Studies on the Cytology of some Species of Taraxacum. 
463 
albidum, showin g considerable irregularities in their development, for 
the original form, from which such a regulär member as T. platycarpum 
was derived. The similar relation we can see in Banana, studied by 
Tischler (1910). He found that three races of Banana, called “ Dole ”, 
“ Radjah Siam ”, “ Kladi ” appear to have 8, 16 and 24 chromosomes as 
their respective haploid number. In l ' Dole ” (8) the nuclear division of 
the pollen-mother-cell is cpiite normal, while “ Kladi" (24) is very ab- 
normal in this respect and produces only sterile pollen-grains. Marchal’s 
(1909) bivalent varieties of the mosses appear to show a similar relation. 
b) Cell-size and Chromosome-Number. 
The very first examination of T. albidum revealed me the fac-t that 
the pollen-mother-cell as well as its nucleus are considerably larger than 
those of T. platycarpum. I tried to ascertain whether this difference 
is constant or not and whether here also the Boveri’s (1905) law, con- 
cerning the relation between the number of chromosomes and the size of 
nucleus may hold or not. Similar studies were already made in Oeno- 
thera by Gates (1909); in mosses by El. and Em. Marchal (1909) and 
in Banana by Tischler (1910). In Oenothera Lamarckiana , the number 
of chromosomes is 7 for the gametophyte, while in O. (jigas there are 
14 of them, and the ratio of the volumes of the nuclei of pollen- 
mother-cell in synapsis stage was nearly 1 : 2. In the bi- and tetra- 
valent races of mosses, produced artificially, El. and Em. Marchal 
found also the similar relation. For example, in Amblijstegium serpens 
2 n and 4 n 1 ), the ratio of the volumes of the nuclei of the rnother-cells 
is 1 : 2.1 before synapsis, 1 : 17 in synapsis. In Mnium hornum ln and 
2 n 2 ), the volumes of nuclei of the antheridium in various stages have 
the ratio of 1 : 1.7; 1 : 2.1; 1 : 2. 
In three races of Banana, u Dole'\ u Radjah Siam ”, li Kladi ”, Tisch- 
ler found that they have respectively 8, 16, and 24 chromosomes and 
that the volumes of their respective nuclei stand to eacli other in the 
ratio of 1 : 2 : 3. 
In my present investigation I have measured 25 nuclei of the 
pollen-mother-cell in spirem stage in botli species, for then the nu- 
cleus reaches its greatest size. The number in the following table 
shows that of the parts of an ocular micrometer, each part measuring 
0.00167 mm. 
!) 2 n and 4 n mean bivalent and tetravalent respectively. 
2 ) 1 n and 2n mean univalent and bivalent respectively. 
