Cladistics and Biogeography of Artemisia sect. Viscidipubes and sect. Albiraotea (Compositae)

Twenty-six species and eight varieties of Sect．Viscidipubes & Sect．Albibractea are endemic to Asia．Most species of Sect．Viscidipubes are distributed from low to high altitudes and cold areas in the Hengduan-Himalayan Mountains，with only a few species extending to E or S Asia．Sect．Albibractea is distributed mainly in the subtropics and tropics，lower altitudes and moist areas in S & SE Asia，with a few species extending to the Qinling range of China．Both sections are more advanced than the other sections．They were studied by cladistic analysis and outgroup comparison．Data matrix of 55 characters from stems，leaves，inflorescences，female flowers，bisexual flowers，achenes，pollen grains and chemical constitution was employed in separate and combined studies．Eighteen most parsimonious cladograms were generated with 358 steps，consistency index of 0．72 and retention index of 0．87． 1．Within Artemisia，Sect．Viscidipubes and Sect．Albibractea are sister groups to all the other groups． 2．We support the idea to separate Sect．Viscidipubes (incl．Ser．Viscidipubes，Ser．Erlangshanenses and Ser. Pleiocephalea) and Sect．Albibractea (incl．Ser．Albibractea，Ser．Flaccidae and Ser. Anomalae)．The authors suggest that Ser．Anomalae include A．deversa and Ser．Erlangshanenses include A．zayuensis and A．yadongensis as well as Ser．Viscidipubes include A．gyitangensis and A．boreali-siamensis．As the result of the cladistic analysis，the authors tend to propose a new series， Ser．Tanguticae，incl．A．tangutica in the section．3．We consider that SW China，especially W Sichuan，is the speciation center and the tration of the present distribution center．4．A．boreali-siamensis，only in N Thailand，is not related to the widely distributed species in Ser．Pleiocephalae，such as A．atrovirens，A．chingii and A．myriantha，but rather closely related to species，such as A．vexans，A．occidentali-sichuanensis,which are endemic to W.Sichuan and E．Xizang．