Poinsettia harmful in experiments. An Ohio State University study showed no problems even with extremely large doses. Poinsettia The poinsettia ( or ) ("Euphorbia pulcherrima") (also known as "Christmas Star") is a commercially important plant species of the diverse spurge family (Euphorbiaceae). The species is indigenous to Mexico. It is particularly well known for its red and green foliage and is widely used in Christmas floral displays. It derives its common English name from Joel Roberts Poinsett, the first United States Minister to Mexico, who introduced the plant to the US in 1825. "Euphorbia pulcherrima" is a shrub or small tree,
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