98 
WRIGHT : THE GENUS DIOSPYROS 
been derived from a hermaphrodite type by sterilization 
without reduction in number of parts. 
If the unisexual type was the primitive, the flowers are 
now perhaps progressing towards the production of an 
uniform hermaphrodite type. When one considers how 
definitely monoecious or dioecious many other species are, 
and that sterilization of sporogenous tissue is frequently met 
with in the ontogeny and phylogeny of the higher plants, it 
seems more reasonable to regard the more specialized 
condition of unisexuality as the latest phase in development, 
and, in view of other facts, to believe that the hermaphrodite 
condition is the more primitive in this genus. The female 
inflorescences in many species appear to have undergone 
much abortion ; this is probably true of the parts of the 
flower also. It is not meant to imply that the species 
showing this condition are necessarily members of the most 
primitive section of Diospyros. The statement is made 
purely in relation to the evolution of sex in Diospyros, a 
development which may or may not be correlated with that 
of the vegetative organs. 
It would therefore seem an easy task to derive the present 
mixed sexual condition in D. hirsuta from a primitive 
hermaphrodite flower. In the production of female from 
hermaphrodite flowers the anthers, though persisting, 
become barren. It seems more reasonable to regard a 
staminode as being a stage in the abortion of a stamen, rather 
than one in the development of a stamen towards fertility. 
If, however, we consider another species showing the same 
variation in sex, viz., D. Thwaitesii, the evolution from the 
hermaphrodite flower is more complicated. In this species 
the staminodes are, as in the female flowers of D. hirsuta, 
five in number and arranged on the corolla so as to alternate 
with their lobes. In the male flowers, however, the number 
of stamens always exceeds that of the staminodes of the 
female flower, there being usually ten, and in one case 
twelve fertile stamens present. It is interesting to note 
that when there are ten stamens present these are arranged 
