invasion of the land plants

In 1066, the Norman invasion; in 1588, the Spanish Armada. Invasion dates: What would history books and trivia games be without them? And now perhaps a new date can be added to the annals: 470,000,000 BC, the date plants invaded land. Charles H. Wellman of the University of Sheffield, UK, and his colleagues report in the Sept. 18 Nature that they have discovered fragments of the earliest land plants. Microscopic spores have previously been found in 470 million-year-old rocks, but the spores were 50 million years older than any known land plant fossils. Also, the spores were similar to those of aquatic algae, and so could not reliably be assumed to come from plants that lived on land. But the researchers have found fossilized fragments of tiny land plants holding identical spores in ancient rocks in Oman, seeming to confirm the 470 million-year date. Analysis of the fragments shows that the ancient plants were probably most similar to today’s liverworts, a moss-like plant.

This news brief appeared in the Random Data column of the Boston Globe’s Health/Science section on 9/23/2003.