Abstract
1) The male individuals of the dioecious plants comprising 11 genera, 18 species and 2 varieties have been investigated cytologically, Nith special reference to the sex chromosomes.
2) In each of 16 species and one variety one unequal pair of chromosomes was observed. This unequal pair is assumed to be a sex chromosome complex of XY type.
3) A tetrapartite chromosome was observed in Humulus lupulus var. cordifoliits, which may be a sex chromosome complex of XYXY type.
4) In Carex grallatoria and Cleratis heracleaefolia any norphological sex chromosome complex was not observed.
In ciosing the writer wishes to express his thanks to Prof. Kagawa of the Utsunomiya Agricultural College for his valuable suggestion in this work.
