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Eriogonum capistratum Rev. var. welshii Rev.

Welsh's buckwheat

Polygonaceae (Buckwheat family)

General Description: A low, mat-forming, perennial with blue-green colored foliage. Leaves are covered with dense, soft, white, wooly hairs. They are non-glandular, elliptic to spoon-like in shape, and 5-12 mm long on petioles 4-9 mm long. Flowering stems are leafless, 2-10 cm long, and covered with dense, sometimes tangled, long, wooly hairs. The tight, ball-like inflorescence terminating the flowering stem is subtended by a bell-shaped, 5-7-toothed involucre covered with sparse to dense soft, wooly hairs. Flowers are golden-yellow, without hairs, 2-3 mm long, have a greenish to reddish-brown mid-rib, and become rosy-yellow upon maturity.

Photo © Chris Murphy
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Field Identification Tips: Welsh's buckwheat is distinguished by its low, matted habit, bluish-green leaves covered by white tomentum, and head-like inflorescence of yellow to golden flowers on densely hairy flowering stems.

Phenology: Flowering peaks in late June to early July most years.

Similar Species: Eriogonum mancum (imperfect buckwheat) can be readily distinguished by its cream to pinkish colored tepals when flowers are present. Without flowers it is distinguished by leaves having grayish wooly hairs, versus the white wooly tomentum of Welsh's buckwheat. However, this feature is not always easy to distinguish in the field. Care must be taken to distinguish E. verrucosum (graceful buckwheat) on volcanic substrates near the northern edge of Welsh's buckwheat range. Eriogonum verrucosum is identified by glabrous to only thinly hairy flowering stems and pustulose (with tiny blisters) flowers. In some areas, individuals of Welsh's buckwheat seem to have intermediate characteristics and intergrade with related species known from east-central Idaho. Eriogonum capistratum var. capistratum (hidden buckwheat) has glabrous or glandular flowering stems, but they are not covered with white, wooly hairs.

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Habitat: Primarily on dry, windswept, sparsely vegetated sites characterized by shallow, clay-rich soils. It is found on either calcareous (mainly limestone) or Challis Volcanics substrates, generally on convex-shaped, gently sloping (but sometimes flat or steeper) sites. Occurrences are known from between approximately 6,000 to 7,800 feet elevation. Welsh's buckwheat ranges from valley bottom alluvial fans and benches to foothill ridges and bluffs of the surrounding mountains.

Global Distribution: Endemic to east-central Idaho.

Idaho Distribution: Endemic to the valleys and foothills of the upper Big Lost, Little Lost, and Pahsimeroi rivers, and immediate vicinity, in Custer and adjacent portions of Lemhi and Butte counties in east-central Idaho.

References:

Murphy, C. 2002. The status of Welsh's buckwheat (Eriogonum capistratum var. welshii) in Idaho. Idaho Department of Fish and Game, Conservation Data Center, Boise, ID. 25 pp. plus appendices.