CYTOGEOGRAPHICAL STUDY OF CALYCANTHUS LINNEUS
Li, Lin Chu (Department of Biology, Fudan University, Shanghai)
The present paper deals with the karyotype analysis of Calycanthus oc-cidentalis Hooker et Arnott. The karyotypic formula is K(2n)=22=2Cm (2SAT) +2sm for the first time, which belongs to "2A" type of Stebbins' as the same as C. flo-ridus var. oblongifolius . These karyotypes are more advanced than that of C. chi-nensis ("lA"  ) and sequence of them from primitive to advanced may be C. chinesislllllllllllllll C. occidentalisllllllllllllll C. floridus (var. oblongifolius). The author suggested thatgenera Calyconthus might originate from Eastern Asia (China) by C. chinensis and then form C. occidentalis and C. floridus (var. oblongifolius) after migrating eastward into North America.