Poinsettia Cyathia (Photograph by Frank Vincentz via Wikipedia Commons)
Poinsettia Cyathia (Photograph by Frank Vincentz via Wikipedia Commons)

Euphorbia pulcherrima 

The Poinsettia


Euphorbia pulcherrima possesses the following characteristics that allow it to survive and thrive in its environment:


Poinsettia Flowers (Photograph via Wikipedia Commons)




With the poinsettia's flowers being extremely reduced, chances of cross pollination would be highly unlikely without the help of its bracts. Bracts are brightly colored, modified leaves Poinsettia Flowers and Bracts (Photograph via Wikipedia Commons)(red, pink, and white most commonly) that mimic flower petals and attract pollinators such as birds and insects to the flowers. The photos to the side demonstrate the necessity for these bracts, especially in the act of pollination, by comparing the size of the flowers alone as compared to the entire plant.



Diterpene Esters

Poisoned Smiley (Image via Wikipedia Commons)Diterpene esters are the poisonous substances found in many species of Euphorbia including Euphorbia pulcherrima. The esters are irritants and cocarcinogens which can cause abdominal pain if ingested as well as skin irritation with frequent exposure and eye irritation upon contact. Although the compound is not as toxic to humans as many think, the esters do provide the poinsettia with great protection. Its presence causes the poinsettia to have few natural predators aside from humans. To learn how to care for someone experiencing problems after ingesting/contacting a poinsettia or other poisonous plant, consult the GUIDE TO POISONOUS PLANTS.



The poinsettia, like other plants and animals, has processes that occur to a daily pattern known as a Circadian Rhythm. These may include photosynthesis, flower opening, and hormone production. Additionally included is what is known as circumnutaton or the "looking for the best place of sun." Once a poinsettia senses it may not be in the best position to obtain light, and therefore perform photosynthesis, the plant will slowly but surely bend in the direction of the light. The plant is able to do so via hormones known as auxins. Auxins elongate a cell and make the cell walls on the opposite side (side not facing the sun) of the stem more elastic thereby causing bending towards the light. As mentioned, this action benefits the poinsettia by increasing the amount of photosynthetic surface area being exposed to light thus increasing the amount of life-sustaining glucose being made. To see a time-lapse video of plant circumnutation, click here. 





Website Created by Christine Vick

March/April 2009

Questions? Comments? Email me at vick.chri@students.uwlax.edu