Vascular Plants of North Carolina
Account for Bog Yellowcress - Rorippa palustris   (L.) Besser
Members of Brassicaceae:
Members of Rorippa with account distribution info or public map:
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Section 6 » Order Capparales » Family Brassicaceae
Author(L.) Besser
DistributionThroughout the state, though possibly absent along the eastern coastal areas.

This species occurs across the U.S. and southern Canada.
AbundanceInfrequent to locally fairly common; despite it occurring 3/4th of the counties with specimens, it is not a common species, though a State Rank of S5 is certainly warranted.
HabitatThis is a wetland species of varied habitats, but always in standing or very slowly moving water, and usually in sunny places. It grows along sreamsides, seepages, margins of lakes and ponds (especially in drawdown zones), marshes, ditches, and other similar places.
PhenologyBlooms from May to October, and fruits shortly after flowering.
IdentificationThis is a fairly robust species with a broad stem, up to 2-3 feet tall, sometimes branched. The basal leaves, flat on the ground, are pinnately divided, with the terminal lobe usually elliptical to ovate and 1-inch or more long and wide; lateral lobes are narrow. It has numerous stem leaves, alternate, and highly dissected into pinnate segments, the lobes somewhat rounded but lightly serrated. There are a number of racemes of flowers from upper axils and the end of the stem, with lateral ones usually spreading horizontally. The petals are small but bright yellow. In this species, the flowers are on pedicels, and petals are present; in R. sessiliflora, the flowers are nearly sessile, and petals are absent. This is a "horsey" wetland plant, with many pinnately divided leaves and numerous racemes (often more like rounded clusters) of bright yellow flowers.
Taxonomic CommentsMost older references named it as Rorippa islandica. There are several varieties, of which only the nominate one occurs in NC.

Other Common Name(s)Marsh Yellowcress, Yellow Marshcress
State RankS4 [S5]
Global RankG5
State Status
US Status
USACE-agcpOBL link
USACE-empOBL link
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