Rorippa palustris (Bog Yellow-cress)
|Also known as:||Marsh Yellow Cress|
|Life cycle:||annual, short-lived perennial|
|Habitat:||part shade, sun; wet ditches, wet meadows, along shores, swamps, mud flats|
|Bloom season:||May - September|
|Plant height:||12 to 40 inches|
|Wetland Indicator Status:||GP: OBL MW: OBL NCNE: OBL|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Elongating clusters at the end of branching stems and arising from the leaf axils, with a small compact flower head at the tip and fruit developing below it. Flowers are about 1/8 inch across with 4 nearly indistinct spatula-shaped petals alternating with 4 yellowish green oblong sepals that are about as long as the petals. 6 yellow stamens and a stout style are in the center
Leaves and stems:
Leaves are somewhat variable, 3 to 7 inches long, oblong or egg- to lance-shaped, coarsely toothed and may be hairy on the underside. Basal leaves are stalked, basal and lower leaves usually with a few to several deep, narrow lobes and a large lobe at the tip end. Stem leaves become smaller, unlobed with little or no stalk in the upper plant. Stems are green or tinged red and may be hairy, depending on the variety.
Fruit is a cylindrical pod about 1/3 inch long, bulging slightly with the developing seed, and the remains of the style persisting at the tip. The stalks are held straight out, with the pod usually angled up slightly.
There are 2 subspecies of Bog Yellow-cress found in Minnesota: subsp. hispida, with leaves that are hairy on the underside as well as a hairy stem, and subsp. palustris, which is smooth throughout. While the flowers are similar to some Descurainia (tansy mustard) species, the shape of the leaves and fruits are different enough to distinguish them from Bog Yellow-cress.
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Where to buy native seed and plants ↓
- Bog Yellow-cress plant
- more plants
- early growth, basal rosette
- stem arising from a leaf axil
- unbranched plant
Photos by K. Chayka taken in Ramsey County. Photos courtesy Peter M. Dziuk taken in Anoka County.
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