Coldest places on earth with angiosperm plant life

The highest elevation flowering plant ever recorded in Europe, a lush moss flora, one of the coldest places of permanent animal life (collembola, mites) and indications of mycorrhizal fungi were evidenced for the Dom summit (4,545 m, central Swiss Alps) between solid siliceous rock at 4,505-4,543 m, 46 degrees N. Cushions of Saxifraga oppositifolia were found at 4,505 to 4,507 m a.s.l. A large individual (possibly <30 years old) was in full bloom on 12 August 2009. The 14 C-dated oldest debris of the biggest moss, Tortula ruralis, suggests a 13 year litter turnover. The thermal conditions at this outpost of plant life were assessed with a miniature data logger. The 2008/09 growing season had 66 days with a daily mean rooting zone temperature <0 degrees C in this high elevation micro-habitat (2-3 cm below ground). The degree hours <0 degrees C during this period summed up to 4,277 degrees h corresponding to 178 degrees d (degree days), the absolute winter minimum was -20.9 degrees C and the absolute summer maximum 18.1 degrees C. The mean temperature for the growing period was +2.6 degrees C. All plant parts, including roots, experience temperatures below 0 degrees C every night, even during the warmest part of the year. On clear summer days, plants may be physiologically active for several hours, and minimum night temperatures are clearly above the freezing tolerance of Saxifraga oppositifolia in the active state. In comparison with climate data for other extreme plant habitats in the Alps, Himalayas, in the Arctic and Antarctic, these data illustrate the life conditions at what is possibly the coldest place for angiosperm plant life on earth.