The carposporophyte develops from the zygote nucleus following fertilization. It is thus diploid. It remains within the female conceptacle, which enlarges to accomodate it. In the diagram, the carposporophyte is seen to consist of the gonimoblast filaments (g), each of which terminates in a carposporangium (c) which produces a single carpospore. In this case, the gonimoblast filaments arise from the periphery of a single discoid fusion cell (arrow). The filaments making up the walls and roof of the conceptacle are haploid filaments of the gametophyte. The conceptacle and its contents are sometimes referred to as a cystocarpic conceptacle, although strictly speaking it is still a female conceptacle.
Titanoderma pustulatum (UWC: 93/176)