Publisher Summary Three genera of liliaceous plants have been found to be particularly useful for biochemical studies of gametogenesis: Trilhm, Tulipa, and Lilium. Despite the extreme differences in conditions of development, the biochemical characteristics of the gametic cells are similar. The reason why similarities have been observed is that studies have been restricted to certain common events at the cellular level. This chapter discusses these events. The phenomena discussed are based on patterns observed in Lilium longiflorum. It is concerned mainly with studies done in laboratory. Studies in the laboratory have been addressed mainly to the intracellular events underlying gametogenesis. Such studies have a legitimacy of their own beyond the scope of developmental biology. Meiosis, in particular, is central to genetic theory, and an account of this process could stand by itself. The chapter provides reviews of the progress being made in the developmental field. It also discusses the evidence that bears on the relationship between the gametic cells and the organic environment in which they develop.