Semi-desert, foothills, montane. Springs, streams. Summer.
Above: Roadside irrigation water, Lewis, June 14, 2015.
Left: Grandstaff Canyon, Utah, April 1, 2004.

Watercress was introduced from Europe and is now quite at home (even in grocery stores) throughout the United States  --  and the entire world.  Its tiny white flowers float on stems just above the water or the stems can be up to several feet long.  The plant has a pleasant peppery taste but it can be unsafe to consume this plant in the wild because of contaminated water.

In 1753 Linnaeus named this species Sisymbrium nasturtium-aquaticum and in 1812 Robert Brown renamed it Nasturtium officinale. "Nasturtium" is apparently from the Latin "nasus tortus", "twisted nose", referring to the contortions human noses go through because of the sharp, peppery smell of Nasturtium officinale seeds.  "Officinale" is Latin for "of the shops", indicating that the plant has at some time been accepted as an official herb/drug that could be bought in "shops", a word used centuries ago for "apothecaries". 

Semi-desert, foothills, montane. Springs, streams. Summer.
Grandstaff Canyon, April 1, 2004.

Nasturtium officinale forms thick mats because it spreads by rhizomes or stolons.

Leaves can be entire, as shown at left, or, as shown in the last photograph below, pinnate, i.e., cut into leaflets.

Semi-desert, foothills, montane. Springs, streams. Summer.
Roadside irrigation water, Lewis, June 14, 2015.

Morning dew glistens on minute petals.

Semi-desert, foothills, montane. Springs, streams. Summer.
Roadside irrigation water, Lewis, June 14, 2015.

Flowers are usually white but may appear white in glaring sunlight, yet actually have tinges of purple.

Young seed pods (siliques) in this photograph are almost a centimeter long.

Notice the grooved, angled stem.

Semi-desert, foothills, montane. Springs, streams. Summer.
Roadside irrigation water, Lewis, June 14, 2015.

Leaves are usually glabrous, but they may be sparsely pubescent.

The end leaflet is longer and broader than the side leaflets.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Nasturtium officinale