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
Plant development roots and buds are very important when people propagate plants via cuttings, layering, tissue culture. Plant hormones, termed auxins, are often applied to stem, shoot or leaf cuttings to promote adventitious root formation, e.g. African violet and sedum leaves and shoots of poinsettia and coleus. Propagation via root cuttings requires adventitious bud formation, e.g. in horseradish and apple. In layering, adventitious roots are formed on aerial stems before the stem section is removed to make a new plant. Large houseplants are often propagated by air layering. Adventitious roots and buds must develop in tissue culture propagation of plants. The genetics