Silene latifolia is a plant with separate male and female flowers. When infected by a certain fungus, the female flower starts to develop male reproductive parts. Researchers studied a mutant plant without male or female parts and infected it with the fungus. They found that the male part developed, but the female part did not. This suggests that the fungus only affects the development of male parts in the plant. The fungus seems to have a role in promoting the growth of the male reproductive structure in the plant.