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Montana Field Guide

Montana Field Guides

Onerow Watercress - Rorippa microphylla
Other Names:  Nasturtium microphyllum

Non-native Species

Global Rank: GNR
State Rank: SNA

Agency Status
MNPS Threat Rank:
C-value: 1

External Links

General Description
Perennial from fibrous-rooted rhizomes. Stems prostrate or floating, hollow, 10–50 cm long. Leaves all cauline, petiolate, 2–6 cm long; the blades pinnately compound with lanceolate to elliptic lateral lobes and an elliptic terminal segment. Petals white, 4–5 mm long. Fruit a linear silique, 8–12 mm long, ca. 0.5 mm wide; style ca. 1 mm long; pedicels spreading to ascending, 8–12 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Range Comments
Introduced in much of north-temperate North America, native to Europe (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 4

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Relative Density



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


The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus rufocinctus (Thorp et al. 1983).


  • Literature Cited AboveLegend:   View Online Publication
    • Thorp, R.W., D.S. Horning, and L.L. Dunning. 1983. Bumble bees and cuckoo bumble bees of California (Hymenoptera: Apidae). Bulletin of the California Insect Survey 23:1-79.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
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Citation for data on this website:
Onerow Watercress — Rorippa microphylla.  Montana Field Guide.  .  Retrieved on , from