Influence of varying temperatures i.e. 31°C, 44.4°C, and 36°C on the:behaviour of chromosomes was studied in the pollen mother cells (pmcs) and embryo-sac mother cells (ernes) ofCrotalaria junceaL. While meiosis in both the sex cells at 31°C was normal with perfect bivalent formation observed in cells at diplotene/diakinesis and metaphase-I stages, abnormal meiosis, characterized by the failure of synapsed chromosomes to retain chiasmata at diakinesis and later stages resulting in the formation of varying frequencies of univalents, was a common fea ture at 44.4°C. Interestingly, the felling apart of homologues was found to be spe- ; cific to microsporogenesis and megasporogenesis showed normal synapsis. However, with a subsequent fall in temperature to 36°C, all the pmcs restored their normal pairing behaviour. The possible causes of such differential behaviour of chromosomes in the two sex cells and its significance is discussed.