So she told him all about the flowers, how some grew very slowly and others bloomed in a night; how clever the convolvulus was at climbing, and how shy violets were, and why honeycups had folded petals. —Max Beerbohm, The Happy Hypocrite, 1897
Not in OED as a plant name. It does refer to Zenobia pulverentula, but this is not native, so I doubt that Max meant that one. An obscure folk name? I can't find it qua plant name on Google Books either.