326 A CYTOLOGICAL INVESTIGATION OF SOME SPECIES &c. 
If an investigation of a much larger number of these hybrid indivi- 
duals, should show, that the haploid chromosomenumber is really 68 
and, moreover, that Saccharum-hybrids with other chromosome-num- 
bers behave in a corresponding way — which so far seems highly pro- 
bable — the splitting of the chromosomes in the zygote will be proved. 
This will, of course, sustain WINGE’s theory to a great extent. It can 
now already be said, that the haploid chromosomenumber approaches 
the theoretical number 68 so closely, that the triploid nature of these 
hybrids is highly probable. 
In crosses of S. officinarum with S. spontaneum the former species 
has always been used as the mother. Whether the reciprocal cross is 
possible, we do not know. Evidently such a cross will meet difficulties, 
because the pollen of S. sbontaneum is much more fertile than that of 
S. officinarum. Castration has consequently certainly to be applied. In 
case this cross should succeed, it will be interesting to determine the, 
chromosomenumber of these hybrid individuals. 
One would be able to conclude from this chromosomenumber whether, 
here also, the S. officinarum-chromosomes split longitudinally, or 
whether all chromosomes do so, ci one could imagine a third possi- 
bility e. g. that the S. spontaneum-e romosomes undergo fission. If an 
other number of chromosomes than in the reciprocal cross appeared, 
one could moreover determine whether this-was accompanied by ano- 
ther habit of the hybrid individuals. The interesting behaviour of hy- 
brids between S. officinarum and S. spontaneum makes an extended 
investigation of these hybrids highly desirable. It is of course possible, 
that some of these hybrid individuals will behave cytologically in 
another way. Of many forms of the genus Saccharum the chromosome- 
number is, so far, unknown and the possibility is of course not excluded 
that hybrids of these forms will prove to be diploid or tetraploid. 
Hybrids within the genus Saccharum will probably allow us to settle 
whether the opinion of ERNST and WINGE, that forms with a higher 
chromosomenumber can arise by crossing from forms with a lower 
number, is well-founded. 
