Cycads are known as ‘living fossils’ because they have remained unchanged for millions of years. Study of the fossil record reveals that these plants flourished some 280-135 million years ago. They are scientifically important because they may represent a link in the evolution from ferns to flowering plants. They have been in decline perhaps ever since the flowering plants became dominant, some 100 million years ago. Most species are now rare.
Cycads vary greatly in shape and size and grow in various climatic zones from rainforest to semi-desert. They are all rather slow-growing and, like conifers, bear their reproductive organs in cones. Male and female cones are borne on separate plants. Half of the cycad species in the Palm House are threatened in the wild.
Although all parts of cycads are toxic, they can provide a food source for some communities, particularly in times of famine. The toxins are removed by careful boiling and washing before use.