The evolution of the androecium in theOrchidaceae shows three major trends. There is a progressive trend in the degree of fusion of the filament(s) and staminode(s) to the gynoecium. Secondly, there is a reduction in the number of fertile anthers. Finally, there is a progressive change in the position of the base of the anther relative to the apex of the stigma; in the more primitive orchids the apex of the stigma is always higher than the base of the anther (this position is reversed in the higher orchids). All three trends reflect variation in the evolution of pollen dispersal and pollen reception mechanisms in theOrchidaceae. Trends in the evolution of the orchid anther(s) tend to parallel trends in the evolution of their pollinaria.