The earliest plants to have colonised land have been found in Argentina. The discovery puts back by 10 million years the colonisation of land by plants, and suggests that a diversity of land plants had evolved by 472 million years ago.
The newly found plants are liverworts, very simple plants that lack stems or roots, scientists report in the journal the New Phytologist. That confirms liverworts are likely to be the ancestors of all land plants.
The appearance of plants that live on land is among the most important evolutionary breakthroughs in Earth's history. Land plants changed climates around the globe, altered soils and allowed all other multi-cellular life to evolve and invade almost all of the continental land masses.
The discovery of the oldest known land plants was made by a team of researchers led by Claudia Rubinstein of the Department of Palaeontology at the Argentine Institute of Snow, Ice and Environmental Research in Mendoza, Argentina.
She and her collected samples of sediment from the Rio Capillas, in the Sierras Subandinas in the Central Andean Basin of northwest Argentina. They then processed the sediment samples by dissolving them in strong acids, taking great care to avoid contamination.