LAND plants made their big entrance on Earth some time during the Cambrian,
tens of millions of years earlier than the fossil record had led scientists to
believe.
American researchers have found fossilised plant spores in rocks from the
Grand Canyon and Tennessee dating back to between 510 and 500 million years ago.
The oldest plant traces found before this were similar fossil spores from the
middle Ordovician, 470 million years ago. The Cambrian spores cluster in groups
of two or four, a rare feature found in primitive modern plants like the
liverwort, says geologist Paul Strother of Boston College’s…
