304 ; BOTANICAL GAZETTE [NOVEMBER 
species of Rumex, among them R. crispus. He found the haploid 
number of chromosomes in the microspore mother cells to be 8 in 
R. Acetosa, R. hispanica, R. arifolius, and R. nivalis; 16 in R. 
Acetosella; and probably 4o in R. cordifolius. R. Acetosa appar- 
ently undergoes reduction in the megaspore mother cell, although 
he saw no indication of subsequent fertilization. The embryo 
sac very frequently degenerates. He found evidence of apogamy in 
some species, and thinks it probable that, at least in the group 
Acetosa, this has been the result of dioecism. STRASBURGER (9) 
early investigated Polygonum divaricatum, and his figures of the 
origin and development of the embryo sac have become a classic 
example of normal behavior. 
Material and methods 
Inflorescences and individual flowers of various ages were 
collected along street borders near the University of Chicago, and in 
a flood plain pasture near Mineral Springs, Indiana, during the 
summers of 1915 and 1916. They were killed in chrom-acetic, 
imbedded in paraffin, and cut in the usual manner. Both iron 
alum-hematoxylin and safranin-gentian violet were employed for 
staining. 
Some of the most important features of the morphology became 
apparent in the course of the investigation during the winter of. 
1916-17, and as no more material could be obtained then, there 
remain some points the solution of which requires the collection of 
more flowers and careful observations on the growing plants. 
Normal development 
ORGANOGENY.—The young inflorescence of Rumex crispus is 
closely invested by the sheaths of successive bracts. It is pro- 
fusely branched, and the branches bear flower buds of considerable 
size before they emerge from the protecting sheaths. All the young 
parts are covered with a mucilaginous secretion, rendering the 
penetration of reagents slow. 
The flowers are borne in clusters at the nodes. The oldest are 
nearest the main stem, while the successively younger arise outside 
these, on the upper surface of the enlarged projecting nodes. 
