Der 
AND SPECIES-HYBRIDS WITHIN THE GENUS SACCHARUM 299 
opinion as to the way in which the higher chromosomenumbers arise 
from the lower ones. 
The chromosomenumbers 40 for S. officinarum, about 46 for Chun- 
nee and Ruckree II and 56 for S. spontaneum are particularly high ones. 
In the litterature, but one case among Angiosperms, with a higher 
chromosomenumber than 56, is, as far as I am aware, known e. g. the 
number 72 for Solanum nigrum gigas, a plant obtained experimentally 
by WINKLER !). 
Saccharum-species with a smaller chromosomenumber than 40 are 
not yet known 2). It is however quite possible that such exist or, at 
least have existed, and it seems to me that we have to count with the 
possibility that our Saccharum-species with a high chromosomenumber 
may have arisen from others with a ‘lower chromosomenumber. We 
shall refer to this later on. 
It was found, during the investigation of the reduction-division of 
Saccharum officinarum that the reduction is often incomplete. In the 
prophase of the division of the PMC an indefinite number of chromoso- 
mes may fail to pair. As a consequence the nuclear plate contains un- 
paired chromosomes besides the gemini. The latter apparently split, 
usually, longitudinally, but the possibility of unsplit single chromoso- 
mes reaching one of the poles, is by no means excluded. As a conse- 
quence the daughternuclei and the nuclei of the pollengrains also, will 
often obtain a number of chromosomes exceeding the haploid number 
40 of S. officinarum. 
ROSENBERG 3) could show such a thing in the case of species of the 
genus Hieracium; of Hieracium aurantiacum he writes: 
„Da, wie oben gezeigt, etwa 36 Chromosomen in den somatischen 
Teilungen auftreten, und in der Meiosis ungepaarte Chromosomen in 
nicht geringerer Zahl vorhanden sind, so ist es klar, dass nicht immer 
18 Gemini gebildet werden, d. h. die Affinität zwischen gewissen Chro- 
mosomen fällt weg. Oder vielleicht ist es richtiger, dass zuerst eine 
1) Hans WINKLER. Ueber die experimentelle Erzeugung von Pflanzen mit 
abweichender Chromosomenzahl. Zschr. f. Botanik. Jahrgang 8. 1916, p. 441. 
2) Teboe hitam Rokan, which has approximately 30 chromosomes in the ha- 
ploid phase is probably a species-hybrid. 
3) C. ROSENBERG. Die Reduktionsteilung und ihre Degeneration in MTieracium 
p- 163. j 
