Amaranthus L.
  • Sp. Pl. 2: 989. 1753. (1 May 1753)
  • Amaranth, pigweed [Greek amarantos, unfading, nonwithering]


Cite taxon page as 'WFO (2020): Amaranthus L. Published on the Internet;http://www.worldfloraonline.org/taxon/wfo-4000001466. Accessed on: 18 Feb 2020'

General Information

Herbs annual. Stem erect or decumbent. Leaves alternate, petiolate, margin entire. Flowers unisexual, on same plant or not, sessile, clustered at axils and at apex, in solitary or complex thyrsoid structures; each flower with 1 bract and 2 bracteoles, scarious. Tepals 5, rarely 1-4, erect or obliquely spreading, sometimes indurate at base after anthesis, green, equal or subequal, membranous. Stamens 5, rarely 1-4; filaments free, filiform, pseudostaminodes absent; anthers 2-loculed. Ovary with 1 erect ovule; style short or absent; stigmas 2 or 3, persistent, subulate or linear. Utricles globose or ovoid, laterally compressed, membranous, dehiscent by lid, dehiscing irregularly or falling off together with perianth and indehiscent. Seeds black or brown, globose or lenticular, without aril.

  • Provided by: [F].Flora Of CHina @ efloras.org
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    AMARANTHUS L.

    Hierbas anuales, a veces perennes, tallos solitarios, postrados, ascendentes o erectos, tallo y ramas glabros o escasamente pubescentes hacia arriba, con tricomas multicelulares cortos y simples; plantas monoicas o dioicas. Hojas alternas, más o menos decurrentes sobre el pecíolo, glabras o escasamente pubescentes en los nervios, con tricomas simples y cortos, nervio principal cortamente excurrente y formando una pequeña espina en el ápice; pecioladas. Inflorescencias compuestas muy complejas, la parte superior espiciforme y compacta con cimas densamente agregadas, la parte inferior no condensada con cimas distantes y hojas caulinares subyacentes, a veces toda la inflorescencia laxa, flores en inflorescencias cimosas parciales, las cimas con varios órdenes de ramificación, más o menos completas o el número de ramitas reducido y las partes modificadas a estructuras monoaxiales, brácteas y bractéolas subyacentes a las flores estaminadas y pistiladas similares, brácteas lanceoladas, triangulares u ovadas y glabras, bractéolas más cortas a más largas que las flores, lanceoladas u ovadas, glabras, cresta ausente, flores pistiladas o estaminadas a veces con rudimentos estériles, generalmente sin órganos reducidos del sexo opuesto, en las especies monoicas el número de flores pistiladas es mucho más alto; flores estaminadas con 3 ó 5 tépalos, lanceolados o angostamente ovados, iguales o desiguales, libres en la base, membranáceos, no endureciendo en la base, glabros, 1-nervios, estambres 3 ó 5, en igual número que tépalos en Nicaragua, filamentos filiformes, libres hasta la base, sin lobos, anteras biloculares, pseudoestaminodios ausentes; flores pistiladas con 3 ó 5 tépalos, ovados, oblongos, ligulados, obovados o espatulados, iguales o subiguales, a veces desiguales, más anchos en el medio o cerca del ápice, mucronados, obtusos, redondeados o emarginados en el ápice, libres o algo connados en la base, membranáceos o escariosos, a veces endurecidos en la base, glabros, 1-nervios y frecuentemente con nervios laterales, ligeramente más cortos a más largos que los utrículos maduros, ovario 1-ovulado, estilo muy corto y frecuentemente indefinido, estigma formando 2 ó 3 ramas filiformes frecuentemente engrosadas basalmente. Fruto un utrículo subgloboso u ovoide, escarioso, a veces casi membranáceo, liso o rugoso, circuncísil, irregularmente dehiscente o indehiscente; semilla subglobosa o lenticular, lisa o finamente reticulada, arilo ausente; flores permaneciendo en la planta en la madurez.

    Este género comprende ca 60 especies y es nativo de las regiones tropicales y subtropicales del Nuevo y Viejo Mundo, varias especies se han convertido en malezas pantropicales y han sido introducidas a las regiones templadas de ambos hemisferios; 5 especies se encuentran en Nicaragua, una de éstas con 1 subespecie silvestre y otra cultivada. Varios miembros del género se cultivan para la alimentación o como plantas ornamentales. "Bledo".

    J.D. Sauer. The grain Amaranths and their relatives: A revised taxonomic and geographic survey. Ann. Missouri Bot. Gard. 54: 103–137. 1967; M.P. Coons. Relationships of Amaranthus caudatus. Econ. Bot. 36: 129–146. 1982.

  • Provided by: [H].Flora de Nicaragua
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    Herbs, usually annual, rarely perennial, monoecious (subg. Amaranthus and Albersia) or dioecious (subg. Acnida), glabrous or pubescent. Stems erect, ascending, decumbent, or prostrate, usually branched, occasionally simple or nearly so; without nodal spines (except in A. spinosus ). Leaves alternate, petiolate; blade rhombic-ovate, ovate, obovate, spatulate, lanceolate, oblanceolate, or orbiculate to linear, base rounded to narrowly cuneate, margins usually entire, usually plane, slightly undulate, or crispate, rarely undulate-erose, apex acute, obtuse, or emarginate, usually mucronulate. Inflorescences terminal and/or axillary or exclusively terminal, compound dichasia arranged in spikes, thyrses, panicles, or glomerules; components of terminal inflorescences often subtended by reduced leaves (pseudobracts), each dichasium unit subtended by persistent bracts. Bracts ovate, lanceolate, linear, subulate, deltate, or broadly triangular (in A. acanthochiton), or proximal bracts modified into spines (in A. spinosus); bracts of pistillate flowers not keeled (keeled in A. scleropoides and A. crassipes); bracteoles absent or 1-2. Flowers unisexual. Pistillate flowers: tepals absent or (1-)3-5, distinct (connate in proximal 1/3 in A. polygonoides, equal or outer tepals larger than inner ones, usually membranaceous, sometimes scarious at maturity; stamens absent [rudimentary]; pistil 1; ovule 1; style 0.1-1 mm, or absent; stigmas 2-3(-5), slender. Staminate flowers: tepals 3-5, equal or subequal; stamens 3-5, filaments distinct, anthers 4-locular, pseudostaminodes absent; pistils absent or rudimentary. Utricles loosely enclosed by inner tepals, occasionally conspicuously 3(-5)-veined, usually globose, ovoid, or elongate-ovoid, thin walled, membranaceous, rugose or tuberculate, glabrous, dehiscence regularly circumscissile, irregularly dehiscent, or indehiscent. Seeds 1, subglobose or lenticular, usually smooth, shiny, sometimes indistinctly puncticulate or reticulate; embryo annular. x = 16, 17.

  • Provided by: [I].Flora of North America @ efloras.org
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    Flowers monoecious, dioecious or polygamous, sessile or subsessile, unibracteate and bibracteolate. Sepals 3-5, rarely 1, discrete, hypogynous, concave, occasionally basally clawed, equal or subequal, membranaceous, erect and persistent in fruit. Stamens 3-5, rarely 1, hypogynous, discrete; filaments filiform; anthers 4-locellate, introrse, medially attached, oblong. Ovary ovoid to lenticular, 1-locular, 1- ovulate, the ovule campylotropous on a short exarillate funicle, the placentation basal; styles 1-3; stigmata 2-3, usually exceeding the styles. Fruit a utricle, indehiscent or circumscissile; seeds cochleate-orbiculate, smooth to minutely verrucose. Leaves alternate, entire to minutely crenulate, long-petiolate. Erect or prostrate, glabrous to pubescent annual herbs. Inflorescences of terminal and/or axillary spicate or paniculate thyrses, in Panama monoecious or polygamous with female flowers basally, hermaphroditic flowers medially, and male flowers distally, the latter tending to have longer, narrower sepals.

  • Provided by: [E].Flora de Panama
  • "Monoecious or dioecious; fls small, each subtended by bracts and bracteoles; cal of 1–5 scarious or membranous sep separate to the base, often aristate, or wanting from the pistillate fls; stamens 1–5, with short filament and linear-oblong anther; ovary short and broad, compressed; style short or virtually none; stigmas (2)3(5), slender, pubescent; ovule l; fr a thin-walled to coriaceous utricle, indehiscent or bursting irregularly, or commonly circumscissile at the middle, crowned by the persistent stigmas; seed flattened or lenticular, round to obovate; prostrate to erect annuals, usually much branched, with alternate, petiolate, entire or sinuate lvs; fls in small axillary clusters, or aggregated into axillary or terminal, simple or panicled spike-like thyrses. 50, widespread. (Acnida) Spp. 8–13 are ± connected by intermediates of hybrid origin."

  • Provided by: [D].New York Botanical Garden
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    Morphology

    Annual or more rarely perennial herbs, glabrous or furnished with short and gland-like or multicellular hairs.

  • Provided by: [G].Plants Of the World Online Portal - FZ
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    Leaves alternate, long-petiolate, simple and entire or sinuate.

  • Provided by: [G].Plants Of the World Online Portal - FZ
    • Source: [
    • 8
    • ]. 

    Inflorescence basically cymose, bracteate, consisting entirely of dense to lax axillary clusters or the upper clusters leafless and more or less approximate to form a lax or dense “spike” or panicle.

  • Provided by: [G].Plants Of the World Online Portal - FZ
    • Source: [
    • 8
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    Flowers monoecious or (not in Africa) dioecious, bibracteolate.

  • Provided by: [G].Plants Of the World Online Portal - FZ
    • Source: [
    • 8
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    Perianth segments (2) 3–5, free or connate at the base, membranous, those of the female flowers sometimes slightly accrescent in fruit.

  • Provided by: [G].Plants Of the World Online Portal - FZ
    • Source: [
    • 8
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    Seeds usually black and shining, testa thin; embryo annular, endosperm present.

  • Provided by: [G].Plants Of the World Online Portal - FZ
    • Source: [
    • 8
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    Stigmas 2–3.

  • Provided by: [G].Plants Of the World Online Portal - FZ
    • Source: [
    • 8
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    Stamens free, usually similar in number to the perianth segments; anthers bilocular.

  • Provided by: [G].Plants Of the World Online Portal - FZ
    • Source: [
    • 8
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    Fruit a dry capsule, indehiscent, irregularly rupturing or commonly dehiscing by a circumcissile lid.

  • Provided by: [G].Plants Of the World Online Portal - FZ
    • Source: [
    • 8
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    Ovule solitary, erect.

  • Provided by: [G].Plants Of the World Online Portal - FZ
    • Source: [
    • 8
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    Leaves alternate, long-petiolate, simple and entire or sinuate

  • Provided by: [C].Plants Of the World Online Portal - FTEA
    • Source: [
    • 9
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    Annual or more rarely perennial herbs, glabrous or furnished with short and gland-like or multicellular hairs, dioecious (not in E. Africa) or monoecious

  • Provided by: [C].Plants Of the World Online Portal - FTEA
    • Source: [
    • 9
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    Seeds usually black and shining; testa thin; embryo annular, endosperm present.

  • Provided by: [C].Plants Of the World Online Portal - FTEA
    • Source: [
    • 9
    • ]. 

    Stigmas 2–3; ovule solitary, erect

  • Provided by: [C].Plants Of the World Online Portal - FTEA
    • Source: [
    • 9
    • ]. 

    Fruit a dry capsule, indehiscent, irregularly rupturing or commonly dehiscing by a circumscissile lid

  • Provided by: [C].Plants Of the World Online Portal - FTEA
    • Source: [
    • 9
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    Flowers bibracteolate; perianth-segments (2–)3–5, free or connate at the base, membranous, those of ♀ slightly accrescent in fruit

  • Provided by: [C].Plants Of the World Online Portal - FTEA
    • Source: [
    • 9
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    Stamens free, usually similar in number to the perianth-segments; anthers bilocular

  • Provided by: [C].Plants Of the World Online Portal - FTEA
    • Source: [
    • 9
    • ]. 

    Inflorescence basically cymose, bracteate, consisting entirely of dense to lax axillary clusters or the upper clusters leafless and ± approximate to form a lax or dense “spike” or panicle

  • Provided by: [C].Plants Of the World Online Portal - FTEA
    • Source: [
    • 9
    • ]. 

    Distribution

    Widespread in both temperate and tropical regions throughout the world, Amaranthus consists of perhaps fifty species. Many of them are inhabitants of open disturbed areas where they may become rather annoying weeds.

  • Provided by: [E].Flora de Panama
  • Literature

    SELECTED REFERENCES

    Brenner, D. M. et al. 2000. Genetic resources and breeding of Amaranthus. Pl. Breed. Rev. 19: 227-285. Costea, M. and D. A. DeMason. 2001. Stem morphology and anatomy in Amaranthus L. (Amaranthaceae): Taxonomic significance. J. Torrey Bot. Soc. 128: 254-281. Costea, M., A. Sanders, and G. Waines. 2001. Preliminary results toward a revision of the Amaranthus hybridus species complex (Amaranthaceae). Sida 19: 931-974. Costea, M., A. Sanders, and G. Waines. 2001b. Notes on some little known Amaranthus taxa (Amaranthaceae) in the United States. Sida 19: 975-992. Henrickson, J. 1999. Studies in New World Amaranthus (Amaranthaceae). Sida 18: 783-807. Mosyakin, S. L. and K. R. Robertson. 1996. New infrageneric taxa and combinations in Amaranthus L. (Amaranthaceae). Ann. Bot. Fenn. 33: 275-281. Sauer, J. D. 1955. Revision of the dioecious amaranths. Madroño 13: 5-46. Sauer, J. D. 1967b. The grain amaranths and their relatives: A revised taxonomic and geographic survey. Ann. Missouri Bot. Gard. 54: 103-137. Sauer, J. D. 1972b. The dioecious amaranths: A new species name and major range extensions. Madroño 21: 426-434. Uline, E. B. and W. L. Bray. 1894. A preliminary synopsis of the North American species of Amaranthus. Bot. Gaz. 19: 267-273, 313-320.

  • Provided by: [I].Flora of North America @ efloras.org
    • Source: [
    • 13
    • ]. 

    Included Species

    Synonyms

    Other Local Names

    NameLanguageCountry
    Amaranth, pigweed [Greek amarantos, unfading, nonwithering]

     Information From

    Amaranthaceae
    World Flora Online Data. 2017.
    • A CC0 1.0 Universal (CC0 1.0).
    MBG Floras Images
    http://www.tropicos.org/ImageSearch.aspx
    Flora images. Missouri Botanical Garden. Accessed on Jun. 2018.
    • B Missouri Botanical Garden
    Plants Of the World Online Portal - FTEA
    https://www.kew.org/science/who-we-are-and-what-we-do/strategic-outputs-2020/plants-of-the-world-online
    http://www.plantsoftheworldonline.org/terms-and-conditions
    • C
    New York Botanical Garden
    Descriptions of plants should be attributed to the full citation for each individual article, chapter or book that is the source for each record, which should include the authors of original publication.
    • D Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
    Flora de Panama
    http://www.tropicos.org/Project/PAC
    Robert E. Woodson, Jr. and Robert W. Schery Annals of the Missouri Botanical Garden Vol. 67, No. 4 (1980), pp. ii-xxxiii
    • E Missouri Botanical Garden
    Flora Of CHina @ efloras.org
    http://www.efloras.org/flora_page.aspx?flora_id=2
    'Flora of China @ eFloras (2008). Published on the Internet http://www.efloras.org/flora_page.aspx?flora_id=2 [accessed August 2016]' Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
    • F Missouri Botanical Garden
    Plants Of the World Online Portal - FZ
    https://www.kew.org/science/who-we-are-and-what-we-do/strategic-outputs-2020/plants-of-the-world-online
    http://www.plantsoftheworldonline.org/terms-and-conditions
    • G
    Flora de Nicaragua
    http://www.tropicos.org/projectwebportal.aspx?projectid=7&pagename=Home&langid=66
    WD Stevens, CU Ulloa, A Pool and OM Montiel. Missouri Botanical Garden Press, 2001
    • H Missouri Botanical Garden
    Flora of North America @ efloras.org
    http://www.efloras.org/flora_page.aspx?flora_id=1
    'Flora of North America @ eFloras (2008). Published on the Internet http://www.efloras.org/flora_page.aspx?flora_id=1 [accessed August 2016]' Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
    • I Flora of North America Association
    World Flora Online consortium
    http://www.worldfloraonline.org/organisation/WFO
    World Flora Online Data. 2018.
    • J CC0 1.0 Universal (CC0 1.0).