WordNet sense 1 (perennial of the eastern United States having early solitary yellow flowers followed by late petalless flowers; so-called because ice crystals form on it during first frosts):

frost-weed, frostwort, Crocanthemum canadensei, Helianthemum canadense

WordNet sense 2 (tall perennial herb having clusters of white flowers; the eastern United States):

Virginia crownbeard, Verbesina virginica