4l4 BOTANICAL GAZETTE | JUNE 
certain points which seem to merit comment. It seems best, 
however, to preserve the sequence of events for the benefit of 
those who may not have access to the more extensive papers. 
The students whose observations have supplied the data for this 
portion of the contribution, and whose individual contributions 
may be recognized by the initials appended to the different fig- 
ures, are Otis W. Caldwell, John G. Coulter, Henry C. Cowles, 
T. C. Frye, Nina D. Holton, Florence M. Lyons, William D. 
Merrell, Mabel C. Merriman, and Wilson R. Smith. 
DEVELOPMENT OF THE EMBRYO SAC. 
A single large hypodermal archesporial cell very early makes 
its appearance, distinguished by its size, contents, and very 
prominent nucleus (fig. 7). No evidence of the cutting off of a 
tapetal cell, or a division into potential macrospores was detected. 
The sequence of cell divisions usual in angiosperms is entirely 
suppressed, and the archesporial cell develops directly into 
the macrospore (embryo sac). It will be remembered that there 
are three possibilities in what may arise from the archesporial 
cell of angiosperms. It may, and apparently usually does, give 
rise at its first division to a primary tapetal cell and a primary 
sporogenous cell, each of which may give rise to a more or less 
extensive cell progeny; or it may, less frequently, give rise to 
no tapetal region, but play the part of a primary sporogenous 
cell and divide into potential macrospores; or it may, apparently 
exceptionally, develop directly into the fertile macrospore. This 
extreme shortening of the history of the embryo sac, recorded 
as yet only for Lilium and certain allied liliaceous gener@ 
. obliterates the distinctions between archesporial cell, primary 
_ Sporogenous cell or mother cell, and macrospore, so far as distinct 
cell existence is concerned, but what the ellipsis involves in 
nuclear and cytoplasmic changes is worthy of research. Certain 
it is, that this remarkable cell has a relatively long existence in 
the uninucleate condition, brought to a close by its rapid enlarge . 
4 ‘ment. sie. Scat is no tapetum, and no periclinal divisions ocCUF 
in th ie ia ase the mass of the nucellus seczia the “ 
