Cytology of Some Species of Sansevieria Thunb

抄録

Fifteen species of Sansevieria have been studied cytologically, of which 11 are diploids, 1 tetraploid, 2 hexaploids and one aneuploid. The chromosome number of 4 species has been reported for the first time, together with intraspecific polyploidy in one species. The karyotype is characterised by the presence of small chromosomes, and are not amenable to detailed analysis. Meiosis in diploid taxa was regular with the formation of 20 bivalents. A natural triploid was located for the first time in a clone of a diploid species, and is autoploid in nature. In higher levels of ploidy, predominant bivalent formation was noted. The genus is based on x=20 and hybridisation coupled with polyploidy seems to have played an important role in the evolution of the genus. The polyploids have arisen principally through segmental alloploidy.