| 1. Phyllaries oblong, tips blunt to rounded, green < 1/4 total length of phyllary, often swollen and wart-like |
| I. acradenia |
| 2. Leaves conspicuously reduced upward, grading into bracts below heads, these grading into phyllaries; flowers 1017 |
| var. bracteosa |
| 2' Leaves uniform throughout, or only slightly reduced upward, not grading into bracts below heads; flowers 614 |
| |
| 3. Leaves narrowly oblanceolate, entire; involucres 45 mm |
| var. acradenia |
| 3' Leaves narrowly obovate, with long-tapering base, to obovate, with 46 teeth per side; involucres 57 mm |
| var. eremophila |
| 1' Phyllaries lanceolate, tips acute to acuminate, green 1/31/2 total length of phyllary, flat |
| |
| 4. Involucres 4.57 mm, 2.55 mm diam; upper stems yellow-white |
| I. arguta |
| 4' Involucres 810 mm, 58 mm diam; upper stems gray, green, tan, or red |
| I. menziesii |
| 5. Plant prostrate; leaves widely obovate with a long-tapering base, margins toothed, fleshy; exposed areas on beaches, dunes, sea-cliffs |
| var. sedoides |
| 5' Plant decumbent to erect; leaves linear, (ob)ovate or narrowly spoon-shaped, not fleshy; inland, or protected areas on coast |
| |
| 6. Stems scabrous to tomentose; leaves generally not clustered in axils, green to gray-green, not closely spaced; stem readily visible |
| var. menziesii |
| 6' Stems glabrous to scabrous; leaves clustered, dark green, often so closely spaced that the stem is obscured |
| var. vernonioides
|