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Northeast Wetland Flora

Field Office Guide to Plant Species

True Water-cress
Nasturtium officinale R. Br. in W.T. Ait.

JPG -- Species Photo JPG -- Distribution Map

Family: Mustard (Cruciferae)
Flowering: April-October
Field Marks: Water-cress differs from all other mustards by its pinnately compound leaves with 3-11 leaflets, its 4 white petals about twice as long as the sepals, and its long, slender, straight or curving pods, and with seeds in two rows.
Habitat: Springs, brooks, cool water, usually in water.
Habit: Perennial herb with fibrous roots.
Stems: Creeping or floating, rather fleshy, smooth, rooting at many of the nodes.
Leaves: Alternate, pinnately compound, with 3-11 leaflets; leaflets oblong to oval to nearly spherical, rounded at the tip, smooth, without teeth or with wavy-toothed margins.
Flowers: Borne in terminal racemes and in racemes from the axils of the uppermost leaves, each flower 1/6-1/4 inch across, not subtended by bracts.
Sepals: 4, green, free from each other, elliptic to narrowly oblong, smooth, up to 1/8 inch long.
Petals: 4, white, free from each other, broadly oblong to nearly spherical, rounded at the tip, up to 1/4 inch long.
Stamens: 6.
Pistils: Ovary superior, smooth.
Fruits: Pods elongated, linear, cylindric, straight or curved, on slender stalks, smooth, up to 1 1/4 inches long, up to 1/8 inch thick, with or without a minute beak at the tip.
Notes: This species is collected for use in salads or as a garnish. This family is called Brassicaceae by Gleason and Cronquist.

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