morning glory

or morning-glory

noun

1. any of various plants, especially of the genera Ipomoea and Convolvulus, as I. purpurea, a twining plant having cordate leaves and funnel-shaped flowers of various colors, often opening only in the morning.
2. a racehorse that runs faster in morning workouts than in afternoon races.

morning-glory

noun

1. any of various mainly tropical convolvulaceous plants of the genus Ipomoea and related genera, with trumpet-shaped blue, pink, or white flowers, which close in late afternoon

Word History and Origins

Origin of morning glory¹

An Americanism dating back to 1805–15