A closeup of a poinsettia flower cluster from the side. Many people confuse the bracts (red leaves) with the actual flowers; they're quite different. This macro shot shows multiple pseudanthia (flowering structures) surrounded by a sea of red bracts (colored leaves associated with a flower). The flowers themselves are called cyanthia; the green tissue surrounding each flower is an involucre, a cluster of bracts (leaves) fused into a cup-shaped structure that contains multiple male flowers...
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A closeup of a poinsettia flower cluster from the side. Many people confuse the bracts (red leaves) with the actual flowers; they're quite different. This macro shot shows multiple pseudanthia (flowering structures) surrounded by a sea of red bracts (colored leaves associated with a flower). The flowers themselves are called cyanthia; the green tissue surrounding each flower is an involucre, a cluster of bracts (leaves) fused into a cup-shaped structure that contains multiple male flowers and one female flower within it. Emerging from the involucre you can see red filaments supporting yellow anthers on the male flowers, and you can even see some of the pollen grains. Also emerging from each involucre you can see a number of dark-purple structures supported by short stalks (that are about a tenth of the height of the filaments; I'm not sure what these are). The bright yellow, liquid-filled structures attached to the involucre are nectar glands filled with nectar to attract pollinators.
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