How has the male gametophyte evolved in these four phyla Bryophyta, Pteridophyta, Coniferophyta, and Magnoliophyta? In which phyla do the male and female gamete-producing structures occur on the same gametophyte? Which phyla require water for the sperm to reach the egg? In which phyla do the gametophytes depend upon the sporophytes? And finally, how do the changes in the male gametophyte relate to the great leaps forward” in plant evolution?