482 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
not nearly so decided. Female flowers occur in almost all the species 
except Moenchia erecta and Moehringia trinervia. In the Umbelliferse, 
with only a few exceptions, male flowers occur in addition to the 
hermaphrodite, less often female flowers. The various forms are 
described in detail for Euphrasia Odontites and E. officinalis , and the long 
and short-styled forms of species of Primula. Lists are appended of 
those species in which unisexual flowers or individuals occur at different 
periods in the time of flowering ; of species normally hermaphrodite, 
which occasionally produce unisexual flowers ; of the insects which are 
in the habit of biting through the corolla to obtain the honey ; and of 
the species of flower the corolla of which is pierced in this way. 
Fertilization of Ficus Roxburghii.* — Dr. D. D. Cunningham 
describes the remarkable phenomena connected with the development of 
the fruit of this species of fig in Calcutta. The receptacles or 
inflorescences are male and female, and the species is dioecious. Tlio 
male receptacles contain true male flowers which produce pollen, and 
modified or atrophied female or “ gall-flowers,” which never produce 
seed, but within the ovaries of which the eggs of an insect are deposited 
and undergo evolution. The female receptacles contain true female 
flowers, in which the eggs of insects are never found, and which produce 
fertile seeds. The ostiole or opening of both male and female receptacles 
is so obstructed by a covering of bracts, that the receptacles are almost 
closed chambers. But the perfect development of both male and female 
flowers is dependent on the access of the “ fig-insect ” to the interior 
of the cavity of the receptacle, without which neither of them attain 
functional condition. The insect most commonly found is a species of 
Eupristis. 
Although the development of embryos in the female receptacle is 
essentially connected with the access of the insects to the receptacular 
cavity, yet Dr. Cunningham believes that it is independent of the intro- 
duction of pollen by their agency. The nearly entire closure of the 
ostiole by bracts presents an almost insuperable obstacle to the intro- 
duction into the female receptacles of a sufficient quantity of pollen for 
the impregnation of every one of the ovules in the exceedingly numerous 
female flowers by a separate pollen-grain ; and but very few pollen- 
grains could be found within the female receptacles. Although it is 
possible that in some instances ordinary pollination may occur, yet the 
author asserts that the embryo is ordinarily formed independently of any 
such process, and arises as an outgrowth of the nucellar parenchyme 
outside the embryo-sac. Up to the period of insect-access, and of the 
initial development of the embryo, the embryo-sac retains its character 
of a simple uninucleate cell without oosphere, synergidae, or antipodal 
cells. The full development of both male and female flowers appears to 
be dependent simply on hypertrophy of all the tissues of the receptacle 
resulting from stimulation caused by the access of the fig-insects. This 
stimulation is the result of the female insects laying their eggs within 
the ovary of the “ gall-flowers ” in the male receptacles, and of their 
persistent attempts to do the same within the flowers of the female 
* ‘ On the Phenomena of Fertilization of Ficus Roxburghii Wall.,’ Calcutta, 1889, 
fob, 37 pp. and 5 pis. 
