 2014

Philoxerus portulacoides A. St. Hil.

Philoxerus R. Br.

USDA, 2014

Psilotrichum trichotomum Blume

Psilotrichum Blume

USDA, 2014

Tidestromia carnosa (Steyerm.) I.M. Johnst.

Tidestromia Standl.

USDA, 2014

Tidestromia gemmata I.M. Johnst.

USDA, 2014

Tidestromia lanuginosa (Nutt.) Standl.


References and Further Readings

  • Akhani H, Edwards G, Roalson EH (2007) Diversification Of The Old World Salsoleae s.l. (Chenopodiaceae): Molecular Phylogenetic Analysis Of Nuclear And Chloroplast Data Sets And A Revised Classification. International Journal of Plant Sciences, 168(6): 931-956. doi: 10.1086/518263
  • Carolin RC (1983) The trichomes of the Chenopodiaceae and Amaranthaceae. Bot. Jahrb. Syst. 103: 451-466.
  • Eliasson UH (1988) Floral morphology and taxonomic relations among the genera of Amaranthaceae in the New World and the Hawaiian Islands. Bot. J. Linn. Soc., 96: 235-283.
  • Kadereit G, Mavrodiev EV, Zacharias EH, Sukhorukov AP (2010) Molecular phylogeny of Atripliceae (Chenopodioideae, Chenopodiaceae): Implications for systematics, biogeography, flower and fruit evolution, and the origin of C4 Photosynthesis. - American Journal of Botany, 97(10):1664-1687. doi: 10.3732/ajb.1000169.
  • Kadereit G, Mucina L, Freitag H (2006) Phylogeny of Salicornioideae (Chenopodiaceae): diversification, biogeography, and evolutionary trends in leaf and flower morphology. Taxon, 55(3): 617-642.
  • Mahbubur Rahman A. H, Iffat Ara Gulshana M (2014) Taxonomy and Medicinal Uses on Amaranthaceae Family of Rajshahi, Bangladesh. Applied Ecology and Environmental Sciences, 2(2): 54-59.
  • Robertson KR (1981) The genera of Amaranthaceae in the southeastern United States. J. Arnold Arbor. 62: 267-314.
  • Sánchez del-Pino I, Borsch T, Motley TJ (2009) trnL-F and rpl16 sequence data and dense taxon sampling reveal monophyly of unilocular anthered Gomphrenoideae (Amaranthaceae) and an improved picture of their internal relationships. Systematic Botany, 34:57–67.doi: http://dx.doi.org/10.1600/036364409787602401
  • Standley PC (1915) The North American tribes and genera of Amaranthaceae. J. Wash. Acad. Sci. 5: 391-396.
  • Standley PC (1917) Amaranthaceae. In: N. L. Britton et al., eds. 1905+. North American Flora. New York. Vol. 21, pp. 95-169.
  • Sukhorukov AP (2007) Fruit anatomy and its taxonomic significance in Corispermum (Corispermoideae, Chenopodiaceae). Willdenowia, 37:63-87
  • USDA (2014) Classification for Kingdom Plantae Down to Family Solanaceae. United States Department of Agriculture, Natural Resources Conservation Service. Available at: https://plants.usda.gov/java/ClassificationServlet?source=profile&symbol=Solanaceae&display=63 [Accessed on 28th June, 2014]




Basu, S., Zandi, P., Sengupta, R., & Cetzal-Ix, W. (2014). Amaranthaceae: The pigweed family. Retrieved from http://www.eoearth.org/view/article/53cd605e0cf265cce6f20c95


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