snapdragon
Many plants depend so heavily on visits from bees that they go to great lengths to attract them, using brightly coloured flowers baited with sweet nectar. But some of their tricks are much subtler and are designed not to attract six-legged visitors, but to make their stay more convenient.
The majority of flowering plants have evolved special conical cells that line the surface of their petals and are found nowhere else. These cells provide the flower with a rougher texture that is indistinguishable to human fingers, but that provide just enough purchase for the claws of landing insects.…