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Northern Prairie Wildlife Research Center

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Aquatic and Wetland Vascular Plants of the Northern Great Plains

22. Brassicaceae, the Mustard Family

4. Rorippa Scop. -- Yellow cress

5. Rorippa sinuata (Nutt.) A.S. Hitchc. -- Spreading yellow cress

Decumbent to prostrate, branched perennial from rhizomes, the stems 1-5 dm long, sparsely to densely pubescent with hemispherical vesicular trichomes. Leaves sessile, auriculate and clasping to nonauriculate and nonclasping, the blades oblong to oblanceolate, 1.5-6 cm long, 0.4-2 cm wide, glabrate on the upper surface, sparsely to densely covered with vesicular trichomes on the midrib beneath, acute to mucronate, the margin shallow to deeply sinuate, pinnatifid to subpinnatifid, the lobes entire to slightly toothed. Racemes terminal and axillary, all about the same age or the axillary ones with the oldest siliques. Sepals, yellowish-green, 2.7-4.5 mm long, caducous; petals bright yellow, 3-5.5(6) mm long, to 3 mm longer than the sepals. Siliques short to elongate-cylindrical, straight to strongly curved upward, 5-12 mm long, 1-2 mm thick, tapered to the style, the valves glabrous or roughened with hemispherical trichomes; pedicels strongly recurved to divergent or ascending, 4-10 mm long. Jun--Aug. Stream banks, ditches, wet meadows and other low places; occasional in the c and w ND, MT, SD, WY and NE; (IL to s Sask. and WA, s to AR, OK, n TX, NM, AZ and CA).
GIF- Distribution Map

Map key

Previous Species -- Rorippa palustris (L.) Bess. -- Bog yellow cress
Return to Family -- Brassicaceae - The Mustard Family
Next Species -- Rorippa sylvestris (L.) Bess. -- Creeping yellow cress

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