106 A CYTOLOGICAL INVESTIGATION OF SOME SPIECES 
a fertile one, about three monthes before flowering. The last leaves for- 
med by the growing point before transformation have a deviating sha- 
pe. This allows us, to recognise which of the sugar-cane stems in a field 
are destined to flower. WILBRINK and LEDEBOER 1) have given a good 
description of these appearances. They say: 
„Ihe first indications of flowering of sugarcane, are furnished by 
the fact, that the distance between successive leaf joints, which normal- 
ly decreases towards the top, now begins to increase at the highest 
joints. This is caused by a lengthening of the successive leafsheaths. 
Joined to this is a steep direction of the topleaves, caused by the suc- 
cessive shortening of the leafblades. If we determine the longitudinal 
proportion of sheath and blade in the case of successive leaves below 
the inflorescence, we see that the more the sheath lengthens, the blade 
shortens and that, consequently, the whole length of the leaf remains 
approximately constant. The last leafsheath, the one which encloses the 
inflorescence, can reach a length of more than one meter, the last leaf- 
blade, the so called flag, is usually not longer than a few decimeters (in 
the case of the kind known as G. Z. 100 about 40 cM against the 95 cM 
of the sheath)”. They also remark: 
„Ihe midrib is very weakly constructed at the base of the leaf- 
blade, so that de blade easily gives away at that point and subse- 
quently hangs downwards; this happens especially frequently to 
the flag. The further pushing apart of the leafpoints, is caused 
besides ‘by the greater length of the leafsheaths, also by the leng- 
thening of the internodes towards the top.” 
Usually 7 or 8 floral leaves are found at a flower-stem. As long as the 
blades of these have not all appeared above the case formed by the 
sheaths of the vegetative leaves, but when the metamorphosis of the 
„leaf-crown” is already visible the Javanese call the cane-stem, which 
shows this appearance ,boenting’’ (pregnant). This boenting-condi- 
tion becomes more and more conspicuous the more the blades of the flo- 
ral leaves appear. About 3 weeks after the first indications of „pregnan- 
cy’’, the flag appears. The pushing far apart of the leaf-sheaths occurs 
during the , flag-period’’ because the stretching of the highest interno- 
des does not begin until all leafsheaths are full-grown. The axis be- 
tween the highest stem-internode and the axil of the lowest lateral axes 
1) G. WILBRINK en F. LEDEBOER, De geslachtelijke voortplanting bij het sui- 
kerriet. Arch. XIX. 1911, p. 368. 
