Chromosomes of fossilized Metasequoia from early Oligocene of Siberia

Abstract We visualized the Feulgen-stained nuclei and chromosomes of fossilized leaves of Metasequoia occidentalis (syn. M. disticha) from West Siberia dated to 29–33 million years old. There are about 22 metacentric chromosomes in somatic anaphase cells. The karyotype of the fossil plant is similar to the modern species M. glyptostroboides. Metasequoia was widespread in middle and high latitudes of Eurasia and North America during the Cretaceous but is represented nowadays by the single relict species, M. glyptostroboides, in central China.