Fertilization in mosses is limited by the fact that sperm has to swim between the male and female shoot. One strategy to deal with this problem is to have the males as tiny epiphytes on the female (dwarf males) to decrease the fertilization distance.
There are many unanswered questions about these dwarf males. Why can you find them in some populations and not in others? How does this sexual system affect genetic variation within populations? How do the female shoots regulate germination and growth of males? How are the dwarf males related to their female "host"?
To answer these questions we are working with a variety of methods such as field studies, cultivation experiments and molecular methods.
Yet to come!