302 BOTANICAL GAZETTE [OCTOBER 
mother cells may doubtless be related to the probable hybrid nature 
of the form of Impatiens Sultani used. The distinction between 
the functional and non-functional sporogenous tissue can clearly be 
seen at an early stage, and still shows distinctly when the spore 
mother cells are in synapsis. The latter are still angular and are 
only just beginning to separate (fig. 20). 
As is customary at the time of synapsis, the chromatic substance 
is massed against the nuclear membrane, with the single large 
vacuolate nucleolus projecting out from one side. As the prophase 
of the heterotypic division advances and a delicate spirem fills up 
the nuclear cavity, the cells become almost entirely free and round 
off, while the tapetal cells still remain somewhat angular in outline 
and often contain more than the 2 nuclei of the earlier stage (fig. 21). 
Their nuclei have become granular, lack a nucleolus, and stain more 
densely than before. In general, the entire mass of cells has 
separated from the wall. The ovule at this age shows no sign of 
the inner integument. 
As the anther increases in size, the microspore mother cells 
become entirely rounded off and the spirem takes on a double 
appearance, whether due to a splitting of a single spirem or an 
approximation of two was not apparent. At this time the spirem 
is thicker and less delicate than the spirem immediately following 
synapsis (figs. 21, 22). The cytoplasm has an obscurely radiate 
appearance, being densely granular about the nuclear membrane 
and more vacuolate toward the cell membrane. The spirem 
thickens, becomes irregular, and segments transversely into bivalent 
chromosomes. The majority of the segments come to lie against 
the nuclear membrane and show clearly their double nature in 
the forms of X’s, Y’s, and V’s. They are rough in outline and are 
connected here and there by delicate threads (fig. 23), similar to 
those figured by Mortier (33) for Acer Negundo and Staphylea 
trifolia. The nucleolus still persists and at this stage there may 
be two, a large and a small one. 
The granular area surrounding the nucleus has become still 
more marked and closely resembles the kinoplasmic region described 
by ALLEN (1) for the pollen mother cells of Larix and by numerous 
other writers. The peripheral cytoplasm with its large meshes 
