CHROMOSOME CYTOLOGY AND KARYOTYPE CHANGE IN GALAXIA (IRIDACEAE)

Basic chromosome number in Galaxia is believed to be x = 9, and this number, or multiples, occurs in all species of subgenus Galaxia. In subgenus Eurystigma, G. barnardii has n = 8, G. versicolor n = 8 and 7, G. citrina n = 8, 7 and 17 while G. variabilis has n = 7 exclusively. Karyotypes in forms of G. versicolor with n = 7 and in G. variabilis are quite different and clearly originated independently. Karyotypic features provide evidence for the hypothesis that changes in chromosome number were accomplished through chromosome fusion either by classical Robertsonian translocation, or unequal reciprocal translocation. © 1979 Springer-Verlag.