[The Rock Cress of the Columbia River Gorge of Oregon and Washington]

Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress

Arabis furcata var. furcata

Synonym: Arabis furcata

Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

What may be Cascade rockcress as seen in Starvation Creek State Park, Columbia River Gorge..........April 26, 2015. Plants here ranch from 15-35 cm high, and many live on steep, moss-covered gravel or talus slopes under open forest canopy.

Characteristics:

Cascade rockcress is a pretty, tufted wildflower with one to several erect stems from 5-35 cm tall arising from a rosette of basal leaves. The herbage is mostly smooth, with straight hairs occasionally found near the base. The basal leaves are from 2-5 cm long and up to 2 cm wide with oblanceolate to obovate blades. The margins are entire or sometimes with shallow teeth. The basal leaves may have some simple or branched hairs on the surface. The 2-5 stem leaves are oblong to oblanceolate, sessile, and the uppermost often auriculate-clasping.

The racemes are 5-30 flowered with white flowers. The sepals are from 2.5-3.5 mm long and the petals from 6-9 mm long. The seed capsules are erect siliques from 2.5-4 cm long and 1.5-2 mm wide (See photo below.).


Habitat:

Cascade rockcress is a wildflower of upper elevations of the Cascades, including alpine ridges and subalpine meadows.


Range:

Cascade rockcress is found in the Cascade Mts. from Chelan County, WA south to central Oregon, and in the Olympic Mts.

In the Columbia River Gorge, it may be found at low elevation (100'-4800') between Shellrock Mt and Viento State Park.


Flower of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Sepals and outer petal details of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Sepals and outer petal details of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Inflorescence of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Upper leaf surface details of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Upper leaf surface details of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Basal leaves of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Flowers of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Stem leaves and inflorescence of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Inflorescence of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Basal leaf rosette of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Stem leaves of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Stem leaves of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Inflorescence of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Stem leaf of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Ventral surface of a basal leaf blade of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Upper surface and hairs on leaf margins of a basal leaf of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Habitat view of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Habitat view of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Cascade rockcress as seen in Starvation Creek State Park, Columbia River Gorge..........April 26, 2015. Associated species seen in these photos include Hylocomium splendens, Leucolepis acanthoneuron, Rhytidiadelphus triquetrus, Selaginella douglasii, Berberis nervosa, Delphinium nuttallianum, Heuchera micrantha var. micrantha, Polypodium glycyrrhiza, Rubus ursinus, and Nemophila parviflora var. parviflora.

Flowers of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Cascade rockcress as seen in Starvation Creek State Park, Columbia River Gorge..........May 7, 2015.

Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Pods of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Flower of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata) - Inflorescence of Cascade Rockcress, Columbia Gorge Rockcress, Fork-haired Rockcress: Arabis furcata var. furcata (Synonym: Arabis furcata)

Photos of Cascade rock cress from Mt. Adams. Note the narrow stem leaves.

Paul Slichter