FOUR-O'CLOCK

[four-o'clock] n (1756): any of a genus (Mirabilis) of chiefly American annual or perennial herbs (family Nyctaginaceae, the four-o'clock family) having apetalous flowers with a showy involucre simulating a calyx; esp: a garden plant (M. jalapa) with fragrant yellow, red, or white flowers opening late in the afternoon