Euphorbia subg. Poinsettia Euphorbia subg. Poinsettia Euphorbia" subg. "Poinsettia is a subgenus deriving from the genus "Euphorbia", and is endemic to North America. <nowiki> </nowiki>It contains around 24 species, of which the best known is "E. pulcherrima", the poinsettia. This species grows wild in the mountains on the Pacific slope of Mexico, and despite many legends, no one is quite sure from which wild populations the cultivated varieties derive. This taxon was first published at genus rank under the name Poinsettia by Robert Graham in 1836. It was demoted to a section of "Euphorbia" as E." sect. "Poinsettia by Henri Ernest Baillon in
Poinsettia length. The colored bracts—which are most often flaming red but can be orange, pale green, cream, pink, white, or marbled—are often mistaken for flower petals because of their groupings and colors, but are actually leaves. The colors of the bracts are created through photoperiodism, meaning that they require darkness (12 hours at a time for at least five days in a row) to change color. At the same time, the plants require abundant light during the day for the brightest color. The flowers of the poinsettia are unassuming and do not attract pollinators. They are grouped within small yellow structures