Poinsettia is a genus of shrubs from the milkweed family (Euphorbiaceae) which – before you close this article – we grow as a plant known as “Christmas star”. This decoration for Christmas, but also for the New Year, is a favorite of many, but unfortunately, people usually throw this plant in the garbage after the holidays, even though it is actually a perennial.

#1 Fact: How the Poinsettia Got Its Name

Poinsettia – Christmas star, hides several interesting things. This is a plant that grows in Mexico and Central America, and Europeans first described it and gave it a scientific name in 1884. It was described as a new species by the German scientist Johann Friedrich Klotzsch. The holotype of the species was collected in Mexico during the 1803-1804 expedition, led by Alexander von Humboldt and Aimé Bonpland. Otherwise, a holotype is a unique specimen of an organism that has been used to describe a species.

First, why is the scientific name of the plant so strange? This is not the scientific name of the plant as we might think. The scientific name is Euphorbia pulcherrima, which would mean “the most beautiful milkweed”. Pulcherrima is a superlative adjective in the feminine gender – beautiful (pulchra), more beautiful, superlative – the most beautiful. After this short reminder of everyone’s favorite Latin from high school, let’s get back to more serious topics – the name poinsettia.

Poinsettia is the name given to the plant in honor of Joel Roberts Poinsett, the first US ambassador to Mexico. In addition to being a diplomat, Poinsett was also a physician and botanist. Before Mexico, he toured Europe, the Ottoman Empire, Russia, Transcaucasia, Chile and Argentina. By the way, he was also a co-founder of the National Institute for the Promotion of Science and the Useful Arts, which is the origin of the Smithsonian Institution. As a diplomat in Mexico, he was in charge of the American acquisition of some Mexican territories, such as today’s New Mexico, Texas, even parts of California and Sonora, and the creation of the Mexican-American border.

After visiting an area south of Mexico City near Taxco de Alarcón, Poinsett saw this plant. By the way, in Mexico it is called Flor de Nochebuena, the flower of Christmas or Catarina. Poinsett, a passionate amateur botanist, sent samples of the plant to the United States, and by 1836 the plant was already widely known as “poinsettia”. This is how the plant began to spread as an ornamental in the USA and beyond.

#2 Fact: The Flowers Are Not What You Think

The red poinsettia flowers are not actually flowers – the flowers themselves are very unsightly and are located in the middle of the red bract. Red is actually modified leaves, bracts. Besides red, they can be in pink, orange, beige and white.

Bract colors are produced by photoperiodism, meaning they require darkness (at least fourteen consecutive hours over 6–8 weeks) to change color. Plants also require abundant light during the day. So first they need darkness to change to red, but they also need light. Who would please them. They are semi-evergreen, they usually lose most of their leaves during the winter, which is why people throw them away when they lose their leaves.

#3 Fact: Chemical Composition

As this is a plant from the milkweed family, it also secretes white juice. Pulherol and pulheryl acetate are among the ingredients of that juice, or latex. Triterpenes are found in the aerial parts of this plant, including the milky sap and leaves. One of the triterpenoid compounds is being investigated as a basis for drugs against Alzheimer’s disease. In addition, the plant contains anthocyanins, which are responsible for the red color of the bracts.

#4 Fact – It Is Mildly Toxic, but Not Deadly

Milkweeds are usually toxic, but this one is not fatally poisonous. In fact, it is not poisonous at all and tests on rats did not show that this plant is poisonous, but yes – it can cause itching, redness and swelling and allergies in some people.

#5 Fact: It Is Rare in the Wild

Although this plant can be bought on almost every corner during the winter, before the holidays, it is endangered in its natural habitat and there are not many specimens. The greatest risk for the conservation of this species in the wild is the possibility that the wild hybridizes with the cultivated.

#6 Fact – It Can Be Used as a pH Indicator

Poinsettias are excellent plants for indicating the pH value of a liquid because they contain anthocyanin pigments that are very sensitive to changes in acidity. Anthocyanin is the substance that gives the red color to the poinsettia leaves and makes the poinsettia indicator solution red. You can make this pH indicator in a similar way to the red cabbage one – slice the red poinsettia leaves and pour boiling water over them. When the leaves release color into the water, strain and you’ve got your indicator, which you can test with a solution of vinegar, citric acid, baking soda and detergent.

In an acidic environment below pH 3, the solution will be red. But, as the pH value increases towards the basic one, the solution first becomes colorless (pH3-4), then purple (pH 4-7, slightly acidic to neutral), then blue (pH 7-8), while above 8 it is greenish. Have fun with these experiments!