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Rorippa palustris   (L. ) Besser
Konza Prairie, Riley County, Kansas
Annual, occasionally perennial
Height: 4-40 inches
Family: Brassicaceae - Mustard Family
Flowering Period:   May, June, July, August, September,October
Stems: Erect, simple or branched distally, usually glabrous, rarely pubescent proximally.
Leaves: Basal and cauline, alternate, simple. Basal leaves: petiole present; blade oblong to oblanceolate in outline, 1.6 to 8(-12) inches long, .4 to 2.4 inches wide, margins incised to deeply pinnately lobed surfaces glabrous or hirsute abaxially with simple hairs. Cauline leaves: petiole present or absent; blade oblanceolate to oblong or lanceolate, .8 to 4(-7) inches long, .2 to 1.2 inch wide; base auricled and clasping stem.
Inflorescences: Racemes, terminal.
Flowers: Sepals 4, distinct; ovate to oblong, .05 to .16 inch; petals 4, yellow or greenish yellow, oblong to broadly spatulate, .06 to .12 inch, shorter than to as-long-as sepals; stamens 6; style 1; stigma 1.
Fruits: Fruiting pedicels ascending, spreading, or recurved, .08 to .24 inch. Siliques, sessile, spreading to ascending, ellipsoid to oblong, short-cylindric, or pear-shaped, .12 to .4 inch long, .06 to .14 inch wide; seeds yellowish brown to brown, heart-shaped, minutely papillose.
Habitat: Muddy to sandy shores of rivers, streams, and ponds, marshes, ditches, wet depressions.
Distribution: Throughout Kansas
Origin: Native
Comments: Rorippa, a Saxon name, and palustris, marshy. Two subspecies have been reported in Kansas: subsp. hispida (Desv.) Jonsell has stems and leaves densely hirsute; subsp. palustris has stems and leaves glabrous or sparsely pubescent.

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