Annual Silver Hairgrass, Silver Hairgrass, Silver Hair-grass: Aira caryophyllea var. caryophyllea (Synonyms: Aira capillaris, Aira caryophyllea, Aira caryophyllea var. capillaris, Aira elegantissima, Aira elegans ssp. ambigua, Aspris caryophyllea) - Uncommon in disturbed places east of the Cascades.
Early Hairgrass, Early Silver Hair-grass, Little Hairgrass, Spike Hairgrass, Yellow Hairgrass, Yellow Hair-grass: Aira praecox (Synonym: Aspris praecox) - Uncommon in disturbed places east of the Cascades.