While land plants have existed for about 425 million years, the first ones reproduced by a simple adaptation of their aquatic counterparts; spores. In the sea, plants -- and some animals -- can simply scatter out little living copies of themselves to float away and grow elsewhere. This is how early plants, such as the modern fern, are thought to have reproduced. But plants soon began protecting these copies to deal with drying out and other abuse which is even more likely on land than in the sea.
Unfortunately, there is no fossil evidence of exactly how flowers evolved; the evidence has them springing in advanced form into the fossil record. This was recognized almost immediately during the development of evolution theory, the strange appearance of flowers in the fossil record being called by Charles Darwin the Abominable Mystery.
Because of their varied and colorful appearance, flowers have long been a favorite subject of visual artists as well. Some of the most celebrated paintings from well-known painters are of flowers, such as Van Gogh's sunflowers series or Monet's water lilies.