Cytotaxonomy of Malvaceae

I. Chromosome number and karyotype analysis of Hibiscus, Azanza and Urena

抄録

Three genera viz. Hibiscus, Azanza and Urena are considered for the present investigation.
Of the five species of Hibiscus analysed H. panduraeformis seems to be most primitive while, H. vitifolius and H. cannabinus are slightly more advanced. H. lobatus and H. sabdariffa have medium to very short types of chromosomes and show higher ploidy levels, and thus be considered more advanced than others.
The problematic status of the genus Azanza is reviewed in the light of our findings, which ascertains the maintainance of distinct generic status and be placed inbetween Thespesia and Hibiscus.
The more evolved nature of Urena sinuata is ascertained by the presence of 2 super-numerary, secondarily constricted and satellited chromosomes in the complement. Existence of cytotypes within the circumscription of species is suspected.
Regarding the basic number for the family, it is concluded that 6 can be the basic number, found in more than one genera; and evolution must have taken place along divergent lines among the genera and species. The course of evolution within the family might be through ploidy accompanied by structural changes in different combinations.