[Alumroots: The Genus Heuchera in the Columbia River Gorge of Oregon and Washington]

Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot

Heuchera micrantha var. micrantha

Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha

Small-flowered alumroot at the base of the north-facing cliff along the parking area at the mouth of Oneonta Gorge, Columbia River Gorge......mid May, 2004.

Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha The photo at right shows small-flowered alumroot (variety micrantha - note the shallow lobes) as seen at the mouth of the Oneonta Gorge, Columbia River Gorge...........mid May, 2004.
Characteristics:

Small-flowered alumroot is an attractive perennial with several to many slender, brown-colored, hairy stems arising 30-45 cm in height from a cluster of basal leaves. The stems are leafless except for minute bracts within the inflorescence. The basal leaves have long, thin petioles which are several times longer than the length of the blades. The leaf blade is 3-8 cm wide and about as long. The shape is kidney-like or ovate-heart-shaped with 5-7 shallow rounded lobes or 5-7 deeper and more acutely tipped lobes (the major divisions much wider and v-shaped and less deeply cleft (up to 1/3 the length) than those of H glabra. The lobes are coarsely crenate-toothed. The petioles and the undersides of the leaves tend to be covered with long woolly, white hairs.

The inflorescence is an open panicle with many horizontal side branches with clusters of several white flowers. The minute calyx is bell-shaped, measuring 1.5-3 mm long. The white, spatulate petals are clawed and twisted, measuring 2-3 mm long. The stamens and needle-like styles are both long-exserted from the calyx.

Small-flowered alumroot is a great wildflower for the shaded rock garden or woodland plot. In dense plantings, the multiple inflorescences add great texture to the garden. Older plants may become less attractive because the stems elongate, losing their lower leaves, so that the basal leaves are elevated off of the ground. At this point, plants could be dug up and divided into multiple plants.


Varieties:

var. diversifolia: Blades longer than broad, deeply and acutely lobed up to one-third the length. Petioles and lower stems generally strongly woolly-haired. Found primarily in Washington and British Columbia.

var. micrantha: Leaf blades at least as wide as long, shallowly lobed less than one-third the blade length. Petioles and lower stems vary from woolly-haired to subglabrous. Found the Columbia River Gorge south to Marion County in Oregon and east across Oregon to Idaho. Found only occasionally north of the Columbia River Gorge through eastern Washington.


Similar Species:

Smooth Alumroot: Heuchera glabra: Flowers tiny and white in open, spreading panicles. Stamens are strongly exserted beyond the calyx lobes. Leaf blades wider than long (as measured from the sinus where the petiole joins the blade). The blade margins are broadly but acutely toothed, and narrowly cut 1/3-1/2 their length. The base of the flower stem and petioles is glabrous or occasionally glandular-haired.


Habitat:

Small-flowered alumroot may be found on rocky, shady streambanks, rock crevices, and on cliffs and talus slopes in steep sloped areas. It may be found from the lowlands to moderate elevations in the mountains.


Range:

Small-flowered alumroot may be found from British Columbia south in the Cascades (on both sides) to the Sierra Nevada, and west as far as Monterey County, California. It may be found east in Oregon to the Wallowa Mts. and Blue Mts of northeastern Oregon and southeastern Washington and into adjacent Idaho.


Basal leaf of Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha - Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha

A basal leaf of smallflower alumroot as seen along the trail at Angels Rest in the Columbia River Gorge.........May 18, 2009 (photo at left). The photo at right shows the basal leaves of smallflower alumroot as seen in forest along the trail up Mitchell Point several miles west of Hood River, Oregon..........April 19, 2015.

Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha - Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha

Small-flowered alumroot, variety micrantha, as seen along the McCord Creek Trail, western Columbia River Gorge...........May 20, 2009 (left) and May 30, 2009 (right).

Inflorescence of Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha - Leaf of Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha - Flowers of Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha

Small-flowered alumroot as seen under the powerlines along the Starvation Creek Ridge Trail #414, Columbia River Gorge.........April 26, 2015.

Basal leaf of Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha

The photo above shows the leaf blade of small-flowered alumroot, variety micrantha, as seen along the McCord Creek Trail, western Columbia River Gorge...........May 30, 2009.

Ventral leaf surface of Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha - The dorsal leaf surface of Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha - Dorsal leaf surface of Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha

Hairy leaf petiole of Crevice Alumroot, Smallflower Alumroot, Small-flowered Alumroot: Heuchera micrantha var. micrantha

Additional close-up views of the leaves of small-flowered alumroot (var. micrantha) as seen along the Triple Falls Loop in the western Columbia River Gorge...........February 12, 2011. Note the spreading hairs on the leaf petioles.

Paul Slichter