1a. Agoseris glauca (Pursh) Rafinesque var. glauca
Agoseris lacera Greene; A. lapathifolia Greene; A. longissima Greene; A. longula Greene; A. microdonta Greene; A. procera Greene; A. vicinalis Greene
Leaf blades: margins ± straight, usually entire (most) to dentate, sometimes irregularly so, faces glabrous and glaucous, sometimes sparsely hairy. Peduncles usually glabrous, sometimes apically puberulent, eglandular. Involucres obconic to campanulate. Phyllaries usually green, sometimes medially rose-purple, often purple-black spotted and/or tipped, faces usually glabrous, sometimes proximally puberulent, margins ± straight, glabrous (most) or proximally puberulent; outer erect or spreading, usually abaxially glabrous (most). Receptacles epaleate. Cypselae usually scabrous distally, sometimes glabrous. 2n = 18.
Flowering May–Sep. Wet meadows, stream margins, swales, other moist sites, grasslands, steppes, and meadow habitats, slightly alkaline or saline sites, mostly in silts, clays, and other fine-textured soils; 100–2500(–3300) m; Alta., B.C., Man., Ont., Sask.; Ariz., Calif., Colo., Idaho, Mich., Minn., Mont., Nev., N.Mex., N.Dak., Oreg., S.Dak., Utah, Wash., Wyo.
Variety glauca is usually found at lower elevations from the northern prairies westward to valleys and basins of the North American cordillera. Misidentification is often due to falsely assuming this variety is strictly glabrous. Some regional phases have a high percentage of individuals with weakly puberulent peduncles and/or phyllaries. In addition, var. glauca intergrades with var. dasycephala in some locations.
Hybrids between var. glauca and other Agoseris species occur. Two have been described (as species). Agoseris glauca var. glauca × A. parviflora (= Agoseris ×agrestis Osterhout) occurs frequently in the foothills of the Rocky Mountains of Colorado. This is the basis for A. glauca var. agrestis (Osterhout) Q. Jones, a name that has been widely but mistakenly applied to many specimens of A. glauca var. dasycephala. Agoseris glauca var. glauca × A. monticola (= A. ×dasycarpa Greene) is found primarily on the Modoc Plateau of northeastern California and adjacent Oregon.