New chromosome number records of South African Oxalis species
Chromosome numbers of only 49 Oxalis L. taxa have been published to date, of which just 23 represent southern African taxa. Chromosome counts for the following southern African taxa are recorded here for the first time: O. bifida Thunb., O. hirta L. var. tubiflora Salter and O. semiloba Sond. A third record for O. truncatula Jacq. is also presented here. Two previous counts for this species have been published, one revealing a tetraploid and the other a hexaploid condition. All four taxa included here have a basic chromosome number of x = 7. O. bifida and O. truncatula are both diploid, whereas O. hirta var. tubiflora and O. semiloba were both found to be tetraploid. The diploid form of O. truncatula found here completes a polyploid series (2x, 4x and 6x) in this species. It is concluded that karyological data can greatly aid our understanding of the massive diversification and speciation of Oxalis in southern Africa. Further cytological studies are recommended.