抄録
Distinct karyotypic differences between species of Cornus were not detected during a study of mitosis in root tip cells. C. Nuttalli was found to have 2n=22. Several interesting cytological abnormalities during microsporogenesis were evident in five species. A B chromosome was observed in several cells of C. rugosa during first division but not in second division. Globules persisted in some diakinesis cells of most Cornus species and could often be confused with chromosomes. Weak asynapsis was evident in several species. C. altornifolia, C. rugosa and C. stolonifera exhibited polyspory at the quartet stage. The result of these anomalies appears to be the generation of variability within the genus.
