In paper published today in Nature Plants, researchers at the Royal Botanic Gardens, Kew, detail for the first time the scale of threatened species that are unable to be conserved in seed banks. The paper reveals that when looking at threatened species, 36 per cent of ‘critically endangered’ species produce recalcitrant seeds . This means they can’t tolerate the drying process and therefore cannot be frozen, the key process they need to go through to be safely ‘banked’.