The poinsettia, known to botanists as Euphorbia pulcherrima, is a shrub native to Mexico and Central America, whose festive look has made it a worldwide seasonal decoration. The plant’s common name comes from Joel Roberts Poinsett, who introduced it to the United States in the 1820s. Its unique structure is often mistaken for a typical flower.
Defining the Poinsettia’s Colorful Structure
What most people admire as the poinsettia’s petals are actually specialized leaves called bracts. These structures grow at the top of the plant, surrounding the true, inconspicuous flowers. The bracts are commonly a flaming red color, but modern cultivars have been bred to display shades of pink, white, cream, orange, or even marbled patterns.
The purpose of the bracts is to function as a visual attractant for pollinators. Because the actual flowers are small, the brightly colored bracts evolved to lure insects and birds to the plant’s reproductive center. This color change is triggered by photoperiodism, requiring extended darkness, typically around 14 hours each night for several weeks, to develop the vibrant hues.
The Variability of Bract Count
There is no single fixed number for how many bracts a poinsettia will have, as the count depends on several factors. The specific variety, or cultivar, of the plant is a major determinant, as breeders select for density and size. The plant’s overall health and maturity also play a significant role in the final count.
Horticultural research suggests that a healthy, mature inflorescence—the entire flowering structure—can develop a consistent number of bracts under ideal commercial growing conditions. For example, studies on certain cultivars note the development of approximately 27 bracts during the full growth cycle. The number visible to the average consumer usually refers to the major colored leaves clustered around the center, typically between 8 and 20 prominent, fully colored bracts on a typical potted plant.
The number of bracts can be influenced by environmental controls during cultivation, such as night-time temperature and the duration of the dark period. Reducing night temperatures during flower initiation, for instance, can sometimes result in fewer bracts developing. This demonstrates that the final number is a combination of genetics and growing management.
Locating the True Poinsettia Flower
The actual flowers of the poinsettia are tucked away inside the cluster of colored bracts and are called cyathia. These are small, cup-shaped structures, typically yellowish-green, which form the plant’s true reproductive organs. A prominent feature of the cyathia is the presence of specialized nectar glands, which are visible as yellow or orange structures on the rim of the cup. These glands produce nectar to reward the pollinators attracted by the showy bracts. The true flowers are unisexual, meaning they contain either male or female parts, and are clustered together within the cyathium to mimic a single, conventional flower.