The structure and development of the gynœcium, ovule and embryosac of
Cocculus villosus DC. has been studied.
There are generally three fertile carpels in a flower, but a fourth one is frequently present. The extra carpel is generally
abortive. The carpels are arranged in a spiral manner on the floral axis. In the beginning two ovules develop in each carpel.
Later the lower one of these is suppressed. These observations show that the few-carpellary gynoecium ofCoccufnts villosus has been derived by reduction from a multicarpellary structure and the uni-ovular carpel from a bi-ovular type.
The functional ovule is amphitropous up to the development of the embryo-sac, but becomes campylotropous during the formation
of the endosperm. There are two integuments, which remain free from each other and the nueellus up to the mature embryo-sac
stage. The micropyle is formed only by the inner integument. The nueellus is characterised by the development of a small epidermal
cap.
The primary archesporium is restricted to a single cell. A primary wall cellos cut off. The megaspore mother cell gives rise
to a linear tetrad of megaspores. The chalazal megaspore alone is functional. The development of the embryo-sac corresponds
to the normal type. The polar nuclei fuse at an early stage. The synergids possess small hooks and show a clear filiform apparatus
in the later stages. The antipodal cells develop large vacuoles.