Poinsettia, or noche buena

Euphorbia pulcherrima is a shrub or small tree, typically reaching a height of 0.6 to 4 m (2 to 16 ft). The plant bears dark green dentate leaves that measure 7 to 16 cm (3 to 6 inches) in length. The colored bracts—which are most often flaming red but can be orange, pale green, cream, pink, white or marbled—are actually leaves; because the flowers are unassuming and do not attract pollinators, brightly coloured leaves developed (aka bracts). The colors come from photoperiodism, meaning that they require darkness for 12 hours at a time for at least 5 days in a row to change color. At the same time, the plants need a lot of light during the day for the brightest color.