1c. Isocoma acradenia (Greene) Greene var. eremophila (Greene) G. L. Nesom, Phytologia. 70: 82. 1991.
Isocoma eremophila Greene, Leafl. Bot. Observ. Crit. 1: 171. 1906; Haplopappus acradenius (Greene) S. F. Blake subsp. eremophilus (Greene) H. M. Hall; Isocoma acradenia subsp. eremophila (Greene) R. M. Beauchamp
Leaf blades mostly 2.5–5 cm, margins pinnately toothed to pinnatifid. Involucres 6–8 m. Phyllary apices usually rounded, sometimes with weakly developed aristae. Florets 12–20. 2n = 12.
Flowering (May–)Aug–Nov. Sandy soils, alkaline or salt flats, desert dunes, often with Saguaro-Prosopis-Larrea, Larrea, Atriplex, Yucca, or mixed shrubs; (-15–)0–900(–1100) m; Ariz., Calif., Nev., Utah; Mexico (Baja California, Sonora).
For the most part, var. eremophila is geographically separate from var. acradenia. In southwestern Nevada many intergrades occur; in San Bernadino County, California, the two taxa appear to be contiguous with little or no intergradation. In the latter area, the taxa apparently are at different ploidy levels.