There are several onion species occurring within and near the range of Allium aaseae. Allium aaseae is most likely to be confused with A. simillimum, especially at mid-elevations in the Boise Foothills, where their distributions nearly overlap. Populations with purple-mottled anthers may actually be hybrids between the two species. The following key, adopted from McNeal's (1993) key to the onions of southwestern Idaho, can be used to distinguish the two:
Allium simillimum. Perianth segments white with green or reddish midveins, sometimes flushed with pink; anthers purple or mottled purple and white, pollen white or grayish; denticulations, particularly on the inner perianth segments obvious under a hand lens and regularly distributed on the distal 2/3 of the segment; occurring above 4200 feet elevation on various substrates.
Allium aaseae. Perianth segments bright pink with rarely a white individual in an otherwise pink population; anthers yellow, pollen yellow, denticulations +/- irregular in number and distribution on perianth segments, often missing on plants from Rebecca Sand Hills RNA; usually restricted to lacustrine sands of the Glenns Ferry Formation, generally below 3700 ft., except in Cartwright Canyon where occurring up to 5100 ft. elevation.