More than 200 million years ago, Pangaea contained all the modern continents, squished up against one another. The separation of these continents isolated populations of living things, putting them on different evolutionary paths.
Scientists have already found evidence of the separation of the continents in the family histories of reptiles, amphibians and mammals.
"Until now, there has been no equivalent evidence for any plant family," writes an international team of researchers in a study published May 1 in the journal Proceedings of the National Academy of Sciences.
The cypress family, Cupressaceae, a group of conifers with scalelike leaves, is believed to have originated more than 200 million years ago, when Pangaea was still intact, according to the researchers.
By looking at changes in the DNA (deoxyribonucleic acid, the code that makes up genes) of 122 species of cypress, the researchers were able to reconstruct a timeline for their evolution. They also included fossil evidence in the analysis.