[Buckwheats: The Genus Eriogonum East of the Cascade Mts. of Oregon and Washington]

Slender Buckwheat, Slenderbush Buckwheat, Slender Wild Buckwheat

Eriogonum microthecum var. microthecum

Synonym: Eriogonum microthecum var. idahoense

The photo above shows a close-up of part of the inflorescence of slenderbush buckwheat (variety microthecum) as seen along US Highway 26 east of Mitchell, OR.......September 6, 1999.

Slender Buckwheat, Slenderbush Buckwheat, Slender Wild Buckwheat: Eriogonum microthecum var. microthecum (Synonym: Eriogonum microthecum var. idahoense)

The photo at right shows a close-up of part of the upper stem and unopened inflorescence of slenderbush buckwheat (variety microthecum) as seen along US Highway 26 east of Mitchell, OR.......September 6, 1999.

Characteristics:

Slenderbush buckwheat is a shrubby, erect perennial with leafy stems and a flat-topped, umbel-like inflorescence.Plants range from 10-40 cm high. The leaf blades are linear, oblong, linear-oblanceolate or narrowly obovate in shape and narrow gradually to a short petiole. The blades are somewhat tomentose but green on the upper surfaces and gray tomenotse below. Entire leaves range from 1-3 cm long. The leaves are numerous on the stems and may be found over half the length of the flower branches.

The inflorescence is like a freely-branched umbel that is two to six times divided. The conical involucres are are borne singly, 2-2.5 mm long and with glabrous to sparsely tomentose involucres. The white, pink or yellow perianth is 2-2.5 mm long and glabrous externally. The perianth parts are united half their length with the outer lobes rounded and the inner lobes much narrower.

Varieties:

Variety effusum: Plants with white or pink flowers. Leaves 2-4 cm long but without curled margins. The inflorescence ranges from 6-20 cm long. Found from southeastern Idaho east to southern Montana, Utah and New Mexico.

Variety laxiflorum: Plants with white or pink flowers. Leaves up to 2 cm long and typically with curled margins. The inflorescence is less than 5 cm long. Found from northcentral Washington and east to northern Montana, Wyoming, Colorado and Nebraska and southward to Nevada and California.

Variety microthecum: Plants with yellow flowers. Plants of the John Day River Valley and also found around Weiser, Idaho.

Habitat:

Slenderbush buckwheat is found in the arid plains and low mountains slopes, often amongst sagebrush.

The lower leaf surface (left) and upper leaf surface (right) of slenderbush buckwheat (variety microthecum) as seen at Camp Hancock in central Oregon..........May 15, 2010.

Range:

Slenderbush buckwheat may be found from the eastern base of the Cascade Mts from central Washington south to California and the Sierra Nevada mts and east to Montana, Nebraska, Colorado, New Mexico and Arizona.

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Examples of slender buckwheat as it begins to bloom along Oregon Highway 19 at Cathedral Rock, John Day Fossil Beds National Monument..........August 4, 2011.

Several views of slender buckwheat as seen on basalt cliffs above the John Day River at the junction of US Highway 26 and Oregon Highway 19, Grant County, Oregon..........June 2, 2011.

The photo above shows the upper stems and inflorescences of slenderbush buckwheat (variety microthecum) as seen along US Highway 26 east of Mitchell, OR.......September 6, 1999.

Paul Slichter