Northern Prairie Wildlife Research Center
Sessile-flowered Cress (Rorippa sessiliflora)
- Family: Mustard (Brassicaceae)
- Flowering: April-November.
- Field Marks: Rorippas are wetland herbs with small, yellow, 4-parted flowers. This species differs from others in the genus by its flower stalks less than 1/6 inch long, its coarsely toothed leaf segments, and its 4 stamens.
- Habitat: Around ponds and lakes, along streams, swampy ground, sloughs.
- Habit: Annual or biennial herbs from slender taproots.
- Stems: Erect, usually branched, smooth, up to 18 inches tall.
- Leaves: Basal leaves deeply lobed or divided, up to 4 inches long; the leaves on the stem alternate, undivided or sparsely divided, oblong to broadly lanceolate, rounded at the tip, tapering to the base, toothed, smooth, up to 1 1/2 inches long.
- Flowers: Several flowers in terminal or axillary racemes; each flower yellow, about 1/12 inch across, on very short stalks.
- Sepals: 4, green, free from each other.
- Petals: 4, yellow, free from each other.
- Stamens: 4.
- Pistils: Ovary superior.
- Fruits: Pods oblong, thickened, green, beaked at the tip, up to 1/2 inch long.
Previous Species -- Celeryleaf Buttercup (Ranunculus sceleratus)
Return to Species List -- Group 8
Next Species -- Creeping Yellow-cress (Rorippa sylvestris)