Poinsettia found in the center of each leaf bunch, and are called cyathia. The poinsettia is native to Mexico. It is found in the wild in deciduous tropical forests at moderate elevations from southern Sinaloa down the entire Pacific coast of Mexico to Chiapas and Guatemala. It is also found in the interior in the hot, seasonally dry forests of Guerrero, Oaxaca, and Chiapas. Reports of "E. pulcherrima" growing in the wild in Nicaragua and Costa Rica have yet to be confirmed by botanists. The Aztecs used the plant to produce red dye and as an antipyretic medication. In Nahuatl, the
Plant physiology Rather, a short day plant requires a minimal length of uninterrupted darkness in each 24-hour period (a short daylength) before floral development can begin. It has been determined experimentally that a short day plant (long night) does not flower if a flash of phytochrome activating light is used on the plant during the night. Plants make use of the phytochrome system to sense day length or photoperiod. This fact is utilized by florists and greenhouse gardeners to control and even induce flowering out of season, such as the "Poinsettia". Paradoxically, the subdiscipline of environmental physiology is on the one hand