水杉
The species was first described in 1863 from fossils found in the outcrops of the Late Paleocene-Middle Eocene Chuckanut Formation around Birch Bay, Washington. The species was originally described as "Taxodium occidentale" by John Strong Newberry. Fossilized "Metasequoia"-like remains were noted in Europe and North America from the 1800s on, but were assigned to the cupressaceous genera "Sequoia" (redwoods) and "Taxodium" (bald cypresses). It was not until the living species "Metasequoia glyptostroboides" was discovered and described from a remote area of China during the 1940s, that the affinity of many of the fossils became apparent. In 1951, the species was reassigned to "Metasequoia" as "M. occidentalis" by Ralph Works Chaney based on the close resemblance to living "Metasequoia". It has been said that, with few exceptions, the bulk of the fossils described in the literature indicate that "M. occidentalis" was indistinguishable from living "Metasequoia glyptostroboides".