The intersexual plant of R. Acetosa generally bears flowers of three types, namely male, female and bisexual ones. The male and female flowers are morphologically normal, but the bisexual ones sometimes show various grades of degeneration (Fig. 1-6). Numbers of these different flowers in each plant are variable and usually female flowers are few or absent. Accordingly we have determined the degrees of intersexuality in each plant by calculating the percentage of bisexual flowers.
The chromosome numbers of 50 different individuals in various grades of intersexuality are denoted in the following table:
It is pecuriar that some diploid individuals show a low intersexuality. The chromosomal elements of such individuals, however, appear similar to that of the male plant (Fig. 7-10).
Some intersexual plants of R. Acetosa are fertile. I have obtained many progenies. Among the progenies of triploid intersexual plants, 15-, 16- and 20-chromosomal individuals were found (Fig. 11). Further investigations of these progenies will be reported later.
VII. Chromosomes of R. montanus.
The numbers of diploid chromosomes in female, male and intersexual plants of R. montanus were determined respectively to be 14, 15 and 22. The behavior of chromosomal elements is quite identical with that in the case of R. Acetosa (Fig. 12-14). Therefore the chromosomal formulae of these plants should perhaps be as follows:-_??_14=12a+2X _??_15=12a+X+2Y _??_22=18a+2X+2Y
VIII. Chromosomes of an intersexual plant of R. acetosella.
This summer (1929) I collected some fertile intersexual plants of R. acetosella from two different places in South Saghalien. One of them was fixed and studied cytologically. In the heterotypic nuclear division in pollen mother cells we found 20 bivalents and one univalent (Fig. 15). Some bivalents associate with each other and form one or more tetrapartite ring-complexes (Fig. 16). In the anaphase, the univalent goes freely to one pole. Therefore the daughter plates have usually 21 and 20 chromosomes (Fig. 17, 18). We are not yet sure whether all the intersexual plants of R. acetosella have 41 chromosomes or not.