344 BOTANICAL GAZETTE [NOVEMBER 
and the primary root is protruded into the soil from the end of the 
descending axis, the further descent of the stem apex begins. The 
sheath in the base of the cotyledon, in which the apical dome is 
located, elongates by the proliferation of the cells in the walls of 
the sheath so that the base of the cavity is lowered in reference to 
other points. As the structure so formed is positively geotropic 
in its growth response, it may conveniently be called a ‘‘dropper.” 
The apical dome, being inserted at the base of the sheath, is carried 
forward in the elongation as a terminal bud (figs. 10, 13). 
The dropper originates from the cotyledonary sheath through 
the irregular distribution of the dividing cells in the walls of the 
sheath. The base of the sheath is displaced laterally by the multi- 
plication of cells between the apical dome and the axis of the 
cotyledon (figs. 6-8). This pushes the base outward from its 
original position. While the displacement is proceeding in the 
lateral direction, an elongation is also taking place, so that the 
dropper begins to push forward into the soil during its displacement. 
Soon after the axis of the dropper becomes established as a direction 
of growth, the zone of elongation becomes confined to the region 
immediately adjacent to the base of the apical dome. This places 
the growing tissue close to thé apex of the dropper, as if it were a 
rhizome. 
The inclosing walls of the dropper do not grow equally, the 
axial wall elongating more slowly at first than the abaxial, result- 
ing in a lagging behind of the apical dome, in reference to the base 
of the sheath cavity. The stem apex thus becomes located on the 
side wall, instead of at the base of the sheath (fig. 13). The axis 
of the dome itself may become almost horizontal through this 
displacement. The oblique position of parts inaugurated at this 
stage of development persists through the life cycle, including the 
deep-seated bulbs of the flowering individuals. The lateral loca- 
tion of the stem apex at the base of the sheath cavity causes 4 
distortion of the outgrowths from the apical dome as they appear: 
The apical outgrowths push upward into the cavity about the stem 
apex, and thereby appear to be at nearly right angles to the axis 
of the dome (fig. 13). The rate of growth of the apical dome and 
that of the developing scale is so nearly identical that the dome 
