Euphorbia subg. Poinsettia 1858, but promoted to subgenus rank by Homer Doliver House in 1924. Recent studies have confirmed its monophyly. Its many species include: The common name "wild poinsettia" is sometimes applied to two of these species. 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
Plant development forms is referred to as 'vegetative phase change', but there is some disagreement about terminology. Plant structures, including, roots, buds, and shoots, that develop in unusual locations are called "adventitious". Such structures are common in vascular plants. Adventitious roots and buds usually develop near the existing vascular tissues so they can connect to the xylem and phloem. However, the exact location varies greatly. In young stems, adventitious roots often form from parenchyma between the vascular bundles. In stems with secondary growth, adventitious roots often originate in phloem parenchyma near the vascular cambium. In stem cuttings, adventitious roots sometimes also originate