17.
Rorippa sinuata
(Nuttall) Hitchcock, Key Spring Fl. Manhattan. 18. 1894. (as Roripa).
Nasturtium sinuatum
Nuttall in J. Torrey and A. Gray, Fl. N. Amer. 1: 73. 1838;
N. trachycarpum
A. Gray;
Radicula sinuata
(Nuttall) Greene;
R. trachycarpa
(A. Gray) Rydberg;
Rorippa trachycarpa
(A. Gray) Greene
Perennials;
(rhizomatous or with creeping roots); sparsely to moderately pubescent, (trichomes hemispherical, vesicular).
Stems
(many to few from base), decumbent or prostrate, branched distally, 1-4.2(-5) dm, (pubescent proximally).
Basal leaves
not rosulate; blade margins pinnatifid.
Cauline leaves
sessile; blade oblong to oblanceolate or lanceolate (lateral lobes oblong or ovate), (1.5-)2.5-6.5(-9) cm × 5-18(-25) mm, base usually auriculate, rarely proximalmost not auriculate, margins pinnatifid to deeply sinuate, or (lateral lobes) dentate to sinuate or entire, (surfaces pubescent abaxially with vesicular trichomes on veins, glabrous adaxially).
Racemes
considerably elongated.
Fruiting pedicels
divaricate-ascending to horizontal, sigmoid or recurved, 4-12(-14.5) mm.
Flowers:
sepals ascending, oblong, 2.2-3.7(-4.5) × 1-1.8 mm; petals yellow, oblanceolate to spatulate, (2.7-)3.2-5.3(-6) × 1.5-2.5 mm; median filaments 3-5.5 mm; anthers narrowly oblong, 1.2-1.7 mm.
Fruits
siliques, curved, oblong to lanceolate or linear, (4-)5-12(-16) × (1-)1.5-2.5 mm; valves glabrous or pubescent; ovules (30-)50-82(-98) per ovary; style (0.8-)1-2.5(-3.5) mm.
Seeds
biseriate, yellow-brown, angled, cordiform, 0.7-1 mm (0.5-0.6 mm diam.), colliculate.
2
n
= 16.
Flowering Apr-Aug. Shores of ponds and lakes, sandy banks, stream banks, fields, wet depressions, gravel banks, ditches, moist grounds; 0-2600 m; Alta., B.C., Ont., Sask.; Ariz., Ark., Calif., Colo., Idaho, Ill., Iowa, Kans., Ky., La., Minn., Mo., Mont., Nebr., Nev., N.Mex., N.Dak., Okla., Oreg., S.Dak., Tenn., Tex., Utah, Wash., Wis., Wyo.
