Abstract
Obeservations of megaspore mother cell meiosis, fertilization and embryo development show Tridax procumbens to have a straightforward amphimictic type of reproduction. The embryo sac is monosporic and eight nucleate with prominent synergidae and the antipodal nuclei are contained within a short tubular haustorial outgrowth of one or three cells.
Fertilization follows within twelve to eighteen hours of pollination and embryo development conforms to the asterad pattern. No meiotic irregularities have been seen during division of the megaspore mother cell but this does not eliminate the possibility that a proportion of the observed 15% of sterile cypselas may result from meiotic failure rather than from failure of pollination or fertilization.
