Christen Christensen Raunkiær (29 March 1860 – 11 March 1938) was a Danish botanist, who was a pioneer of plant ecology. He is mainly remembered for his scheme of plant strategies to survive an unfavourable season ("life forms") and his demonstration that the relative abundance of strategies in floras largely corresponded to the Earth's climatic zones. This scheme, the Raunkiær system, is still widely used today and may be seen as a precursor of modern plant strategy schemes, e.g. J. Philip Grime's CSR system.