Abstract
1) There are considerable variations in fertility and karyotypes of Crepidiastrixeris denticulato-platpphiilla Kitamura collected at Aburatubo near Misaki (Fig. 3-18).
2) The number of florets and involucre scales per head was counted. The fertility was determined directly by the ratio of the number of ripe achenes to that of florets. The plants with 11 florets have the highest fertility (Table 2). These plants seem to be different in some way from the F1 hybrids which have 9 florets.
3) The number of involucre scales is much more stable than the number of florets (Table 3). This character shows incomplete dominance and seems to be conditioned by the polymeric genes like many other quantity characters.
4) One hypoploid (monosomic) form (Fig. 3), one with diploid-tetraploid chimera (Figs. 14 and 15) and one tetraploid form (Figs. 18, 20 and 21). But these tetraploid plants seem, to be of secondary occurrence after transplantation into the experimental garden from the mild climate of the coastal region.
5) Meiotic divisions of some plants were studied. Pairing and separation of chromosomes proceed fairly regularly. In the tetraploid plants also a regular formation of tetravalents was observed (Figs. 23-25).
The writer wishes to thank Prof. Y. Sinoto of the Tokyo Imperial University under whose direction and guidance these investigations have been undertaken, and also Prof. VI. Eri of the Marine Biological Station of the Tokyo Imperial University, who facilitated him to collect the plants used in the present work.
