In this Planet Earth podcast, Sue Nelson reports from the Royal Botanic Gardens, Kew where she finds out that some plants like the Snake's Head Fritillary have enormous amounts of DNA in their genomes. These plants struggle in extreme environments, so how will they cope under climate change? We also hear from the British Antarctic Survey's medical doctor Claire Lehman in one of our unique audio diaries. Claire joins the diving team for a refreshing dive under the Antarctic ice. Later, Sue meets a fossil-tree expert at Cardiff University. Chris Berry describes how he went about identifying the 385 million-year-old fossilised remains of trees in New York State.