400 BOTANICAL GAZETTE [NOVEMBER 
so that in each loculus there come to be 9-12 mother cells in trans- 
verse section, and 15-20 in longitudinal section (fig. 57). Just 
before reduction there is conspicuous enlargement of the anther, 
stretching the walls of the mother cells, and allowing the protoplasts 
to round off. The cytoplasm of the mother cells is rather dense 
and finely granular, and the nuclei are large with scanty chromatin. 
Reduction appears to be normal. No attempt was made to 
trace the details. At diakinesis there are 32 pairs of chromosomes 
(fig. 60), as found in the megaspore mother cells. The formation of 
a tetrahedral tetrad, the development of a thick cellulose wall about 
it, wall formation about the microspores, and liberation of the 
microspores from the tetrad by disorganization of the thick common 
wall, all follow the usual procedure for dicotyledons. At first 
rather dense, the cytoplasm of the microspores does not keep pace 
with the enlargement of the cell, and becomes rather finely vacuo- 
late (fig. 64). It is not certain whether this is entirely normal; 
indeed, degeneration is so universal that it is difficult to determine 
whether there is such a thing as normal development of the micro- 
spore. 
The nucleus of the microspore divides into tube and generative 
nuclei, and the latter organizes a small cell about itself (figs. 67, 68). 
Before shedding, the generative cell produces two male nuclei 
(figs. 71, 72); very few pollen grains ever reach this stage with 
anything approaching what may be considered normal appearance. 
The exine becomes well thickened and delicately rugose. Three 
germ pores are formed, beneath which the intine is slightly thick- 
ened (figs. 65, 66); they are connected with each other by furrows 
over the surface. 
FERTILIZATION.—Any conclusion for or against fertilization must 
for the present depend entirely on negative evidence. Some of the 
facts observed point rather conclusively to the occurrence of fertili- 
zation. There is no doubt that there is diakinesis in the megaspore 
mother cell, that there are 32 diads, and that this is the number 
present in the microspore mother cells also. While the exact 
number of chromosomes on the spindle of the heterotypic mitosis 
could not be counted, it appears to be 32 (fig. 27); the achromatic 
figure has all the characteristics of a reduction spindle; and finally a 
