For an extravagantly beautiful plant, poinsettia bears flowers that are often overlooked. If your holiday plant is still on display, look closely at the center of each flower-like cluster of red, white, or variegated leaves.There they are — tiny cups called cyanthia, each of which contains both male and female flowers.
The male flowers are reduced to stubby stamens, and the female flowers are star-like pistils. Also, the female flowers are mounted on pedestals that lengthen and push the flowers up and out of the cyanthium. Another characteristic of these unusual inflorescences is the glands that are found in the cyanthium.
In poinsettias, these yellow structures each produce a droplet of liquid. Flowers like this are characteristic of the Euphor biaceae family. In addition to poinsettias, castor beans, crotons, and euphorbias themselves are members of the family. It’s an economically important family, members of which produce a milky sap in their stems and leaves. Rubber trees are in this family, as is Manibot, from which we get arrowroot, starch, and tapioca. Poinsettias are poisonous, but nothing compared to castorr beans, which are the source of ricin, a highly toxic chemical that has been used as a biological warfare agent.