Cytological study of two peculiar hybrids found in natural populations of Crepidiastrum Keiskeanum

Abstract

Two intergeneric hybrids found among the natural population of Crepidiastrum Keiskeanum in Izu were studied cytologically. Simoda 4 seems to be a hybrid between C. Keiskeanum and Paraixeris denticulata. The cells with 10, 8, 7, 5 chromosomes are observed in root tips of this individual in a chimeral state. Misaki 3 considered to be a hybrid between C. keiskeanum and Lactuca squarrosa, consists of the cells with 18, 17, 15, 14 chromosomes. Not only the number of chromosomes but their karyotypes are different from cell to cell even in one individual.