Periodicity of the Nuclear Divisions in Crepis capillaris WALLR

Root tips of 5 pot-plants of Crepis capillaris were fixed at intervals of one hour during a day. Number of the dividing nuclei (excluding those of the late telophase, interphase and early prophase) at each time was counted. The stages in which the dividing nuclei were counted were classified into 6, namely, 1) late diakinesis and early mataphase, 2) metaphase, 3) late metaphase and early anaphase, 4) anaphase, 5) late anaphase and 6) early telophase. The results obtained are shown in Table 1. Two marked dividing periods and consequently two resting periods were observed as seen in Fig. 1. It is interesting to note that at the beginning of the dividing periods nuclei of the earlier stages are great in number, and at the end of the same periods many nuclei of later stages are observed (Figs. 2 and 3).