Hello, sunshine

Each fossil we uncover reveals another chapter in the story of life on Earth. In an extract from his new book, A History of Plants in 50 Fossils, palaeobotanist Paul Kenrick examines a 47 million-year-old member of the sunflower family, Raiguenrayun cura

- Paul Kenrick

THIS brush-shaped fossil is the oldest known member of the daisy or sunflower family. Its colour and texture capture something of the feel of Vincent van Gogh’s famous paintings of the dying sunflowers, which were built up from thick ochre-coloured brushstrokes invoking the texture of petals and seed heads.

The sunflower is distinctive and unusual because what appears to be a single flower actually is a composite of numerous, simple flowers of varied shapes that are grouped together at the end of a stem, collectively acting as a single integrated entity. This compound flowerhead gives the family its name Compositae and also its alternative name Asteraceae, which comes from the classical Latin word aster, meaning ‘star’. Nearly 10% of the flowers in the world today belong to this family. With 27,400 species, the Asteraceae is second only to the orchids in size, yet measured against the long history of plant evolution, the rise of the sunflowers is a comparatively late phenomenon.

The Asteraceae are thought to originate in southern South America about 70 million years ago, close to the dawn of the Cenozoic Era. In this small corner of the world the new young family survived the catastrophic environmental change that led to the extinction of the dinosaurs, and the earliest stages of their evolution would have taken place in the immediate aftermath, as ecosystems began to recover. Some 20 million years later their numbers and diversity had grown, and they dispersed across the ever-widening southern Atlantic Ocean to Africa, and from there onwards to Europe and Asia, arriving in North America some 30 million years ago.