Northern Prairie Wildlife Research Center
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).
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