Eriogonum microthecum var. laxiflorum

Hooker
Hooker’s J. Bot. Kew Gard. Misc. 5: 264. 1853.
Common names: Great Basin wild buckwheat
Synonyms: Eriogonum confertiflorum Bentham Eriogonum microthecum subsp. confertiflorum (Bentham) S. Stokes Eriogonum microthecum subsp. laxiflorum (Hooker) S. Stokes
Treatment appears in FNA Volume 5. Treatment on page 244. Mentioned on page 245, 246, 247.

Subshrubs, (1–)2–4(–5) × 3–8 dm. Stems: caudex absent; aerial flowering stems 0.2–0.6(–0.8) dm, floccose or tomentose, rarely glabrous. Leaf blade usually elliptic, (0.5–)1–2(–2.5) × (0.1–)0.2–0.6(–0.8) cm, densely to sparsely whitish-tomentose abaxially, less so to sparsely whitish-floccose adaxially, margins not revolute. Inflorescences (1–)2–4(–8) cm; branches floccose or glabrous. Involucres 2–3(–3.5) mm, subglabrous, glabrous, or merely floccose between angled ridges. Flowers 2–3 mm; perianth white to pink or rose. Achenes 2–3 mm.


Phenology: Flowering Jun–Oct.
Habitat: Sandy to gravelly flats and slopes, mixed grassland, saltbush, blackbrush, and sagebrush communities, pinyon-juniper and montane conifer woodlands
Elevation: (400-)1500-3200 m

Distribution

V5 447-distribution-map.gif

Ariz., Calif., Colo., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo.

Discussion

Variety laxiflorum is the common expression of the species in the northern part of the species’ range. It occurs in northern Arizona, eastern California, western Colorado, central and southern Idaho, southwestern Montana, Nevada, eastern Oregon, northern and western Utah, eastern Washington, and southwestern Wyoming. It overlaps morphologically with var. simpsonii in northern Arizona. The variety is the primary host plant for the rare Mattoni blue butterfly (Euphilotes rita mattoni).

Selected References

None.

Lower Taxa

None.

James L. Reveal +
Hooker +
Undefined subg. Eucycla +
Great Basin wild buckwheat +
Ariz. +, Calif. +, Colo. +, Idaho +, Mont. +, Nev. +, Oreg. +, Utah +, Wash. +  and Wyo. +
(400-)1500-3200 m +
Sandy to gravelly flats and slopes, mixed grassland, saltbush, blackbrush, and sagebrush communities, pinyon-juniper and montane conifer woodlands +
Flowering Jun–Oct. +
Hooker’s J. Bot. Kew Gard. Misc. +
Eriogonum confertiflorum +, Eriogonum microthecum subsp. confertiflorum +  and Eriogonum microthecum subsp. laxiflorum +
Eriogonum microthecum var. laxiflorum +
Eriogonum microthecum +
variety +