82 BOTANICAL GAZETTE [avcust 
Flemming’s triple stain; a combination of anilin-safranin with 
iron-alum-hematoxylin; and anilin-safranin followed by picte- 
nigrosin. The last named gave the best results in staining the 
incipient spindles. 
DEVELOPMENT OF THE MICROSPORANGIA. 
A cross section of a very young stamen, at the point where 
the microsporangia are to be formed, shows merely a rectangular 
area which consists of epidermal and general tissue cells. Three 
or four hypodermal cells of each sporangium become differenti: 
ated as archesporial cells. These divide by periclinal division, 
giving rise to the primary sporogenous cells and the primal) 
tapetal layer. The cells of the primary sporogenous tissue mul 
tiply rapidly, forming only sporogenous cells. The division 0! 
these cells is practically complete when the primary tapetl 
layer begins to divide. While the sporogenous cells are enlarg: 
ing the division of the primary tapetal layer takes place, ye 
ing a wall layer and an inner layer. The inner layer divides 
once, forming an intermediate or middle layer, and the layet 
which develops into the peripheral part of the tapetum a 
axial part being derived from the adjacent general tissue. 
DIVISION OF THE MICROSPORE MOTHER CELL. 
A typical spore mother cell when division begins (fg) 
shows a large nucleus in the center, with radiations in the cyt? 
plasm extending from the nucleus outward toward the cell wal 
There is usually a layer of deeper staining cytoplasm next * 
nucleus, and one or more large nucleoli just within the nucle 
membrane. The young spindle is bipolar from its first apper 
ance, each pole being dome-shaped for a time ( figs. 10). 
spindle encloses the nucleus through which the chromosom™ 
are scattered, and the layer of deep staining cytoplasm _ 
moved outward from the nucleus spindle lies wholly within ™ 
The radiations above described appear to be of the same ea 
and to have the same function as those described in animal c” 
such as fish eggs, If they are consumed in spindle formation 
