抄録
Following after the previous I to III reports, several new polyploid flower plants induced by colchicine treatment in 1949 are described on the next page. We notice some different types of growing habits for many polyploid flower plants induced recently at our Farm. Most of them show distinctly vigorous growing, “Polyploid vigor” with larger flowers, thicker leaves and higher stems than normal diploids, as wallflower, stock, verbena and Lychnis charcedonica. On the contrary, however, some polyploids, for instance, double portulaca or Lychnis coronata, become much dwarf and shortened, and sometimes can not bear any seed at all as Four o'clock or double Impatiens. Although causes of this N polyploid feebleness is not cleared up why, a part of them possibly due to the genic over-action caused by a plenty of genes located on duplicated chro-mosomes.
