1898 ] THE LIFE-HISTORY OF RANUNCULUS rT 
application, the exterior cell has been called the ‘primary wall 
cell,” as its derivatives enter into the formation of the wall; 
rather than the “ primary tapetal cell,” as its derivatives may or 
may not contribute to the tapetum. The interior cell resulting 
from the first division of an archesporial cell is well called a 
“primary sporogenous cell,” as the sporogenous tissue is derived 
from it, and often nothing else is. 
This very customary use of the term archesporium in con- 
nection with the microsporangia of spermatophytes, when log- 
ically applied to the macrosporangia of spermatophytes and the 
sporangia of other groups, leads sometimes to a terminlogy 
not at all customary. In the case of the macrosporangia of 
spermatophytes the term archesporium is applied in the same 
broad sense to the first distinctly differentiated cell. In this 
cell a periclinal division may or may not take place. If it does 
°ccur, as is usual, the exterior sterile cell has been called a 
tapetal cell, whether it functions as a tapetum or not, and 
whether it divides further or not. It seems evident that we 
have here the homologue of the primary wall cell of the micro- 
‘sporangia, which may form several layers, to call all of which a 
tapetum seems very questionable. In this case it is a question 
whether the problematical so-called “potential macrospores” do 
not function as tapetal cells, in which case the ‘fertile macro- 
Spore” may be regarded as the only real sporogenous cell. In 
view of the uncertain nature of these structures, however, no 
such terminology is adopted, and the current view that they are 
‘pore mother cells is retained. 
rie Sporangia as those of the eusporangiate Filicinee, 
‘es aoe a nee! application of the term archesponum changes 
eel bec oe. The distinctly differentiated superficial 
elias ai, és in this case the archesporium, and the usual peri- 
pigs: sion Separates the exterior primary wall cell from the 
Primary sporogenous cell (not archesporium). 
of Poe of aneh extremely modified sporangia as those 
ees 7 ‘sporangiates, the archesporial cell functions as sii 
in the development of the stalk, but the usual peri- 
