AND SPECIES HYBRIDS WITHIN THE GENUS SACCHARUM 103 
cies of Saccharum have been investigated, it was thought advisable to 
try to determine the chromosome numbers in the pollen-mother cells. 
Not only that they — as well as the enibryosacmothercells — have 
much larger nuclei than the vegetative tissue, but in these cells, as is 
well known, the number of chromosomes is reduced to one half during 
karyokinesis. In the prophase of the division the chromosomes arrange 
themselves in pairs, which by a process of shortening finally take the 
aspect of almost isodiametric clumps, which can easily be counted, the 
more so as their number is only one half that of the chromosomes in ve- 
getative tissue. The chromosomes in dividing nuclei in rootpoints on 
the other hand, are curved longitudinally, stretched, and double in num- 
ber, which makes counting so difficult that it is well nigh impossible to 
State their exact number. 
We therefore must determine in the first place, at which stage in the 
development of the inflorescence dividing pollenmothercells are present. 
The Saccharum-inflorescence is a compound panicle; the main axis 
carries lateral axes of the first order,these such of the second order,even 
axes of the third order may occur. The lateral axes of the second order, 
eventually those of the third order also, are racemes with stunted inter- 
nodes. At the nodes of these racemes we find, alternately placed on the 

Fig. la. 
axis, a pair of spikelets, consisting of a sessile and a peduncled spikelet. 
Each spikelet is surrounded by a row of long hairs, inserted at the base 
of the spikelet. The spikelets are uni-florous. Fig. 1 shows the diagram 
