Studies on fossil Metasequoia from north-east China and their taxonomic implications

Specimens of Metasequoia from the Late Cretaceous or Early Tertiary collected from the Wuyun Formation, Jiayin County, Heilongjiang Province, north-east China, include shoots, female and male cones. Vegetative and reproductive features as well as details of leaf cuticle are described. Comparative studies on fossil and living specimens of the genus suggest a new approach to the classification of species of Metasequoia. Our investigations indicate that extant M. glyptostroboides is distinct from all of the recognized fossil species. The specimens described here, in addition to those previously regarded as M. disticha, M. japonica, M. chinensis, M. cuneata, M. papillapollenites, M. miocenica, M. kimurae, M. onukii, M. europaea, M. asiatica and M. nathorstii , are now considered to belong to a single species, namely M. occidentalis. A further valid species is M. milleri , which can be distinguished from M. occidentalis by the morphology of the male cones and the vegetative organs.