Hibiscus trionum, commonly known as Venice mallow or Flower-of-an-hour, is a small annual plant native to Australasia and now naturalised across Europe, Africa and North America. Its striking flowers display a dark purple centre with a white surround, forming a distinctive bullseye pattern. The cells in the two bullseye regions also have distinct shape and texture: the cells in the white region are smooth and conical, providing grips for pollinators while the cells in the purple region are flat and covered with microscopic striations that create a blue/UV iridescent cue, visible to pollinators. Hibiscus trionum is easy to grow and has recently been established as a model system by researchers to study petal pattern formation: its genome was recently sequenced and protocols have been developed to manipulate its genes. This species is an excellent system to study the processes that allow cells to become different from each other during development to form complex organs plant use to interact with their environment.