76 BOTANICAL GAZETTE [FEBRUARY 
The primary sporogenous cells do not divide extensively, 
each cell dividing once or twice, so that the mother cells are 
only two or three times as numerous as the primary sporogenots 
cells (fig. 6). Disorganization of the tapetum and wall layers 
begins early, so that the mother cells soon become quite free in 
the loculus (figs. 4, 6). ; 
In the development of microspores the usual sequence dl 
events was observed, an ordinary series being shown in figs. 7- 
zo. The four spores may be arranged in the usual tetrahedral 
fashion (fig. 77), or may lie in the same plane (fig. 72). I 
both divisions of the mother cell numerous free nucleoli welt 
form may involve the nucleus itself, or it may be due entirely 
the aggregation of the cytoplasm in polar position, the whole 
distinctly invested by a “ Hautschicht.” . 
The term archesporium must either be restricted s0 ae 
apply only to those cells which produce mother cells or thet 
equivalents, or it must be extended so as to include those differ 
entiated cells which produce wall cells, tapetum, and sporoger 
ous cells. It is in the latter sense that the term has been used 
: This has seemed the more desirable use of the term, 
1s fat more definite and easy of application. Such a cell 
distinctly differentiated, but its progeny may vary considerably 
and in the case of Ranunculus the restricted use of archespontu” 
might or might not involve the tapetum. . 
In the first division of an archesporial cell, in its large 
