1921 年 35 巻 418 号 p. 184-190
1. Some account about the mode of culture of gametophytes and the method of testing their maturity were given.
2. Isoetes japonica has five or six archegonia in a female gametophyte, but sometimes more than ten. When fertilization takes place in one of them, the others degenerate; in rare cases the fertilization takes place in two or more of them and the embryos develope up to certain stages.
3. Near the nucleus of the egg cell, there appear sometimes one or more rounded bodies, which stains with iron-alumhaematoxylin just as the nucleus, but the closer examination of their structure showed that they are to be interpreted as chromatophores.
4. Certain abnormalies in the formation of the ventral canal cell and the egg cell have been described.
5. In exceptional cases, macrospores and microspores are produced in one and the same sporangium.
6. Diploid chromosome number of Isoetes asiatica is twentytwo, and that of Isoetes japonica is fourtythree to fourtyfive, i. e., nearly twice as that of the former.
7. Hybrids of I. japonica×I. asiatica as well as of I. asiatica× I. japonica were raised, the further account of which is reserved for the future.