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

Rock Buckwheat, Rock Wild Buckwheat, Round-headed Buckwheat

Eriogonum sphaerocephalum

Synonyms: Eriogonum fasciculifolium, Eriogonum geniculatum, Eriogonum sphaerocephalum var. geniculatum

Rock buckwheat as seen on the east bank of the Columbia River near Vantage, WA.........June 22, 2006.

Rock Buckwheat, Rock Wild Buckwheat, Round-headed Buckwheat: Eriogonum sphaerocephalum (Synonyms: Eriogonum fasciculifolium, Eriogonum geniculatum, Eriogonum sphaerocephalum var. geniculatum)

The photo at right shows a close-up of one stem of rock buckwheat (var. sphaerocephalum) as seen on the east bank of the Columbia River along the old highway down to Vantage, WA..........June 22, 2006.

Characteristics:

The rock buckwheat is a large, shrubby perennial plant from 5-40 cm high. The leaves are oblanceolate to linear-spatulate or even linear and are found at the tips of the stems. The leaves are gray woolly below The leaves tend to be more woolly hairy below than above. Long flower stems are leafless except for a whorl of wide spatulate leaves directly at the point where the flower stem branches to give rise to the 2 or 3 round heads of flowers. Shorter flower stems may appear very leafy as it may be difficult to distinguish where the flower stem arises from the leafy stem. (See photos.)

The inflorescence often consists of two umbellate clusters of flowers at the tips of the stems. The involucres are bell-shaped to broadly tubular with 6-10 oblong lobes about 3 mm long and about equal in length to the tube. The flowers are yellow, often white or pinkish, in round clusters atop an umbel.

Varieties of Eriogonum sphaerocephalum:

var. halimioides - Flowers pale yellow to cream or a faint dingy yellow. Inflorescence capitate or umbellate. Leaf blades usually narrowly oblanceolate to narrowly spatulate with non-revolute margins.

var. sphaerocephalum - Flowers bright yellow. Inflorescence umbellate to compound-umbellate. Leaf blades oblanceolate with non-revolute margins (not rolled under).

var. sublineare - Flowers pale yellow to cream or a faint dingy yellow. Inflorescence capitate or umbellate. Leaf blades usually linear-oblanceolate with revolute (rolled under) margins.

Similar Species:

Douglas' Buckwheat: Eriogonum douglasii - Similar to variety sublineare.

Piper's Buckwheat: Eriogonum flavum -

Wyeth Buckwheat: Eriogonum heracloides -

Sulfurflower: Eriogonum umbellatum -

Habitat:

Rockbuckwheat is found amongst sagebrush and juniper in the lowlands to the ponderosa forest at moderate elevations.

Range:

Rock buckwheat may be found from north-central Washington south along the east Cascade slope to northeastern California, and east to western Idaho and Nevada.

The photo above shows a close-up of the umbellate inflorescence of rock buckwheat as seen on the east bank of the Columbia River near Vantage, WA.........June 22, 2006.

Close-up photos of the upper and lower leaf blade surfaces of rock buckwheat as seen on the eastbank of the Columbia River near Vantage, WA.........June 22, 2006. Note how the lower surface is more densely haired with whitish hairs than the upper surface. Note also the inrolled margins to the blades, especially on the younger leaves at left.

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Rock buckwheat as seen along the Gray Butte Trail #852, Crooked River National Grasslands.........June 24, 2017.

Rock buckwheat as seen along the Gray Butte Trail #852, Crooked River National Grasslands........May 20, 2017.

A good view of the woody stem of rock buckwheat as seen on a bald on a ridgeline about one-half mile east of North and South Sulphur Buttes, north edge to the South Fork Crooked Creek Wilderness Study Area.........October 24, 2015.

The photo above shows the leaf of rock buckwheat as seen at the rest area on US Highway 20 to the west of Hines, OR.........June 24, 2003.

Photo above of Eriogonum sphaerocephalum var. sphaerocephalum from roadside on Manastash Ridge (central Washington).....June 22, 1997.

Rock Buckwheat, Rock Wild Buckwheat, Round-headed Buckwheat: Eriogonum sphaerocephalum (Synonyms: Eriogonum fasciculifolium, Eriogonum geniculatum, Eriogonum sphaerocephalum var. geniculatum)

Eriogonum sphaerocephalum along Washington Highway 28, adjacent to Rock Island Dam....June 23, 1997.

The photo above shows rock buckwheat as seen amongst balsamroot at Priest Rapids Dam, Washington Highway 243 in central Washington.......May 10, 1997.

The photo above shows a close-up of the inflorescence of rock buckwheat as seen on arid flats to the south of Winter Ridge, Fremont N.F.........July 19, 1997.

Paul Slichter