Poinsettias produce colourful leaves called bracts, while the actual flowers are the small yellow centres.

The longer version

The showy red parts of a poinsettia are modified leaves called bracts. They surround a cluster of small structures in the middle, and those are the actual flowers, each reduced to little more than the parts needed to produce pollen and seed.

Colour change is triggered by day length. As nights grow longer, the plant stops making chlorophyll in the upper leaves and builds other pigments instead, turning them red, pink, or white. The bracts act as a signal to insects, since the true flowers are far too small to attract attention on their own.

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Plants and Trees gathers ordinary and surprising details about how green things live, from the tallest forest giants down to the moss on a garden wall. Expect notes on flowers, seeds, roots, leaves, fungi, and the quiet tricks plants use to spread and survive. The full list sits on the Plants and Trees page, where every entry is listed in order.

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