The HANDSTAND October Issue 2010

Scientists have found the oldest known land plants, a discovery that pushes the colonization of land by plants back to 472 million years ago. According to a report published in the New Phytologist, the newly found plants are liverworts, very simple with no stems or roots. Researchers from the Department of Paleontology at the Argentine Institute of Snow, Ice and Environmental Research in Mendoza, collected samples of sediment from the Rio Capillas in northwest Argentina and processed them by dissolving them in strong acids. Led by Claudia Rubinstein, the team found hardy fossilized spores from five different types of liverwort, which is known as a primitive plant and said to have evolved from freshwater multi-cellular green algae. "Spores of liverworts are very simple and are called cryptospores," Dr Rubinstein told the BBC. "The cryptospores that we describe are the earliest to date." The spores which date back to between 473 and 471 million years ago come from plants belonging to five different groups of species. "That shows plants had already begun to diversify, meaning they must have colonized land earlier than our dated samples," Dr Rubinstein explained. The discovery surprised many scientists as it took place at least 5000km, from the Saudi Arabia and the Czech Republic, where previous earliest traces of land plants, small liverwort cryptospores, were found. TE/MGH
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