The structure of hellebores...

The prolonged cold weather has meant that the garden hellebores have put on a particularly long-lasting display. Normally, by early April the flowers would be fading, but this year they are all still in the peak of perfection, some two months after the first flowers appeared. Hellebores have a rather unusual flower structure, described in detail below using text from a website on hellebores.

The flower structure of hellebores is somewhat different than that of most other garden plants. Petals typically provide flower color and are often protected by a calyx in most garden plants. In hellebores, no calyx in this sense is present, and the only thing resembling petals comes in the form of tubular nectaries at the base of the sepals. These nectaries provide food for pollinators, though many pollinators are likely attracted by ultraviolet reflections by the much larger sepals. Nectaries last but a short time and are shed along with the stamens by the time carpels begin to swell with fertilized ovules.

Sepals provide the flower color and main horticultural attraction in hellebore flowers, but they function differently than do petals and are much more responsive to environmental factors. Most noticeably, the sepals remain on the flower long after fertilization and never really fall off. They simply change colours and eventually dessicate and deteriorate along with the entire inflorescence. The sepals most commonly number five and consist of two outer sepals, two inner sepals, and one that has an edge inside and outside the edges of adjacent sepals. The outer two sepals provide some protection from the elements and are often a different color than the innermost sepals, particularly after prolonged exposure to sunlight, cold, wind, and precipitation.

Sepals undergo a significant amount of photosynthetic activity compared to petals. After fertilization, photosynthetic activity usually increases in hellebore plants so that in the fruiting stage the sepals turn greener or darker green. Citokinins and gibberellins activate chloroplasts after fertilization, and this activity is later slowed in the fruiting phase. Throughout this photosynthetic process the peduncles and petioles elongate and sepals broaden and spread apart, which is believed to aid in the distribution of seed. In some plants the sepals do not turn green after fertilization, and this is most obvious in dark flowers that possess permanent anthocyanins.

The interior of the perianth consists of a cluster of stamens tightly surrounding the carpels, which in turn surrounds the pistils. Generally, the pistils are receptive to pollen before the stamens mature, which is useful for cross-pollination and is a fortunate aspect of hellebore morphology from a breeding/hybridizing perspective. As the stamens elongate the anthers begin to produce pollen. The anthers then often curve outward away from the gynoecium. Flowers are hermaphroditic and generally self-fertile, and thus do not need other plants nearby to reproduce.

Many thanks for all the lovely comments, stars and hearts for yesterday's long-tailed tit. I'm struggling to find time at the moment, and feel very negligent that commenting has almost ground to a halt. I do try and browse your journals, but often it is very late at night, when my brain's hardly in gear!