campion), an Arctic flower native to Siberia. The plants were not grown from seeds, which were not viable, but the placenta tissue of three fruits. Radiocarbon dating has confirmed an age of 31,800 ±300 years for the seeds. In 2007, more than 600,000 frozen mature and immature seeds were found buried in 70 squirrel hibernation burrows below the permafrost near the banks of the Kolyma River. The Arctic ground squirrels (Urocitellus parryii) believed to have buried the seeds had damaged the mature seeds to prevent germination in the burrow, but three of the immature seeds contained viable placenta tissue, which was successfully grown in vitro. The plants grew, flowered and created viable seeds of their own. The shape of the flowers differed from that of modern S. stenophylla with the petals being longer and more widely spaced than modern versions of the plant. Seeds produced by the regenerated plants germinated at a 100% success rate, compared with 90% for modern plants. Calculations of the γ radiation dose accumulated by the seeds since burial gave a reading of 0.07 kGy, the highest maximal dose recorded for seeds. See also Longevity List of oldest trees Orthodox seed Seed bank References Seeds Oldest things