Pittonia 3: 265. 1898.
Perennials, 2–30+ cm. Caudices ± branched, branches notably thickened distally. Stems 1–35(–60), erect, unbranched. Leaves all basal, new leaves tightly clustered; blades spatulate or oblanceolate to linear-oblanceolate, entire, glabrous or ± hairy, often lanuginose, sericeous, or strigoso-canescent, eglandular or ± gland-dotted. Heads 1–35(–60) per plant, borne singly. Peduncles 0.5–30 cm, ± hairy. Involucres 7–12 × 8–16 mm. Outer phyllaries 6–12, 3.9–9(–11.5) mm, margins 0–0.4 mm wide, sometimes slightly scarious, abaxial faces ± hairy. Ray florets 8–15(–21); corollas 9–19 mm. Disc florets 25–200+; corollas yellow, 2.7–4.3 mm. Cypselae 2–4 mm; pappi of 5–8 obovate to oblanceolate, aristate scales 2.2–3.7 mm.
Alta., Sask., Ariz., Calif., Colo., Idaho, Kans., Mont., N.Dak., N.Mex., Nebr., Nev., Okla., S.Dak., Tex., Utah, Wyo.
Varieties 4 (4 in the flora).
|1||Leaves sparsely to densely hairy, often lanuginose, sometimes sericeous, not strigoso-canescent; peduncles 0.5–8(–12) cm; outer phyllaries 6.8–9(–11.5) mm; growing at (2100–)3000–3900 m||Tetraneuris acaulis var. caespitosa|
|1||Leaves sparsely to densely hairy, often strigoso-canescent; peduncles (1–)5–20(–30) cm; outer phyllaries 4–7.5 mm; growing at 700–2900(–3500) m||> 2|
|2||Leaf blades usually densely, sometimes sparsely, strigoso-canescent; e of continental divide (except for 2 reports from nw Idaho)||Tetraneuris acaulis var. acaulis|
|2||Leaf blades glabrous or sparsely to moderately to sometimes densely hairy, not strigoso-canescent; w of continental divide||> 3|
|3||Leaf blades glabrous or usually sparsely to moderately or sometimes densely hairy, densely gland-dotted; n Arizona, se California, w Colorado, s Idaho, e Nevada, Utah||Tetraneuris acaulis var. arizonica|
|3||Leaf blades glabrous or sparsely to moderately hairy, at least some (usually most or all) eglandular or sparsely gland-dotted; w Colorado, c, ne Utah, and sw Wyoming||Tetraneuris acaulis var. epunctata|