Foxglove leaf. Coloured scanning electron micrograph (SEM) of a section through a leaf from a foxglove (Digitalis purpurea) plant, showing its hairs (trichomes). The long hairs are a physical defence against animals that might want to eat the plant's leaves, whilst the glandular hairs (yellow) release highly toxic chemicals when touched. Magnification: x107 when printed at 10 centimetres wide.