The flower is called Marvel-of-Peru , or Beauty-of-the-Night (Mirabilis jalapa) ornamental perennial plant, of the family Nyctaginaceae, native to tropical America. Four-o’clock is a quick-growing species up to one metre (three feet) tall, with oval leaves on short leafstalks. The stems are swollen at the joints. The plant is called four-o’clock because its flowers, from white and yellow to shades of pink and red, sometimes streaked… open at 4 o clock unless the weather is overcast which fools them into thinking it’s late and they open. They are also beautifully scented.