Why are flowers not black in colour?

There is a lot of physics and chemistry involved in flowering and colouration of flowers. Visual and chemical stimuli are provided by the flowers to the pollinators like bees. Flowers have to be essentially in colours other than black. Black objects absorb and retain heat. Hence, flowers, if black, will wither soon after sunrise. Essentially the pollen will have to be kept cool during daytime, at least for 8 hours for viable pollination. Since most of the flowers directly face the sun at least for a few hours, stresses like rise in temperature, photosynthetic oxygen surge and fluid rise due to capillary pressure will adversely affect the texture, composition and longevity of flowers. That is why flowers are not black in colour. It is a natural adaptation.