Eriogonum thompsoniae

S. Watson

Amer. Naturalist 7: 302. 1873.

Synonyms: Eriogonum corymbosum var. thompsoniae (S. Watson) S. L. Welsh
Treatment appears in FNA Volume 5. Treatment on page 261. Mentioned on page 236, 237, 259.
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Herbs, spreading, not scapose, 2–5(–6) × 2–5 dm, glabrous, green. Stems spreading, without persistent leaf bases, up to 1/5 height of plant; caudex stems spreading, glabrous; aerial flowering stems erect, slender, solid, not fistulose, 1.2–3 dm, glabrous, tomentose among leaves. Leaves basal or sheathing up stem less than 2 cm, 1 per node; petiole (0.1–)3–7(–10) cm, tomentose to floccose or glabrous; blade linear or oblong to oblanceolate or elliptic, 2–8(–10) × 0.2–2.5(–3) cm, thinly to densely white-tomentose abaxially, glabrous and green adaxially, margins plane or slightly revolute. Inflorescences cymose, open, 10–30 × 10–25 cm; branches dichotomous, glabrous; bracts 3, scalelike, linear, 2–5(–7) mm. Peduncles absent. Involucres 1 per node, turbinate, 2–3(–3.5) × 1–1.5(–2) mm, glabrous; teeth 5, erect, 0.4–0.5 mm. Flowers 3–3.5 mm; perianth yellow or white, glabrous; tepals connate only at base, monomorphic, oblong to obovate; stamens slightly exserted, 3–3.5(–4) mm; filaments sparsely pilose proximally. Achenes light brown to brown, 2.5–3 mm, glabrous except for slightly papillate beak.

Discussion

Varieties 3 (3 in the flora).

Selected References

None.

Key

1 Leaf blades linear, 3-8(-10) × 0.2-0.4(-0.6) cm Eriogonum thompsoniae var. atwoodii
1 Leaf blades oblong to oblanceolate or elliptic; 2-5 × 0.8-2.5(-3) cm > 2
2 Perianths yellow Eriogonum thompsoniae var. thompsoniae
2 Perianths white Eriogonum thompsoniae var. albiflorum