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A uniquely high level of anoxia tolerance has been observed in Spitsbergen populations of some common high arctic vascular plant species. The most surprising aspect of anoxia tolerance in these species is their ability to maintain turgid, green leaves throughout the period of anoxia and into the postanoxic recovery phase. Prolonged anoxia tolerance has never been reported previously for green leaves, which normally lose turgor and wither rapidly when deprived of oxygen. Tests on more southern populations from Norway, Iceland, and Scotland of species found to be tolerant of anoxia in Spitsbergen failed to detect an equivalent ability to survive oxygen deprivation. This distinctive feature of high arctic populations as compared to more southern populations of the same species suggests a different evolutionary history for arctic populations as compared with those from lower latitudes. Possession of a such an unusual physiological feature whole-plant anoxia tolerance, not found in more southerly populations, is an additional argument for suggesting that some arctic populations of vascular plants may have survived part of the Pleistocene epoch at high latitudes in ice-free polar deserts. Such populations will have been exposed to many climatic alterations in the past and this history of a long-term presence in the High Arctic is discussed in relation to current threats to arctic vegetation from climatic warming.