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Eriogonum umbellatum

Eriogonum umbellatum
Eriogonum umbellatum var. hypoleium
Conservation status
Secure  (NatureServe)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Order:	Caryophyllales
Family:	Polygonaceae
Genus:	Eriogonum
Species:	E. umbellatum
Binomial name
Eriogonum umbellatum Torr.

Eriogonum umbellatum is a species of wild buckwheat known by the common name sulphurflower buckwheat, or simply sulphur flower.

Description[edit]

It is an extremely variable plant and hard to identify because individuals can look very different from one another. Also, there are many varieties. It may be a perennial herb blooming by summer^[1] with stems 10 centimetres (4 in) tall^{[citation needed]} and two to six clusters of flowers, with a whorl of leaves below the stems,^[1] or a sprawling shrub approaching 2 metres (6+1⁄2 ft) high and wide.^{[citation needed]} The leaves are usually woolly and low on the plant, and the flowers come in many colors from white to bright yellow to purple.

Varieties[edit]

• E. u. var. argus - often nearly hairless leaves and bright yellow flowers; limited to the Klamath Mountains
• E. u. var. dichrocephalum - found throughout much of the western United States
• E. u. var. furcosum - a low shrub native to the Sierra Nevada
• E. u. var. glaberrimum - (green buckwheat) - a nearly hairless, white-flowered species
• E. u. var. humistratum - (Mt. Eddy buckwheat) - a rare northern California endemic
• E. u. var. juniporinum - (juniper buckwheat) - an uncommon plant of eastern California and western Nevada
• E. u. var. subalpinum - (sulfur buckwheat) - similar to Eriogonum eriogonum but has wider and more spoon-shaped leaves
• E. u. var. torreyanum - (Donner Pass buckwheat) - known from fewer than 10 occurrences near the Donner Pass
• E. u. var. versicolor - bears pinkish-brown flowers with bright stripes

Distribution and habitat[edit]

It is native to western North America from CaliforniatoColorado to central Canada, where it is abundant and found in many habitats, including the sagebrush steppe and alpine areas.^[1]

Ecology[edit]

It is a popular larval host, feeding the bramble hairstreak, desert green hairstreak, lupine blue, Mormon metalmark, Rocky Mountain dotted blue, Sheridan's hairstreak, Sonoran metalmark, and western green hairstreak.^[2] Additionally, goats and domestic sheep feed on the plant.^[3]

Cultivation[edit]

The wildflower gardening author Claude A. Barr complemented sulphurflower buckwheat as a "treasure in appearance and in adaptation in my garden."^[4] It is valued for its very low water usage for xeriscaping. The cultivar "Kannah Creek", a selection of Eriogonum umbellatum var. aureum, has been introduced to the garden trade by the Plant Select cooperative sponsored by Colorado State University and Denver Botanic Gardens.^[5][6] It grows in USDA zones 4–8.^[7]

• 
  E. umbellatum var. dichrocephalum
• 
  E. umbellatum var. humistratum (habit)
• 
  E. umbellatum var. humistratum (flowers)
• 
  E. umbellatum var. hypoleium (habit, William O. Douglas Wilderness)
• 
  E. umbellatum var. hypoleium (flowers)
• 
  E. umbellatum var. majus (flowers, Wenatchee Mountains)
• 
  E. umbellatum var. subaridum (flowers, Spring Mountains)

References[edit]

External links[edit]

• Media related to Eriogonum umbellatum at Wikimedia Commons
• Jepson Manual Treatment
• Ethnobotany
• Photo gallery