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Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Amaranthus tuberculatus
(rough-fruited water-hemp)

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Datasheet

Amaranthus tuberculatus (rough-fruited water-hemp)

Summary

  • Last modified
  • 06 November 2018
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • Amaranthus tuberculatus
  • Preferred Common Name
  • rough-fruited water-hemp
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Dicotyledonae
  • Summary of Invasiveness
  • Amaranthus tuberculatus is an annual dioecious herb 1-2 m tall which has spread from its native range in northern North America and is considered a major weed of agricultural fields and other disturbed areas in...

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Pictures

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PictureTitleCaptionCopyright
Amaranthus tuberculatus (rough-fruited water-hemp); habit, invasive in corn (maize) crops. Stradella, Pavia province, Lombardia region, Northern Italy. September, 2013.
TitleHabit
CaptionAmaranthus tuberculatus (rough-fruited water-hemp); habit, invasive in corn (maize) crops. Stradella, Pavia province, Lombardia region, Northern Italy. September, 2013.
Copyright©Duilio Iamonico-2013/Consultant, Rome, Italy
Amaranthus tuberculatus (rough-fruited water-hemp); habit, invasive in corn (maize) crops. Stradella, Pavia province, Lombardia region, Northern Italy. September, 2013.
HabitAmaranthus tuberculatus (rough-fruited water-hemp); habit, invasive in corn (maize) crops. Stradella, Pavia province, Lombardia region, Northern Italy. September, 2013.©Duilio Iamonico-2013/Consultant, Rome, Italy
Amaranthus tuberculatus (rough-fruited water-hemp); synflorescence. Stradella, Pavia province, Lombardia region, Northern Italy. September, 2013.
TitleSynflorescence
CaptionAmaranthus tuberculatus (rough-fruited water-hemp); synflorescence. Stradella, Pavia province, Lombardia region, Northern Italy. September, 2013.
Copyright©Duilio Iamonico-2013/Consultant, Rome, Italy
Amaranthus tuberculatus (rough-fruited water-hemp); synflorescence. Stradella, Pavia province, Lombardia region, Northern Italy. September, 2013.
SynflorescenceAmaranthus tuberculatus (rough-fruited water-hemp); synflorescence. Stradella, Pavia province, Lombardia region, Northern Italy. September, 2013.©Duilio Iamonico-2013/Consultant, Rome, Italy
Amaranthus tuberculatus (rough-fruited water-hemp); habit, growing in the riparian zone of a man-made pond. Lewisville Aquatic Ecosystem Research Facility, Lewisville, Texas, USA. Spring, 2004.
TitleHabit
CaptionAmaranthus tuberculatus (rough-fruited water-hemp); habit, growing in the riparian zone of a man-made pond. Lewisville Aquatic Ecosystem Research Facility, Lewisville, Texas, USA. Spring, 2004.
Copyright©Robin R. Buckallew/hosted by the USDA-NRCS PLANTS Database - All Rights Reserved
Amaranthus tuberculatus (rough-fruited water-hemp); habit, growing in the riparian zone of a man-made pond. Lewisville Aquatic Ecosystem Research Facility, Lewisville, Texas, USA. Spring, 2004.
HabitAmaranthus tuberculatus (rough-fruited water-hemp); habit, growing in the riparian zone of a man-made pond. Lewisville Aquatic Ecosystem Research Facility, Lewisville, Texas, USA. Spring, 2004.©Robin R. Buckallew/hosted by the USDA-NRCS PLANTS Database - All Rights Reserved
Amaranthus tuberculatus (rough-fruited water-hemp); habit, on roadside. East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.
TitleHabit
CaptionAmaranthus tuberculatus (rough-fruited water-hemp); habit, on roadside. East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.
Copyright©Zoya Akulova-2014/CalPhotos - CC BY-NC 3.0
Amaranthus tuberculatus (rough-fruited water-hemp); habit, on roadside. East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.
HabitAmaranthus tuberculatus (rough-fruited water-hemp); habit, on roadside. East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.©Zoya Akulova-2014/CalPhotos - CC BY-NC 3.0
Amaranthus tuberculatus (rough-fruited water-hemp); habit. This plant is approx. 68cm (27") in height.
TitleHabit
CaptionAmaranthus tuberculatus (rough-fruited water-hemp); habit. This plant is approx. 68cm (27") in height.
Copyright©Bruce Ackley/The Ohio State University/Bugwood.org - CC BY 3.0 US
Amaranthus tuberculatus (rough-fruited water-hemp); habit. This plant is approx. 68cm (27") in height.
HabitAmaranthus tuberculatus (rough-fruited water-hemp); habit. This plant is approx. 68cm (27") in height.©Bruce Ackley/The Ohio State University/Bugwood.org - CC BY 3.0 US
Amaranthus tuberculatus (rough-fruited water-hemp); flowers.  East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.
TitleFlowers
CaptionAmaranthus tuberculatus (rough-fruited water-hemp); flowers. East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.
Copyright©Zoya Akulova-2014/CalPhotos - CC BY-NC 3.0
Amaranthus tuberculatus (rough-fruited water-hemp); flowers.  East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.
FlowersAmaranthus tuberculatus (rough-fruited water-hemp); flowers. East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.©Zoya Akulova-2014/CalPhotos - CC BY-NC 3.0
Amaranthus tuberculatus (rough-fruited water-hemp); flowers. East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.
TitleFlowers
CaptionAmaranthus tuberculatus (rough-fruited water-hemp); flowers. East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.
Copyright©Zoya Akulova-2014/CalPhotos - CC BY-NC 3.0
Amaranthus tuberculatus (rough-fruited water-hemp); flowers. East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.
FlowersAmaranthus tuberculatus (rough-fruited water-hemp); flowers. East of Stockton, by Highway 4, San Joaquin County, California, USA. August, 2014.©Zoya Akulova-2014/CalPhotos - CC BY-NC 3.0
Amaranthus tuberculatus (rough-fruited water-hemp); seedling, lab specimen.
TitleSeedling
CaptionAmaranthus tuberculatus (rough-fruited water-hemp); seedling, lab specimen.
Copyright©Bruce Ackley/The Ohio State University/Bugwood.org - CC BY 3.0 US
Amaranthus tuberculatus (rough-fruited water-hemp); seedling, lab specimen.
SeedlingAmaranthus tuberculatus (rough-fruited water-hemp); seedling, lab specimen.©Bruce Ackley/The Ohio State University/Bugwood.org - CC BY 3.0 US

Identity

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Preferred Scientific Name

  • Amaranthus tuberculatus (Moq.) Sauer

Preferred Common Name

  • rough-fruited water-hemp

Other Scientific Names

  • Acnida tamariscina var. tuberculata (Moq.) Uline & Bray
  • Acnida tuberculata Moq.
  • Amaranthus rudis J.D. Sauer
  • Amaranthus tuberculatus var. rudis Costea & Tardif

International Common Names

  • English: common waterhemp; common water-hemp; roughfruit amaranth; rough-fruit amaranth; tall waterhemp; tall water-hemp
  • French: amaranth rugueuse

Local Common Names

  • Israel: yarbuz ha’gadot
  • Italy: amaranto tubercolato

Summary of Invasiveness

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Amaranthus tuberculatus is an annual dioecious herb 1-2 m tall which has spread from its native range in northern North America and is considered a major weed of agricultural fields and other disturbed areas in 40 US states. In the mid-western USA it has become increasingly difficult to control over the past 10 years due to a persistent seedbank and the development of resistance to certain herbicides. A. tuberculatus seed is a known contaminant of soyabean seed and other grains, and has been accidentally introduced and become naturalized in parts of West Asia and Europe. Potential spread to other areas should be considered likely.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Dicotyledonae
  •                     Order: Caryophyllales
  •                         Family: Amaranthaceae
  •                             Genus: Amaranthus
  •                                 Species: Amaranthus tuberculatus

Notes on Taxonomy and Nomenclature

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Originally described by Moquin-Tandon (1849) as Acnida tuberculata on the basis of plants cultivated at the Botanical Garden in Geneva (G), Switzerland (“v.v. in hort. Genev.” as reported in the protologue), the lectotype of Amaranthus tuberculatus was only designated in 2015 by Iamonico (2015b) on a specimen preserved at G. The Moquin-Tandon species name was rarely used by subsequent authors. In the 1970s, Sauer (1972) provided the first revision of the dioecious amaranths, and also described the new species Amaranthus rudis, which differed from A. tuberculatus on the basis of some morphological traits, including plant height, tepal number and fruit dehiscence/indehiscence. A more recent study by Pratt and Clark (2001) showed a continuum in the variability of these characters, which led the authors to synonymize the names A. rudis and A. tuberculatus, the latter having nomenclatural priority. Two years later, Costea and Tardif (2003b) proposed varietal rank for A. rudis. Currently, the opinion of Pratt and Clark (2001) is generally accepted (see, for example, Mosyakin and Robertson, 2003; The Plant List, 2013; Iamonico 2015a, 2015c). On the basis of the classification by Mosyakin and Robertson (1996 ), A. tuberculatus belongs to the subgenus Acnida (L.) Aellen ex K.R. Robertson, section Acnida.

Description

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A. tuberculatus is an herb (0.5-)1-2(-3) m tall, dioecious, annual (therophyte). Stems erect or ascending, glabrous, often reddish, branched (rarely simple). Leaves green to reddish, ovate to lanceolate-linear (1.5-)2.0-12.0(-15.0) × (0.5-)0.8-2.5(-3.0) cm, with entire margins, apex obtuse or retuse, mucronulate, base cuneate, glabrous, petioled (petiole 0.5-5.0 cm long). Synflorescences terminal, spike- or panicle-like type (sometimes interrupted-moniliform), erect, usually reddish, the main florescence up to 50 cm long. Floral bracts 1, green to reddish, lanceolate ((0.5-)0.8-2.5(-2.8) × 0.4-1.1(-1.9) mm), as long as or slightly longer than the perianth, sometimes carinate, apex acuminate, margin entire, glabrous. Staminate flowers with 5 tepals, ovate to lanceolate ((1.7-)1.8-3.0(-3.5) × 0.5-1.1(-1.4) mm), apex obtuse or acute, awned (especially the inner tepals); stamens 5. Pistillate flowers without tepals or with only one reduced lanceolate to linear tepal (up to 1.5 mm long); style branches ± erect, stigmas 3. Fruit dark-brown to reddish, subglobose or ellipsoidal ((0.9-)1.2-1.9(-2.3) × 0.9-1.5 mm), as long as or slightly shorter than the perianth, usually smooth, dehiscent. Seed lenticular (0.6-1.0(-1.2) mm in diameter), black or reddish-brown (see Mosyakin and Robertson, 2003) .

Distribution

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It is widely believed that A. tuberculatus is native to northern North America, north of Missouri and Tennessee to the Great Lakes area of the USA and Canada, while the synonymous A. rudis was probably originally native to the Great Plains west of the Mississippi, from Texas to Iowa (Flora of North America Editorial Committee, 2015). The exact native range, however, is unknown with the current state of knowledge, and further studies are needed to clarify this. Indeed, the species is considered as alien in numerous parts of the USA and Canada, although different authorities differ as to which states and provinces the species is native to and into which it has been introduced. A. tuberculatus can definitely be considered as an alien species out of North America; it is currently naturalized and/or invasive in parts of West Asia (Israel and Jordan) and Europe.

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

IsraelPresentIntroducedDanin, 2015; Iamonico, 2015
JordanPresent, few occurrencesIntroducedCastri et al., 1990

North America

CanadaPresentPresent based on regional distribution.
-British ColumbiaPresentIntroducedCostea et al., 2005
-ManitobaPresentIntroducedMosyakin and Robertson, 2003
-OntarioPresentNative Invasive Oldham, 2010; Bradley, 2013
-Prince Edward IslandPresentIntroducedMosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-QuebecPresentNativeMosyakin and Robertson, 2003
USAWidespreadNative Invasive Flora of North America Editorial Committee, 2015
-AlabamaPresentIntroducedMosyakin and Robertson, 2003
-ArkansasPresentIntroducedMosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-CaliforniaPresentIntroducedHrusa et al., 2002; Mosyakin and Robertson, 2003; Jepson eFlora, 2015
-ColoradoPresentIntroducedMosyakin and Robertson, 2003; Snow and Brasher, 2004
-ConnecticutPresentIntroducedMosyakin and Robertson, 2003; Go Botany, 2015; USDA-ARS, 2015Native according to USDA-ARS, 2015
-DelawarePresentIntroducedMosyakin and Robertson, 2003; Flora of Delaware, 2015; USDA-ARS, 2015Native according to USDA-ARS, 2015
-GeorgiaPresentIntroducedMosyakin and Robertson, 2003
-IdahoPresentIntroducedMosyakin and Robertson, 2003
-IllinoisPresentIntroduced Invasive Mosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-IndianaPresentIntroduced Invasive Mosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-IowaPresentNative Invasive Mosyakin and Robertson, 2003; USDA-ARS, 2015
-KansasPresentNative Invasive Mosyakin and Robertson, 2003; USDA-ARS, 2015
-KentuckyPresentIntroduced Invasive Mosyakin and Robertson, 2003; Jones, 2005; USDA-ARS, 2015Native according to USDA-ARS, 2015
-LouisianaPresentIntroducedMosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-MainePresentIntroducedMosyakin and Robertson, 2003; Go Botany, 2015; USDA-ARS, 2015Native according to USDA-ARS, 2015
-MarylandPresentIntroducedMosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-MassachusettsPresentIntroducedMosyakin and Robertson, 2003; Cullina et al., 2011; Go Botany, 2015; USDA-ARS, 2015Native according to USDA-ARS, 2015
-MichiganPresentIntroducedMosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-MinnesotaPresentIntroducedMosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-MississippiPresentIntroduced Invasive Mosyakin and Robertson, 2003
-MissouriPresentNative Invasive Mosyakin and Robertson, 2003; USDA-ARS, 2015
-MontanaPresentIntroducedMincemoyer, 2013
-NebraskaPresentIntroduced Invasive Mosyakin and Robertson, 2003; Sarangi et al., 2015; USDA-ARS, 2015Native according to USDA-ARS, 2015
-NevadaPresentIntroduced Not invasive Mosyakin and Robertson, 2003
-New HampshirePresentIntroducedMosyakin and Robertson, 2003; Go Botany, 2015; USDA-ARS, 2015Native according to USDA-ARS, 2015
-New JerseyPresentIntroducedAnderson, 2009; Ferren Jr, 2011; USDA-ARS, 2015Native according to USDA-ARS, 2015
-New MexicoPresentIntroducedMosyakin and Robertson, 2003
-New YorkPresentNativeMosyakin and Robertson, 2003; USDA-ARS, 2015
-North CarolinaPresentIntroducedMosyakin and Robertson, 2003
-North DakotaPresentIntroducedMosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-OhioPresentIntroduced Invasive Cooperrider et al., 2001; Mosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-OklahomaPresentIntroduced Invasive Buthold, 2013; USDA-ARS, 2015Native according to USDA-ARS, 2015
-PennsylvaniaPresentIntroducedMosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-South CarolinaPresentIntroducedMosyakin and Robertson, 2003
-South DakotaPresentIntroducedMosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-TennesseePresentIntroducedMosyakin and Robertson, 2003; Chester et al., 2009; University of Tennessee Herbarium, 2015; USDA-ARS, 2015Native according to USDA-ARS, 2015
-TexasPresentIntroducedMosyakin and Robertson, 2003; Hannick et al., 2013; USDA-ARS, 2015Native according to USDA-ARS, 2015
-VermontLocalisedNativeMosyakin and Robertson, 2003; Go Botany, 2015
-VirginiaPresentIntroducedVirginia Botanical Associates, 2015First recorded in Rockingham County in 2012
-WashingtonPresentIntroducedMosyakin and Robertson, 2003; Burke Museum of Natural History and Culture, 2015
-West VirginiaPresentIntroducedMosyakin and Robertson, 2003; USDA-ARS, 2015Native according to USDA-ARS, 2015
-WisconsinPresentNativeMosyakin and Robertson, 2003; Flora of Wisconsin, 2015; USDA-ARS, 2015

Europe

AustriaPresentIntroducedIamonico, 2015
BelgiumPresentIntroduced Not invasive Iamonico, 2015
Czech RepublicPresentIntroducedIamonico, 2015
DenmarkPresentIntroduced Not invasive Iamonico, 2015
FinlandPresentIntroducedIamonico, 2015
GermanyLocalisedIntroducedSchmitz, 2002; Iamonico, 2015
ItalyPresentIntroduced Invasive Iamonico, 2015
NetherlandsLocalisedIntroduced Not invasive Meijden et al., 2003
RomaniaLocalisedIntroduced Not invasive Iamonico, 2015
Russian FederationPresentIntroducedIamonico, 2015
SpainLocalisedIntroducedSanchez and Verloove, 2013Observed at Nuevo Puerto, Palos de la Frontera, Huelva
SwedenPresentIntroducedIamonico, 2015
UKPresentIntroducedIamonico, 2015
UkraineLocalisedIntroduced Not invasive Iamonico, 2015

History of Introduction and Spread

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Data from microsatellite marker studies by Waselkov and Olsen (2014), which identified two genetic lineages for A. tuberculatus, suggested that an eastward movement of the western genetic lineage (identified by some as var. rudis) is the source of the agricultural invasion of water-hemp seen in the USA today. Spread of the weed has been facilitated by changing farming practices, such as the increased sowing of maize and soyabean monocultures and adoption of reduced or no-tillage systems. From the USA, the weed (var. rudis) has recently spread to Canada where it was found in soyabean crops in south-western Ontario in 2002 and 2003, although the var. tuberculatus form has been known in Ontario and Quebec from the end of the 19th century (Costea et al., 2005). Contamination of soyabean shipments has been a major means by which water-hemp has become established in Europe. In Belgium, for example, since 1983 A. tuberculatus has been found in port areas (Antwerp, Gent), near grain conveyors and mills, on quaysides and along roadside verges. Since 2003, it has spread along gravelly riverbanks in Belgium and the Netherlands (Manual of the Alien Plants of Belgium, 2015). Sanchez Gullon and Verloove (2013) report A. tuberculatus for the first time in Spain at the port in Palos de la Frontera.

Risk of Introduction

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Contaminated soyabean and other grain shipments remain a major risk factor in the invasion of new areas by A. tuberculatus. In Europe, first reports tend to occur in the vicinity of ports. Once introduced, it appears to thrive along water courses and rivers, its high reproductive capacity allowing it to spread rapidly with resulting adverse ecological effects on the native riparian herbaceous vegetation, for example along the banks of the River Po in Italy (Iamonico 2015c).

Habitat

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A. tuberculatus occurs naturally in North America on the margins of freshwater bodies, rivers, lakes, ponds, marshes and bogs, while preferred human-made habitats are roadsides, railroads, cultivated fields, waste land and gardens (Mosyakin and Robertson, 2003, Iamonico, 2015c).

Habitat List

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial
 
Terrestrial – ManagedCultivated / agricultural land Principal habitat Harmful (pest or invasive)
Cultivated / agricultural land Principal habitat Natural
Disturbed areas Principal habitat Harmful (pest or invasive)
Disturbed areas Principal habitat Natural
Rail / roadsides Secondary/tolerated habitat Harmful (pest or invasive)
Rail / roadsides Secondary/tolerated habitat Natural
Urban / peri-urban areas Secondary/tolerated habitat Harmful (pest or invasive)
Urban / peri-urban areas Secondary/tolerated habitat Natural
Terrestrial ‑ Natural / Semi-naturalRiverbanks Principal habitat Harmful (pest or invasive)
Riverbanks Principal habitat Natural
Wetlands Principal habitat Harmful (pest or invasive)
Wetlands Principal habitat Natural

Hosts/Species Affected

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A. tuberculatus negatively affects the growth and yield of cultivated crops. Estimated soyabean yield losses due to the presence of dense populations of A. tuberculatus (89-360 plants/m2) that emerged at the crop unifoliate stage have been high; for example, yield reductions of 43% in Illinois and 27-63% in Kansas have been reported (Hager et al., 2002; Bensch et al., 2003). In maize crops in Illinois, season-long interference from dense populations of A. tuberculatus (60-300 plants/m2) reduced yield by up to 74% (Steckel and Sprague, 2004).

Growth Stages

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Biology and Ecology

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Genetics

A. tuberculatus is a diploid taxon with a chromosome number of 2n = 32 (Trucco et al. 2006). The species can hybridize in the wild with other members of the subgenus Acnida and even with monoecious species belonging to subgenus Amaranthus, such as A. hybridus (Costea et al., 2005; Trucco et al., 2004, 2005).

Throughout the mid-western USA, A. tuberculatus populations have since the early 1990s developed genetic resistance to herbicides inhibiting photosystem II (e.g., triazines), acetolactate synthase (ALS) (e.g., sulfonylureas) and protoporphyrinogen oxidase (PPO) (e.g., diphenylethers) (Heap, 2004). The first report of resistance was to triazine herbicides in Nebraska in 1990 (Anderson et al., 1996), and has since then been discovered, along with resistance to other herbicides, in numerous US states as well as Ontario, Canada. Cases of multiple resistance to triazines, ALS or PPO inhibitors have also been reported (Heap, 2004; Patzoldt et al., 2005). Genetic variation within and between populations in response to various herbicides (Patzoldt et al., 2003), as well as interspecific hybridization and gene flow between species (Wetzel et al. 1999; Franssen et al. 2001b), have probably contributed to the rapid spread of herbicide resistance in Amaranthus species.

Reproductive Biology

A. tuberculatus is a summer annual herb (therophyte). Flower initiation depends on photoperiod. Under short-day conditions (8 hours) flowering starts after 14–16 days, while under long-day conditions (16 hours) it starts at about 45 days. Pollination is mediated by wind, the pollen having numerous and uniformly distributed apertures which generate a layer of turbulent air to decrease the friction between the pollen grain and the air, thus maximizing the distance pollen grains can be wind-dispersed (Franssen et al., 2001a, Costea et al., 2005). Each plant produces a high number of viable seeds. Seedlings emerge and grow rapidly.

Physiology and Phenology

A. tuberculatus, like all Amaranthus species, is a C4 photosynthetic pathway species, exhibiting the characteristic Kranz leaf anatomy and high photosynthetic rate at high temperatures and light intensities, with reduced photorespiration and a low CO2 compensation point compared to C3 species (Costea et al., 2004). Flowering time is from late May to August in its native distribution area, and can be from September to October in some non-native areas (e.g., in Europe).

Associations

In Canada, frequently associated plant species are Chenopodium album, A. retroflexus, A. powellii  and Polygonum persicaria [Persicaria maculosa], while in the USA (Iowa) in soyabean and maize crops not treated with herbicides, associated weed species include Ambrosia artemisiifolia, Asclepias syriaca, C. album, Erigeron sumatrensis [Conyza sumatrensis], Cyperus esculentus, Hibiscus trionum, Setaria faberi, S. glauca [Setaria pumila], Sida spinosa, Solanum carolinense, S. ptycanthum and Polygonum pensylvanicum [Persicaria pensylvanica] (Felix and Owen, 1999; Costea et al., 2005).

Environmental Requirements

Although a temperate species, A. tuberculatus occurs over a wide climate range. It can tolerate a broad range of soil types and textures, but prefers those that are well-drained and rich in nutrients. A soil pH from 4.5 to 8 is suitable. Plants can tolerate temporary flooding, but have no salinity tolerance. CaCO3 tolerance is said to be moderate (USDA-NRCS, 2015).

Climate

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ClimateStatusDescriptionRemark
Cf - Warm temperate climate, wet all year Tolerated Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year
Cs - Warm temperate climate with dry summer Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers
Ds - Continental climate with dry summer Preferred Continental climate with dry summer (Warm average temp. > 10°C, coldest month < 0°C, dry summers)

Latitude/Altitude Ranges

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Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
30-55

Air Temperature

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Parameter Lower limit Upper limit
Mean minimum temperature of coldest month (ºC) -3 0

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Albugo bliti Pathogen Leaves not specific
Amara aeneopolita Herbivore Seeds not specific
Anisodactylus rusticus Herbivore Seeds not specific
Cercospora acnidae Pathogen Leaves not specific
Gryllus pennsylvanicus Herbivore Seeds not specific N/A N/A
Harpalus pensylvanicus Herbivore Seeds not specific
Microsphaeropsis amaranthi Pathogen Leaves/Stems not specific Smith et al., 2006 USA
Phyllosticta amaranthi Pathogen Leaves not specific
Phymatotrichopsis omnivora Pathogen Roots not specific
Stenolophus comma Herbivore Seeds not specific N/A N/A

Notes on Natural Enemies

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In the USA (Iowa), the most important post-dispersal seed predators observed were Amara aeneopolita, Anisodactylus rusticus, Stenolophus comma, Gryllus pennsylvanicus and Harpalus pensylvanicus.

Fungi found infecting A. tuberculatus in the USA have included Albugo bliti [Wilsoniana bliti], Phymatotrichum omnivorum [Phymatotrichopsis omnivora], Cercospora acnidae and Phyllosticta amaranthi. Microsphaeropsis amaranthi has been tested as a possible biocontrol agent. There appear to be no data on bacteria, viruses or parasites (Costea et al., 2005).

Means of Movement and Dispersal

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Natural Dispersal

The morphology of the seeds facilitates dispersal by water, animals and birds, and to a lesser extent wind, with dispersal by water (streamlets produced on the soil by rain, surface irrigation and rivers) being of particular significance as both fruits and seeds float, and plants prefer to grow in the proximity of water (Costea et al., 2005).

Vector Transmission (Biotic)

Seeds of A. tuberculatus are also dispersed by animals and birds, although there is no evidence of ingestion and subsequent excretion by livestock (Costea et al., 2005).

Accidental Introduction

Anthropogenic factors such as farm machinery, and manure and compost spreading also aid dispersal of A. tuberculatus seed within and between fields, while transport of contaminated soyabean seed and other grains aids local and long-distance dispersal through accidental spillages (Costea et al., 2005; Manual of the Alien Plants of Belgium, 2015).

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
True seeds (inc. grain) Yes
Plant parts not known to carry the pest in trade/transport
Bulbs/Tubers/Corms/Rhizomes
Flowers/Inflorescences/Cones/Calyx
Fruits (inc. pods)
Growing medium accompanying plants
Leaves
Roots
Seedlings/Micropropagated plants
Stems (above ground)/Shoots/Trunks/Branches

Impact Summary

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CategoryImpact
Economic/livelihood Negative
Environment (generally) Negative
Human health Negative

Economic Impact

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A. tuberculatus successfully outcompetes cultivated plants both in its native range and where introduced and naturalized. By reducing crop yields by as much as 63% for soyabeans (Hager et al., 2002; Bensch et al., 2003) and 74% for maize (Steckel and Sprague, 2004), the weed can substantially reduce farm incomes. Inattention by farmers to the situation with A. tuberculatus in their fields, as with other Amaranthus species, can help the weed become more established and more troublesome (Costea et al., 2001a; Iamonico, 2010b).

Already a noxious weed, A. tuberculatus populations have since the 1990s been found exhibiting resistance to triazines and ALS- and PPO-inhibiting herbicides, as well as glyphosate, thus further impacting on crop yields and the costs of crop production, and requiring not only the development and use of other, newer herbicides, but also changes to weed management strategies and agricultural practices to reduce the risk of herbicide resistance development and spread (Tranel et al., 2011). 

Environmental Impact

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Increases in alien invasive weed population densities cause modifications in the structure of native vegetation communities by, for example, changing the frequency and coverage of native species (α-biodiversity) through high and positive competition for nutrients and space. A. tuberculatus can therefore be a threat to native riparian herbaceous vegetation, especially in territories outside its native range. In the River Po area of northern Italy, for example, the spread of alien species (Rossi et al., 2013), such as A. tuberculatus, threatens the endangered species Myricaria germanica (Alessandrini et al., 2013), Typha minima, Sagittaria sagittifolia and Hippuris vulgaris, and the near-threatened Typha shuttleworthii and Epipactis palustris, as well as Lindernia palustris (Iamonico, pers. obs., 2015).

Another potential unfavourable impact on biodiversity is the capacity of A. tuberculatus to hybridize with other Amaranthus species, thus negatively affecting the gene pools of those species.

Threatened Species

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Threatened SpeciesConservation StatusWhere ThreatenedMechanismReferencesNotes
Epipactis palustrisNT (IUCN red list: Near threatened) NT (IUCN red list: Near threatened)ItalyCompetition - monopolizing resources
Hippuris vulgarisNo DetailsItalyCompetition - monopolizing resources
Lindernia palustrisNo DetailsItalyCompetition - monopolizing resources
Myricaria germanicaEN (IUCN red list: Endangered) EN (IUCN red list: Endangered); No details No detailsItalyCompetition - monopolizing resources
Sagittaria sagittifoliaNo DetailsItalyCompetition - monopolizing resources
Typha minimaNo DetailsItalyCompetition - monopolizing resources
Typha shuttleworthiiNo DetailsItalyCompetition - monopolizing resources

Social Impact

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The high number of flowers and pollen grains produced by each plant, as well as the reduced sizes and types of pollen in the genus Amaranthus as a whole (Costea et al. 2001b, 2005; Costea and Tardif, 2003; Iamonico 2010), would indicate that A. tuberculatus is a potentially allergenic species.

Risk and Impact Factors

Top of page Invasiveness
  • Invasive in its native range
  • Proved invasive outside its native range
  • Has a broad native range
  • Abundant in its native range
  • Highly adaptable to different environments
  • Is a habitat generalist
  • Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
  • Pioneering in disturbed areas
  • Highly mobile locally
  • Benefits from human association (i.e. it is a human commensal)
  • Fast growing
  • Has high reproductive potential
  • Has high genetic variability
Impact outcomes
  • Changed gene pool/ selective loss of genotypes
  • Ecosystem change/ habitat alteration
  • Increases vulnerability to invasions
  • Modification of nutrient regime
  • Modification of successional patterns
  • Negatively impacts agriculture
  • Negatively impacts human health
  • Negatively impacts livelihoods
  • Reduced native biodiversity
  • Threat to/ loss of endangered species
  • Threat to/ loss of native species
  • Damages animal/plant products
Impact mechanisms
  • Causes allergic responses
  • Competition - monopolizing resources
  • Competition - shading
  • Hybridization
  • Rapid growth
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Difficult/costly to control

Uses

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There appear to be no significant human uses of A. tuberculatus from any economic, social or environmental point of view. As with other amaranths, A. tuberculatus has the potential of being used as a leaf vegetable.

Diagnosis

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No laboratory techniques appear to be available for testing and screening.

Detection and Inspection

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Although no specific research into detection methods appears to have been carried out for A. tuberculatus, detection can be carried out by careful and continuous floristic surveys during the seasons, especially around ports handling soyabean and grain shipments.

Similarities to Other Species/Conditions

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A. tamariscinus Nutt. is a similar and related species which was considered a synonym of A. tuberculatus by some authors. On the basis of an examination of Nuttall's collection, Sauer (1972) stated that the name A. tamariscinus refers to a sterile hybrid between A. tuberculatus and a monoecious taxon, possibly A. hybridus. Recently, Iamonico (2010a) clarified the identity of A. tamariscinus, confirming its hybrid origin. The two species differ by the number and length of the tepals: absent or sometimes a single tepal ≤ 1.5 mm long in A. tuberculatus, while A. tamariscinus has 2 tepals, one of them ≤ 1 mm long. 

With regard to the other weedy Amaranthus species present in North America, A. tuberculatus can be distinguished by its long, narrow leaves and by the lack of hairs on its stems and leaves, giving the plant a very glossy appearance (Gower and Lee, 2001).

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

It should be possible to reduce or manage the impact of A. tuberculatus invasions if quick action is taken to identify and map the foci of infestations, determine population dynamics under the prevailing climatic conditions and establish proper methods of control and management.

Cultural Control and Sanitary Measures

As the hypocotyl of A. tuberculatus can only elongate 0.5-3.5(-5) cm, most seedlings emerge from near the soil surface. This being the case, no-tillage or reduced-tillage cropping systems should be avoided, and deep mouldboard ploughing to bury seeds should be practised. Interrow cultivation can also reduce weed survival and seed return (Buhler et al., 2001). Thorough cleaning of combine harvesters before moving equipment to other fields would limit the transport of seeds (Costea et al., 2005).

Biological Control

Microsphaeropsis amaranthi infecting A. tuberculatus causes foliar and stem necrosis, resulting in plant mortality under optimal conditions. Preliminary testing in the Midwestern USA concluded that its efficacy as a bioherbicide, however, was limited under field conditions (Smith et al., 2006).

Chemical Control

Foliar-applied herbicides will control growing A. tuberculatus weeds. Tested pre-emergence herbicides include sulfentrazone (Krausz and Young, 2003), flumioxazin, S-metolachlor, pendimethalin, acetochlor, linuron, imazethapyr, metribuzin, flufenacet plus metribuzin, flumetsulam plus metolachlor, isoxaflutole and mesotrione (Sweat et al. 1998, Niekamp and Johnson 2001, Steckel et al. 2002). Post-emergence herbicides which have proved effective include lactofen and fomesafen (Hager et al. 2003).

Gaps in Knowledge/Research Needs

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Further research is required in the following areas:

Molecular taxonomical analyses of native and alien populations.

Phytosociological studies in the USA and non-native areas in which A. tuberculatus appears to be invasive.

Detailed study of the chorology of A. tuberculatus in its native and introduced ranges.

Investigations of its invasiveness through studies of the history of introduction (examination of herbaria specimens), substratum characteristics, pollination, pollen morphology, and seed production, dispersal and germination.

References

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Alessandrini A; Ardenghi NMG; Montagnani C; Selvaggi A; Varese P; Adorni M; Bovio M; Conti F; Foggi B; Ghillani L; Gubellini L; Magrini S; Michielon B; Peccenini S; Prosser F; Rossi G; Tasinazzo S; Vidali M; Villani MC; Wilhalm T, 2013. Myricaria germanica (L.) Desv. Informatore Botanico Italiano, 45(2):375-380.

Anderson DD; Roeth FW; Martin AR, 1996. Occurrence and control of triazine-resistant common waterhemp (Amaranthus rudis) in field corn (Zea mays). Weed Technology, 10(3):570-575.

Anderson K, 2009. A check list of the plants of New Jersey. 60 pp. http://www.cumauriceriver.org/botany/checklist2009.pdf

Bensch CN; Horak MJ; Peterson D, 2003. Interference of redroot pigweed (Amaranthus retroflexus), Palmer amaranth (A. palmeri), and common waterhemp (A. rudis) in soybean. Weed Science, 51(1):37-43.

Bradley DJ, 2013. Southern Ontario vascular plant species list, 3rd edition. Peterborough, Ontario, Canada: Ontario Ministry of Natural Resources, 78 pp.

Buhler DD; Kohler KA; Thompson RL, 2001. Weed seed bank dynamics during a five-year crop rotation. Weed Technology, 15(1):170-176.

Burke Museum of Natural History and Culture, 2015. Plants of Washington. Seattle, WA, USA: University of Washington. http://biology.burke.washington.edu/herbarium/imagecollection.php

Buthold AK, 2013. A checklist of the vascular flora of the Mary K. Oxley Nature Center, Tulsa County, Oklahoma. Oklahoma Native Plant Record, 13:29-47.

Chester EW; Wofford BE; Estes D; Bailey C, 2009. A fifth checklist of Tennessee vascular plants. Fort Worth, Texas, USA: Botanical Research Institute of Texas, 102 pp.

Cooperrider TS; Cusick AW; Kartesz JT, 2001. Seventh catalog of the vascular plants of Ohio. Columbus, OH, USA: Ohio State University Press, 256 pp.

Costea M; Sanders A; Waines G, 2001. Notes on some little known Amaranthus taxa (Amaranthaceae) in the United States. Sida, 19(4):975-992.

Costea M; Sanders A; Waines G, 2001. Preliminary results toward a revision of the Amaranthus hybridus species complex (Amaranthaceae). Sida, 19(4):931-974.

Costea M; Tardif FJ, 2003. Conspectus and notes on the genus Amaranthus in Canada. Rhodora, 105(923):260-281.

Costea M; Weaver SE; Tardif FJ, 2004. The biology of Canadian weeds. 130. Amaranthus retroflexus L., A. powellii S. Watson and A. hybridus L. Canadian Journal of Plant Science, 84(2):631-668.

Costea M; Weaver SE; Tardif FJ, 2005. The biology of invasive alien plants in Canada. 3. Amaranthus tuberculatus (Moq.) Sauer var. rudis (Sauer) Costea & Tardif. Canadian Journal of Plant Science, 85(2):507-522.

Cullina MD; Connolly B; Sorrie B; Somers P, 2011. The vascular plants of Massachusetts: a county checklist, first revision. Westborough, MA, USA: Massachusetts Natural Heritage & Endangered Species Program (NHESP), 285 pp.

DAISIE, 2015. Delivering Alien Invasive Species Inventories for Europe. European Invasive Alien Species Gateway. www.europe-aliens.org/default.do

Danin A, 2015. Amaranthus rudis Sauer. Flora of Israel Online. http://flora.org.il/en/plants/AMARUD/

Di Castri F; Hansen AJ; Debussche M, 1990. Biological invasions in Europe and the Mediterranean Basin. Dordrecht, Netherlands: Kluwer Academic Publishers, 480 PP.

Felix J; Owen MDK, 1999. Weed population dynamics in land removed from the conservation reserve program. Weed Science, 47(5):511-517.

Ferren Jr WR, 2011. Amaranthaceae of New Jersey. Franklinville, NJ, USA: Flora of New Jersey Project, 9 pp. http://www.njflora.org/the-flora-of-new-jersey/familes-and-genera-recognized-in-new-jersey/

Flora of Delaware, 2015. Flora of Delaware Online Database. Newark, DE, USA: University of Delaware. http://www.wra.udel.edu/de-flora/

Flora of North America Editorial Committee, 2015. Flora of North America North of Mexico. St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria. http://www.efloras.org/flora_page.aspx?flora_id=1

Flora of Wisconsin, 2015. Wisconsin State Herbarium. Madison, USA: University of Wisconsin. http://wisflora.herbarium.wisc.edu/

Franssen AS; Skinner DZ; Al-Khatib K; Horak MJ, 2001. Pollen morphological differences in Amaranthus species and interspecific hybrids. Weed Science, 49(6):732-737.

Franssen AS; Skinner DZ; Al-Khatib K; Horak MJ; Kulakow PA, 2001. Interspecific hybridization and gene flow of ALS resistance in Amaranthus species. Weed Science, 49(5):598-606.

Go Botany, 2015. Discover thousands of New England plants: Amaranthus tuberculatus (Moq.) Sauer. Framingham, MA, USA: New England Wild Flower Society. https://gobotany.newenglandwild.org/species/amaranthus/tuberculatus/

Gower S; Lee C, 2001. Tall waterhemp management in corn and soybeans. Diagnostic Facts, MSU CIPS-DS03, 4 pp. http://web.archive.org/web/20070727005524/http://www.pestid.msu.edu/profiles/TallWaterhemp.PDF

Hager AG; Wax LM; Bollero GA; Stoller EW, 2003. Influence of diphenylether herbicide application rate and timing on common waterhemp (Amaranthus rudis) control in soybean (Glycine max). Weed Technology, 17(1):14-20.

Hager AG; Wax LM; Stoller EW; Bollero GA, 2002. Common waterhemp (Amaranthus rudis) interference in soybean. Weed Science, 50(5):607-610.

Hannick VC; Mink JN; Singhurst JR; Holmes WC, 2013. Annotated checklist of the vascular flora of McLennan County, Texas. Phytoneuron, 2013-29:1-37. http://www.phytoneuron.net/2013Phytoneuron/29PhytoN-McLennan.pdf

Heap I, 2004. International survey of herbicide resistant weeds. http://www.weedscience.com

Hrusa F; Ertter B; Sanders A; Leppig G; Dean E, 2002. Catalogue of non-native vascular plants occurring spontaneously in California beyond those addressed in The Jepson Manual - Part I. Madroño, 49(2):61-98.

Iamonico D, 2010. Amaranthus tamariscinus Nutt. (Amaranthaceae): taxonomical notes on the species and its presence in Italy. Natura Sloveniae, 12(1):25-33. http://web.bf.uni-lj.si/bi/NATURA-SLOVENIAE/pdf/NatSlo_12_1_2.pdf

Iamonico D, 2010. Biology, life-strategy and invasiveness of Amaranthus retroflexus L. (Amaranthaceae) in central Italy: preliminary remarks. Botanica Serbica, 34(2):137-145. http://botanicaserbica.bio.bg.ac.rs/arhiva/pdf/2010_34_2_521_full.pdf

Iamonico D, 2015. Amaranthaceae. Euro+Med PlantBase - the information resource for Euro-Mediterranean plant diversity. http://ww2.bgbm.org/EuroPlusMed/PTaxonDetail.asp?NameCache=Amaranthus&PTRefFk=7300000

Iamonico D, 2015. Nomenclature survey of the genus Amaranthus (Amaranthaceae). Names linked to the Italian flora. Plant Biosystems, in press. http://dx.doi.org/10.1080/11263504.2014.987188

Iamonico D, 2015. Taxonomic revision of the genus Amaranthus (Amaranthaceae) in Italy. Phytotaxa, 199(1):1-84. http://dx.doi.org/10.11646/phytotaxa.199.1.1

Jepson eFlora, 2015. Amaranthus tuberculatus var. rudis. Berkeley, CA, USA: Jepson Herbarium, University of California. http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=91723

Jones RL, 2005. Plant life of Kentucky: an illustrated guide to the vascular flora [ed. by Jones, R. L.]. Lexington, USA: University Press of Kentucky, xvi + 833 pp.

Krausz RF; Young BG, 2003. Sulfentrazone enhances weed control of glyphosate in glyphosate-resistant soybean (Glycine max). Weed Technology, 17(2):249-255.

Manual of the Alien Plants of Belgium, 2015. Welcome to Manual of the Alien Plants of Belgium. Belgium. http://alienplantsbelgium.be/

Mincemoyer S, 2013. Checklist of Montana vascular plants. Helena, MT, USA: Montana Natural Heritage Program, 97 pp. http://mtnhp.org/Docs/060313_MT_Plant_List.pdf

Moquin-Tandon CHBA, 1849. A. tuberculata. In: Prodromus systematis naturalis regni vegetabilis. Pars decima tertia, sectio posterior [ed. by Candolle, A. P. De]. Paris, France: Treuttel & Wurtz, 277.

Mosyakin SL; Robertson KR, 1996. New infrageneric taxa and combinations in Amaranthus (Amaranthaceae). Annales Botanici Fennici, 33(4):275-281.

Mosyakin SL; Robertson KR, 2003. Amaranthus Linnaeus. In: Flora of North America. Volume 4: Magnoliophyta: Caryophyllidae, part 1 [ed. by Flora of North America Editorial Committee]. New York, USA: Oxford University Press, 410-435.

Niekamp JW; Johnson WG, 2001. Weed management with sulfentrazone and flumioxazin in no-tillage soyabean (Glycine max). Crop Protection, 20(3):215-220.

Oldham MJ, 2010. Checklist of the vascular plants of Niagara Regional Municipality, Ontario. Peterborough, Ontario, Canada: Ontario Natural Heritage Information Center, 223 pp.

Patzoldt WL; Dixon BS; Tranel PJ, 2003. Triazine resistance in Amaranthus tuberculatus (Moq) Sauer that is not site-of-action mediated. Pest Management Science, 59(10):1134-1142.

Patzoldt WL; Tranel PJ; Hager AG, 2002. Variable herbicide responses among Illinois waterhemp (Amaranthus rudis and A. tuberculatus) populations. Crop Protection, 21(9):707-712.

Patzoldt WL; Tranel PJ; Hager AG, 2005. A waterhemp (Amaranthus tuberculatus) biotype with multiple resistance across three herbicide sites of action. Weed Science, 53(1):30-36.

Pratt DB; Clark LG, 2001. Amaranthus rudis and A. tuberculatus - one species or two? Journal of the Torrey Botanical Society [Biology of the Amaranthaceae-Chenopodiaceae alliance. Proceedings of a symposium, St. Louis, Missouri, USA, 3 August 1999.], 128(3):282-296.

Rossi G; Montagnani C; Gargano D; Peruzzi L; Abeli T; Ravera S; Cogoni A; Fenu G; Magrini S; Gennai M; Foggi B; Wagensommer RP; Venturella G; Blasi C; Raimondo FM; Orsenigo S, 2013. Red List of the native Italian flora. Policy species and other threatened species (Lista Rossa della flora spontanea italiana. Policy Species e altre specie minacciate). Rome, Italy: Comitato Italiano IUCN, 54 pp.

Sanchez Gullon E; Verloove F, 2013. New records of interesting vascular plants (mainly xenophytes) in the Iberian Peninsula. IV. Folia Botanica Extremadurensis, 7:29-34.

Sarangi D; Sandell LD; Knezevic SZ; Aulakh JS; Lindquist JL; Irmak S; Jhala AJ, 2015. Confirmation and control of glyphosate-resistant common waterhemp (Amaranthus rudis) in Nebraska. Weed Technology, 29(1):82-92. http://www.wssajournals.org/doi/abs/10.1614/WT-D-14-00090.1

Sauer JD, 1972. The dioecious amaranths: a new species name and major range extensions. Madrono, 21:426-434.

Schmitz U, 2002. Dissertationes Botanicae, 364. Dusseldorf, Germany: Heinrich-Heine-Universitat, 132 pp. [Inaugural-Dissertation, Heinrich-Heine-Universitat, Dusseldorf.]

Smith DA; Doll DA; Singh D; Hallett SG, 2006. Climatic constraints to the potential of Microsphaeropsis amaranthi as a bioherbicide for common waterhemp. Phytopathology, 96(3):308-312.

Snow N; Brasher JW, 2004. Provisional checklist of vascular plants for the Southern Rocky Mountain Interactive Flora (SRMIF). Greeley, Colorado, USA: University of Northern Colorado, 306 pp. http://www.unco.edu/biology/environment/herbarium/SRMIF/SRMIFChecklistFeb04.pdf

Steckel LE; Sprague CL, 2004. Common waterhemp (Amaranthus rudis) interference in corn. Weed Science, 52(3):359-364.

Steckel LE; Sprague CL; Hager AG, 2002. Common waterhemp (Amaranthus rudis) control in corn (Zea mays) with single preemergence and sequential applications of residual herbicides. Weed Technology, 16(4):755-761.

Sweat JK; Horak MJ; Peterson DE; Lloyd RW; Boyer JE, 1998. Herbicide efficacy on four Amaranthus species in soybean (Glycine max). Weed Technology, 12(2):315-321.

The Plant List, 2013. The Plant List: a working list of all plant species. Version 1.1. London, UK: Royal Botanic Gardens, Kew. http://www.theplantlist.org

Tranel PJ; Riggins CW; Bell MS; Hager AG, 2011. Herbicide resistances in Amaranthus tuberculatus: a call for new options. Journal of Agricultural and Food Chemistry, 59(11):5808-5812. http://pubs.acs.org/doi/abs/10.1021/jf103797n

Trucco F; Jeschke MR; Rayburn AL; Tranel PJ, 2005. Promiscuity in weedy amaranths: high frequency of female tall waterhemp (Amaranthus tuberculatus) × smooth pigweed (A. Hybridus) hybridization under field conditions. Weed Science, 53(1):46-54.

Trucco F; Tatum T; Robertson Rayburn KRAL; Tranel PJ, 2006. Characterization of waterhemp (Amaranthus tuberculatus) x smooth pigweed (A. hybridus) F1 hybrids. Weed Technology, 20(1):14-22.

Trucco F; Tranel PJ; Jeschke MR; Rayburn LA, 2004. Field hybridization frequencies between monoecious smooth pigweed (Amaranthus hybridus) and dioecious waterhemp (Amaranthus tuberculatus). In: Weed Science Society of America Annual Meeting, Kansas City, 7-11 February 2004. Lawrence, Kansas, USA: Weed Science Society of America, 229.

University of Tennessee Herbarium, 2015. Amaranthus L. Knoxville, USA: University of Tennesse. http://tenn.bio.utk.edu/vascular/database/vascular-search-name-results.asp

USDA-ARS, 2015. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx

USDA-NRCS, 2015. The PLANTS Database. Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov/

Van der Meijden R; Holverda WJ; Van Moorsel RCMJ; Van der Slikke WJ, 2003. New records of rare plants in 2001 and 2002. (Nieuwe vondsten van zeldzame planten in 2001 en 2002.) Gorteria, 29(5):134-154.

Virginia Botanical Associates, 2015. Digital Atlas of the Virginia Flora. Blacksburg, USA: Virginia Botanical Associates. http://vaplantatlas.org/

Waselkov KE; Olsen KM, 2014. Population genetics and origin of the native North American agricultural weed waterhemp (Amaranthus tuberculatus; Amaranthaceae). American Journal of Botany, 101(10):1726-1736. http://www.amjbot.org/content/101/10/1726.short

Wetzel DK; Horak MJ; Skinner DZ; Kulakow PA, 1999. Transfer of herbicide resistance traits from Amaranthus palmeri to Amaranthus rudis. Weed Science, 47(5):538-543.

Contributors

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30/05/2015    Original text by:

Duilio Iamonico, Consultant, Rome, Italy.

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