The impact of low temperatures in controlling the geographical distribution of plants

Abstract The distribution limits of three species, in the British Isles are discussed. For Verbena officinalis and Tilia cordata low temperatures are shown to influence distribution, by limiting the capacity either to flower or to fertilize ovules, respectively. In the case of Umbilicus rupestris, a long-term transplant population beyond the natural geographical limit of the species has evolved new low-temperature responses of seed germination and winter survival. The effect is a marked change of phenology, compared with populations of the species within its natural range, which enhances the capacity of the population to survive in a colder environment.