Karyological Derivation of Sciadopitys verticillata Sieb. et Zucc. from a Pro-Taxodiaceous Ancestor

The lower chromosome number of Sciadopitys verticillata, 2n = 2x = 20, and the distinctive SAT-chromosomes cytotaxonomically separate this genus from the Taxodiaceae (x = 11). Paleobotanical and morphological information also indicates distinction of Sciadopitys. Karyological derivation of a 2n = 2x = 20 prototype of Sciadopitys from a 2n = 2x = 22 pro-taxodiaceous ancestor has been hypothesized. Different lines of evidence of divergence of Sciadopitys from the modern Taxodiaceae indicate separation of this species into a monotypic family Sciadopityaceae Hayata.