100 WRIGHT : THE GENUS DIOSPYROS 
hermaphrodite and dioecious condition. It is important 
to realize that here we have a species which is mainly dioe¬ 
cious, but where the staminal whorls of male and female 
flowers agree in number, if we regard a group in the male 
as equivalent to one member in the female. 
In the species belonging to this group the production of a 
pistillate flower is attained by sterilization of the male 
sporogenous tissue (the anther still persisting) followed by 
a reduction of pairs or groups to single members. The 
original hermaphrodite flower still occurs on polygamous 
trees and always possesses stamens of different sizes, the 
innermost being the smallest. 
The accessory whorls of the male and female flowers of this 
and in fact of all the other species are widely different, but since 
the differences are those of size and form they may be neglected 
in considering the evolution of unisexuality in Diospyros. 
If we now consider the species in Group B, D. acuta and D. 
oppositifolia, which are only known in the monoecious 
condition, we find that they can be easily arranged in a 
series to show the similarity in the whorls of male and 
female flowers. In D. oppositifolia the female flowers 
usually possess four epipetalous staminodes alternating with 
the corolla segments. In one female flower there were eight 
separate staminodes arranged so as to be alternate with and 
opposite to the corolla segments, each being typical in 
form and possessing a completely barren anther. In the 
male flowers of this species there are always eight epipetal¬ 
ous stamens usually paired, with the inner member the 
shorter of the two, but each stamen is attached to the corolla 
by its own filaments. The pairs invariably alternate with the 
corolla segments, though this orientation is liable to variation. 
The variation in the male staminal whorl is where the 
members of one or more pairs are not exactly opposite one 
another, a deviation from the normal which tends to simu¬ 
late the occasional eight separate staminodes of the female 
flower. It is therefore very easy to correlate the staminal 
whorl of the male and female flowers of D. oppositifolia with 
