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Montana Field Guide

Montana Field Guides

Roughfruit Amaranth - Amaranthus tuberculatus
Other Names:  Rough-fruited Water-hemp, Tall Amaranth, Tall Water-hemp, Waterhemp, Amaranthus tamariscina

Non-native Species

Global Rank: G4G5
State Rank: SNA
C-value: 1

Agency Status


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General Description
Dioecious. Stems erect, 20–80 cm with glabrous foliage. Leaf blade lanceolate to ovate, 2–7 cm long, longer than petiole. Inflorescences narrow, open, axillary spikes and panicles; bracts ovate 1–2 mm long, mucronate. Flowers: sepals 0 to 5, lanceolate, 2–3 mm long; stamens 5. Utricle ca. 1.5 mm, shorter than sepals (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Range Comments
Known in MT only from Missoula County; most of temperate North America and introduced in Europe (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 2

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Relative Density



(Observations spanning multiple months or years are excluded from time charts)



  • Literature Cited AboveLegend:   View Online Publication
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Burns, E.E. 2017. Genetic and physiological characterization and ecological management of non-target site resistance in multiple herbicide resistant Avena fatua L. Ph.D. Dissertation. Bozeman, MT: Montana State University. 175 p.
    • Burns, E.E., B.K. Keith, L.E. Talbert, and W.E. Dyer. 2018. Non-target site resistance to flucarbazone, imazamethabenz and pinoxaden is controlled by three linked genes in Avena fatua. Weed Research 58, no. 1 (February 2018): 8-16.
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Citation for data on this website:
Roughfruit Amaranth — Amaranthus tuberculatus.  Montana Field Guide.  .  Retrieved on , from