Cytology of Oxalidaceae

Abstract

1. Chromosome numbers of five species of Oxalis, one species of Biophytum and two of Averrhoa jave beem determined from pollen mother cells during meiosis. They are n=24 in Oxalis pubescens and O. corniculata, n=14 in O. pes-caprae and O. violacea, n=28 in 0. teti-apIlylla, n=9 in Biophytum sensitivum, and n=11 in Averrhoa bilimbi and A. carambola.
2. All the species of Oxalis studied were polyploids on the basic numbers 6 and 7. From a review of all the cytological data on the genus it is seen that 5, 6, 7, 9 and 11. are the basic chromosome numbers in Oxalis, 7 being the most frequently occurring number. Biophytum and Averrhoa have 9 and 11 respectively as their basic numbers.
3. Affinities of the family are briefly considered in the light of cytological findings. Oxalidaceae is suggested to be more closely related to Geraniaceae.
4. Polyploidy, side by side with considerable change of basic chromosome numbers, is suggested to have been responsible for the evolution of a large number of species in Oxalis, while polyploidy and change of basic numbers are absent in Averrhoa.