Plant Diversity

Early Plants

Why is an extinct plant called Cooksonia important?

To date, an extinct plant called Cooksonia—named for paleobotanist Isabel Cookson (1893–1973)—is important to understanding how plants eventually evolved on land. The first fossils of these macroscopic land plants were found in the Silurian period in Ireland and are about 425 million years old. The plant was very small (not even an inch high) and simple. It had a bifurcated (branched) stem topped with small spheres in which the spores formed; it also had water-conducting cells in the stems, but no roots or leaves. It is thought that this tiny organism spread in humid places on land and may be the ancestor of the flowers in your gardens.


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