| The ’plum yews’, Cephalotaxus Sieb.&Zucc. ex Endlicher, form a small genus of conifers which occurs in eastern Asia and north of the Indo-Chinese peninsula. In this paper, a taxonomic revision of the genus Cephalotaxus is presented based on taxonomic literature, herbarium specimens and field work. We conclude the genus to contain seven species:C. oliveri, C. fortunei, C. griffithii, C. alpina, C. harringtonii, C. nana and C. hainanensis. And the following five important parts was involved about taxonomy of Cephalotaxus:1. The original specific epithets of C. fortunei Hooker and C. harringtonii (Knight ex Forbes) Koch,"fortuni" and "harringtonia", have improper Latin terminations which should be corrected as "fortunei" and "harringtonii" seperately.2. The names of Cephalotaxus griffithii Hook. f.(1888) and Cephalotaxus lanceolata K. M. Feng (1975) were treated as the same taxon, and C. lanceolata K. M. Feng was regarded as new synonym of C. griffithii.3. Cephalotaxus harringtonii (Knight ex Forbes) Koch.(1839), C. drupacea Sieb.&Zucc.(1870), C. pedunculata Sieb.&Zucc.(1870), C. pedunculata Sieb.&Zucc. var. sphaeralis Masters (1884), C. mannii Hook. f.(1886), C. drupacca Sieb.&Zucc. var. sinensis Rehder&Wilson.(1914), and C. wilsoniana Hayata.(1914) was thought as the same species, The name of Cephalotaxus harringtonii (Knight ex Forbes) Koch, was effective and valid published for the first time was used as legitimate name. The other taxa were treated as new synonyms.4. We accept C. hainanensis and C. griffithii as separate species and not as synonyms of C. mannii. Also, C. harringtonii var. thailandensis was treated as a new synonym of C. hainanensis.5. Cephalotaxus drupacea Sieb.&Zucc. var. sinensis (Rehder&Wilson) f. globosa Rehder&Wilson (1914) and the later published taxa, C. latifolia W. C. Cheng&L. K. Fu ex L. K. Fu&R. R. Mill.(1999), C. harringtonii (Knight ex Forbes) Koch subsp. hokkaidoensis Silba (2007) and C. koreana Nakai (1930) were synonymized with C. nana.Also, on the bases of the continental drift, sea-floor spreading and plate tectonics theory, combined with the modern and palaeogeographic distribution (fossil evidence) of the genus Cephalotaxus, and seed morphology and route of transmission of Cephalotaxus, this paper infered that perhaps the plum views were living on the temperate region at least in the Triassic, their ancestral origin may be the sites of Eurasia and North America today, or that is to say, in the Palearctic and Nearctic of Laurasia. Perhaps due to the influence of Quaternary glaciation, those plants distributed historically in North America and Europe have become extinct.Finally, Interspecific relationships of Cephalotaxus revealed by some Chloroplast DNA sequences confirm that C. oliveri Masters is the first-branching taxon; C. griffithii Hooker and C. fortunei Hooker cluster together and are sister to C. alpina (Li) Fu and C. nana Nakai; C. griffithii Hooker, C. fortunei Hooker, C. alpina (Li) Fu and C. nana Nakai cluster together and are sister to C. hainanensis H. L. Li and C. harringtonii (Knight ex Forbes) Koch. |
