Plant Profile: Euphorbia heterophylla var. cyathophora

Wild Poinsettia, a member of the spurge family and a relative of the well-known Poinsettia, is a short-lived annual plant native to both North and South America. While it is grown for ornamental purposes, many consider it a weed. This plant typically thrives in disturbed environments, such as waste areas, roadsides, creek banks, and agricultural fields.

The flowers of Wild Poinsettia are found in inconspicuous clusters known as cyathia, which are cup-like structures that contain multiple flowers. Each cyathium can measure up to 1.5 inches in diameter, with individual flowers being less than 1/10 of an inch wide. Each cyathium features several male flowers and a single female flower, along with one or two kidney-shaped structures that hold nectar.

As the seed capsules mature, they burst open to disperse seeds.

The plant's common names often derive from the appearance of its upper leaves, which seem as if they have been hand-painted. The leaves are arranged oppositely at the base, alternate along most of the stem, and again opposite at the upper sections of the stems and branches. Both the leaves and stems exude a milky latex sap when damaged, and the shape of the leaves can vary significantly, with different forms appearing on the same plant.

Many herbivores tend to steer clear of Wild Poinsettia due to the irritating effects of the milky sap on their mouths and digestive systems.

In terms of pests and diseases, this plant can be quite weedy and requires considerable maintenance. All parts of Wild Poinsettia are toxic if ingested, and the milky sap released from broken leaves or stems can lead to skin irritation.