Naked-stemmed Buckwheat

Naked Buckwheat, Nude Buckwheat, Ear-shaped Wild Buckwheat
Eriogonum nudum var. auriculatum
NATIVE – CA ENDEMIC

Description (Jepson, PlantID.net)

• Eudicotyledon
  • Eudicots are a major lineage of flowering plants; see family for general characteristics
• Buckwheat Family (Polygonaceae)
• Perennial, drought tolerant herb
• Leaves
  • Mostly basal, with wavy margins
  • Smooth dark-green upper surface; underside with short woolly hairs (tomentose)
  • Leaf base surrounds the stem (sheathing)
• Flowers
  • Inflorescence (flower arrangement) of long, leafless, branching stems with rounded flower clusters at nodes and tips
  • Each cluster of individual flowers held in 1-5 bunches of vase-like bracts (modified leaves), called involucres, attached directly to the stem
  • White to pink
  • Ovary superior (above the attachment of other flower parts)
• Fruit is an achene (a single-seeded, dry fruit that does not split open)
• Height to 5 ft. (Jepson)
  • At Edgewood, rarely exceeds 3 ft.

Distribution

• Native and endemic (limited) to California
  • Grows in sandy, clay, or gravel soils on exposed, sunny sites in mixed grasslands, chaparral, and oak and conifer woodlands
  • See Calflora for statewide observations for this plant
• Grows at elevations to 4,000 ft.

Uses (San Mateo County Parks prohibits removal of any natural material)

• Wildlife
  • Supports a large and varied community of insects, including nectar- and pollen-eating bees and predatory insects, like wasps
  • Native buckwheats (Eriogonum species), in general, are valuable larval food sources (hosts) for butterflies and moths, e.g. Acmon blue (Plebejus acmon), Gorgon copper (Lycaena gorgon), and bramble hairstreak (Callophrys perplexa)
    • Caterpillars of some butterfly species are monophagous and will feed on only one genus or one species of plant
      • Lange’s metalmark (Apodemia mormo langei) larvae, for example, only feed on Eriogonum nudum var. auriculatum
      • Exclusive association to a plant can increase possibility of coextinction (Everipedia 2020)
  • Birds and small mammals eat the seeds
• Native people
  • Ate leaves
  • Hollow stems used as drinking tubes or for smoking pipes

Name Derivation

• Eriogonum (er-ee-OG-an-um) – from the Greek erion, “woolly,” and gónato, “knee,” referring to the hairy nodes (joints) of some species
• nudum (NOO-dum) – Latin for “bare” or “naked”
• auriculatum (aw-rik-yoo-LAY-tum) – from the Latin auris, “ear,” meaning “having ear-like structures”
• Buckwheat – from Old English for “beech-wheat”
  • 3-sided seeds resemble beechnuts
  • Though not related to wheats, which are in the Grass family, the seeds of some buckwheats are ground into meal or flour

Notes

• Although in the same family, the cultivated buckwheat (Fagopyrum esculentum), which is native to Asia, is not closely related to Edgewood’s native buckwheats; see Buckwheat family to learn more about this pseudograin
• In 2016, a large population of Mount Diablo buckwheat (Eriogonum truncatum) was discovered at Black Diamond Mines Regional Preserve in Antioch (Save Mount Diablo 2016)
  • The species was thought extinct for almost 70 years until rediscovered in 2005 in a single, tiny population on Mount Diablo
  • This rare buckwheat is on protected land, but many plant species that have evolved to fill specific ecological niches (contributing to the extraordinary diversity of California’s plants and animals) grow in undeveloped lands that are subject to intense development pressures
• Edgewood’s naked-stemmed buckwheat is classified as a variety
  • Variety indicates a population with small morphological variations, e.g. color, seen throughout the geographic range of the species; interbreeding is possible
  • Subspecies indicates a geographically-separated population with distinct morphological characteristics; when not isolated, interbreeding is possible
  • In practice, botanists have not consistently applied these ranks

ID Tips

• May be confused with the 2 other buckwheat species at Edgewood
  • Wicker buckwheat (E. luteolum var. luteolum), which grows in the serpentine barrens
  • California buckwheat (E. fasciculatum), a few specimens of which grow on the slopes of the Central Ridge and in the Native Garden
    • Introduced via an early restoration effort; this species is outside its natural range

	Wicker Buckwheat	Naked-stemmed Buckwheat	California Buckwheat
Growth Habit	annual herb	herbaceous perennial	evergreen shrub
Height	≤ 2 ft.	≤ 3 ft..	≤ 8 ft.
Leaves	mostly basal	mostly basal	clusters alternate along stem
Inflorescence	tiny clusters along wiry stems	clusters at nodes and tips of branching stems	clusters radiating from tips of long stems

At Edgewood

• Found in serpentine grasslands
  • See iNaturalist for observations of Eriogonum nudum
• Flowers June – September

See General References

Specific References

Everipedia International. 2020. Eriogonum.

Hammerstrom, K. 2016, Nov. 16. California native plant profile: Buckwheat. Blog. UC Master Gardeners of Monterey Bay. University of California Agriculture and Natural Resources (UC ANR).

Hemingway, M. 2012. Naked buckwheat Eriogonum nudum Dougl. Plant Guide. United States Department of Agriculture, Natural Resources Conservation Service, Plant Materials Center, Corvallis, Oregon.

Save Mount Diablo. 2016, Oct. 1. Mount Diablo buckwheat critically endangered wildflower discovered near Antioch. Blog.

Shapiro, A.M. and T.D. Manolis. 2007. Field Guide to Butterflies of the San Francisco Bay and Sacramento Valley Regions. University of California Press, Berkeley and Los Angeles, California.