Bog Yellowcress, Fernald's Yellowcress, Marsh Yellowcress, Northern Marsh Yellowcress, Smooth Marsh Yellowcress, Western Bog Yellowcres, Yellow Bogcresss
Rorippa palustris ssp. palustris
Synonyms: Rorippa islandica var. fernaldiana,Rorippa islandica var. glabrata, Rorippa islandica var. glabrata, Rorippa islandica var. occidentale, Rorippa islandica var. occidentalis, Rorippa palustris ssp. fernaldiana, Rorippa palustris ssp. occidentalis, Rorippa palustris var. fernaldiana, Rorippa palustris var. glabra, Rorippa palustris var. occidentalis
Marsh yellowcress as seen on the cobbly Columbia River shoreline just east of the Sandy River Delta, Troutdale, Oregon.............September 8, 2012.
The
photo at right shows one of the large leaves of the lower stem with coarse teeth
towards its tip with entire margins on the lower two-thirds of the the blade.
The lower leaf is more typical of one of the pinnately lobed leaves found higher
on the stems.
Characteristics:
Yellow marshcress is an annual herb with erect, simple to branched
stems from 40-100 cm tall. The herbage ranges from glabrous to having hairs
on the stems. The leaves are highly variable, with the lower leaves pinnately
divided while the smaller upper leaves have shallow lobes or irregular teeth
along the margins. The lower leaves range up to 17 cm in length.
The inflorescence is a short raceme with the flower stalks up-curved
and 3-12 mm long. The individual flowers have 4 yellowish petals, the petals
spoon-shaped and from 1-2.5 mm long The fruits are egg-shaped siliques which
range from 2-12 mm long and up to 3 mm wide. The siliques are spreading to ascending.
Habitat:
Yellow marshcress may be found in wet places along rivers and
streams, in sloughs or on the shores of ponds and shallow lakes.
Range:
Yellow marshcress may be found across much of North America
to the north of Mexico.
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Marsh yellowcress as seen (left) on the cobbly Columbia River shoreline just east of the Sandy River Delta, Troutdale, Oregon.............September 8, 2012. Note the grayish, perennial stem below the new flush of green growth which helps the plant survive between seasons during which the site is innundated by several feet of river water. The photo at right shows in a vernally moist swale several hundred meters uphill from the parking area at
Catherine Creek, Columbia River Gorge............May2, 2014.
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Yellow marshcress found in a vernally moist swale several hundred meters uphill from the parking area at
Catherine Creek, Columbia River Gorge............November 4, 2016.
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Yellow marshcress leaves found in a vernally moist swale several hundred meters uphill from the parking area at
Catherine Creek, Columbia River Gorge............November 9, 2023.
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Yellow marshcress found in the dry water course
of Catherine Creek in the Columbia River Gorge............May 13, 2000.
Paul Slichter