XVI International Botanical Congess

With the exception of Metasequoia, all other conifer genera occurring in the Clarkia flora (sites Clarkia, Emerald Creek, Oviatt Creek) are represented also in the European Neogene. Interchange of populations during the late Tertiary between Europe and North America is corroborated by identical or closely allied vicariant species of Glyptostrobus, Taxodium, and Tetraclinis among Cupressales, Cathaya (?) of the Pinales, and Amntotaxus and Taxus of the Taxales. Members of other shared genera (e.g. Cunninghamia, Calocedrus, Chamaecyparis, Pinus, Abies) stand taxonomically wider apart suggesting an earlier speciation.