Eriogonum arcuatum var. xanthum

(Small) Reveal

Harvard Pap. Bot. 9: 157. 2004.

Common names: Ivy League wild buckwheat
Endemic
Basionym: Eriogonum xanthum Small Bull. Torrey Bot. Club. 33: 51. 1906
Synonyms: Eriogonum chloranthum Greene Eriogonum flavum subsp. chloranthum (Greene) S. Stokes Eriogonum flavum var. xanthum (Small) S. Stokes Eriogonum jamesii var. xanthum (Small) Reveal
Treatment appears in FNA Volume 5. Treatment on page 370. Mentioned on page 369.

Plants compact mats, 3–10 dm wide. Aerial flowering stems 0.2–0.8 dm. Leaf blades oblanceolate to oblong, 1–2.5 × 0.5–1 cm. Inflorescences capitate, often reduced to single involucre; bracts 0.3–1 × 0.2–0.7 cm. Involucres 4–6 × 3–5 mm. Flowers 6–7 mm.


Phenology: Flowering Jul–Sep.
Habitat: Sandy, gravelly to rocky or talus slopes, high-elevation grassland, sagebrush, and tundra communities, alpine conifer woodlands
Elevation: (2600-)3000-4000(-4200) m

Discussion

Variety xanthum is the subalpine to alpine expression of the species and is distributed along the backbone of the Colorado Rocky Mountains on many of the highest peaks (Chaffee, Clear Creek, Custer, El Paso, Fremont, Grand, Hinsdale, Huerfano, Lake, Larimer, Park, Saguache, Summit, and Teller counties). The plants are rather exquisite in the field and do well in cultivation.

Selected References

None.

Lower Taxa

None.
James L. Reveal +
(Small) Reveal +
Eriogonum xanthum +
Ivy League wild buckwheat +
(2600-)3000-4000(-4200) m +
Sandy, gravelly to rocky or talus slopes, high-elevation grassland, sagebrush, and tundra communities, alpine conifer woodlands +
Flowering Jul–Sep. +
Harvard Pap. Bot. +
Eriogonum chloranthum +, Eriogonum flavum subsp. chloranthum +, Eriogonum flavum var. xanthum +  and Eriogonum jamesii var. xanthum +
Eriogonum arcuatum var. xanthum +
Eriogonum arcuatum +
variety +