Isocoma bracteosa Greene, Leafl. Bot. Observ. Crit. 1: 170. 1906; Haplopappus acradenius (Greene) S. F. Blake subsp. bracteosus (Greene) H. M. Hall

Leaf blades mostly 50–150 mm, margins of proximal usually shallowly toothed, of distal entire or serrulate. Involucres 7–8 mm. Phyllary apices spinulose-aristate. Florets 20–27. 2n = 12.

Flowering Aug–Oct. Salt flats; 0–20 m; Calif.

In the limited zone of contact between vars. bracteosa and acradenia, intermediates are rare. The two differ in chromosome number and significantly in habitat (altitudes are essentially non-overlapping). Field studies may show them to warrant distinction at specific rank.