Eriogonum arcuatum

Herbs, spreading to often compact mats, 0.2–2.5 × 2–10 dm, floccose. Stems: caudex absent or spreading; aerial flowering stems erect or nearly so, slender, solid, not fistulose, usually arising directly from a taproot, 0.2–2 dm, floccose. Leaves basal, typically not in rosettes; petiole 0.5–2 cm, tomentose to floccose; blade oblanceolate or oblong to elliptic, 0.5–3 × 0.5–1.5 cm, densely tomentose abaxially, mostly floccose and grayish or greenish adaxially, margins entire, plane. Inflorescences umbellate or compound-umbellate, occasionally capitate or even reduced to single involucre, 0.3–2 × 0.3–2 dm; branches floccose; bracts 3–8, semileaflike at proximal node, 0.3–2 × 0.2–1 cm, often scalelike distally. Involucres 1 per node, usually campanulate, 3–7 × 3–8 mm, floccose; teeth 5–8, erect, 0.1–0.5 mm. Flowers 4–8 mm, including 0.7–2 mm stipelike base; perianth yellow, densely pubescent abaxially; tepals dimorphic, those of outer whorl lanceolate to elliptic, 1.5–5 × 1–3 mm, those of inner whorl lanceolate to fan-shaped, 1.5–7 × 2–4 mm; stamens exserted, 2–4 mm; filaments pilose proximally. Achenes light brown to brown, 4–5 mm, glabrous except for sparsely pubescent beak.

Distribution

• Generated Map
• Legacy Map

w United States.

Discussion

Varieties 3 (3 in the flora).

Eriogonum arcuatum has long been included under E. jamesii, primarily as the var. flavescens. It has also gone under the name E. bakeri, published by Greene about six weeks after he published E. arcuatum; the Fort Collins, Colorado, entomologist and botanist Charles Fuller Baker collected the types of both.

Selected References

None.

Lower Taxa

Eriogonum arcuatum var. arcuatum, Eriogonum arcuatum var. rupicola, Eriogonum arcuatum var. xanthum

Key

1	Involucres (3-)4-8 mm wide; inflorescences umbellate or compound-umbellate, rarely capitate; flowers (4-)5-8 mm; below 3000 m; n Arizona, c and w Colorado, nw New Mexico, e Utah, se Wyoming	Eriogonum arcuatum var. arcuatum
1	Involucres 3-5 mm wide; inflorescences capitate, rarely umbellate or reduced to single involucre; flowers 4-5(-6) mm or 6-7 mm; usually above 3000 m in c Colorado, or 1600-1900 m in sw Utah	> 2
2	Flowers 4-5(-6) mm; Zion National Park, Utah	Eriogonum arcuatum var. rupicola
2	Flowers 6-7 mm; Rocky Mountains, Colorado	Eriogonum arcuatum var. xanthum