This Christmas rose (Helleborus niger) was planted at New Year, already in flower. The pure white flowers were a point of light in the dark days of January. As February days got noticeably longer, the flowers set seed, dropped their conspicuous stamens and started to turn green. March has been and gone, the seed pods are swelling but the petals, now bright green, are showing no sign of fading. They’ve still got work to do.
It’s a neat adaptation. The white petals of the new flowers attract pollinating insects; once the flower has set seed, the petals turn green and start to behave like leaves, trapping sunlight and producing carbohydrates by photosynthesis, to nourish the developing seeds. Why do other plants simply drop their petals rather than putting them to good use by converting them into leaves? The difference is that, botanically speaking, hellebores don’t really have petals in the first place. By evolutionary accident, the hellebore flower is formed of sepals, the adapted leaves that protect the unopened flower buds of other species. It seems that it’s easier for a plant to ‘switch off’ production of chlorophyll in a sepal for a while, than it is to start producing it in a petal.