1899] DEVELOPMENT OF THE MICROSPORANGIUM 353 
aumber of chromosomes present, the spindles in the pollen grain 
ae exceedingly minute and slender (fig. gz). Fhe process of 
division here does not seem to present any new features. When 
preparing for division, the primary nucleus moves toward one 
side of the cell, so that the resulting spindle has one pole in con- 
tact with the cell wall. This pole unlike the free one, is not 
pointed; on the contrary, it is usually quite broad, so that the 
spindle fibers are attached to the wall over a considerable area. 
The spindle is quite dense and stains readily, but is composed 
olfew fibers. After the chromosomes pass to the poles a dis- 
tinct cell-plate forms, and is later followed by a definite 
| Membrane (fig. 42). The latter is arched in such a way as to 
cut off one daughter nucleus in a small lenticular cell, of which 
oe wall is the wall of the spore itself. This is the so-called 
seerative cell, 
The cytoplasm henceforth occupies the greater part of 
Be cell cavity. It gradually becomes filled with large bodies 
/Mhich stain purple with gentian-violet, and blue with iodine. 
‘y are in reality starch grains. A similar occurrence of 
| in in the pollen grain has been described in Naias by Camp- 
fe 
Slsely attached to the wall. The elongation produces an 
‘Mong cell, and is the first step in preparation for the second 
Ot. The chromosomes for this division are formed early. 
They ‘an often be seen to occupy nearly the entire nuclear 
“vity, and So distinct are they in many cases that one may 
om them. The number here again is uniformly seven. The 
; a were found in considerable numbers, one of ge : 
“tly aa 43. The spindle fibers are very coarse an — 
7 arcely more numerous than the chromosomes. Gu 
tan 'o stain more easily than is ordinarily the case in this 
a. The chromosomes are during this division seeniey 
% s 
Prog, Calif, Acad. Sci. III. +: 16, 1897. 
