Some species, such as Antennaria parlinii, contain both sexual and asexual individuals. We have been studying the extent to which populations are differentiated in terms of sexuality, and the association between asexuality and other life history traits. So, populations containing only females are functionally asexual. Using population surveys in conjunction with field and greenhouse experiements, we have shown that there is strong differentiation among populations for sexuality. Our studies support this hypothesis by showing that asexuality is associated with other life history traits that facilitate the colonization of ephemeral habitats.
Asexual plants invest a lot more in reproduction, producing twice as many seeds as as sexual plants.
Reports in the literature suggest that colonization in the monotypic emergent aquatic Butomus umbellatus is associated with a shift to asexual reproduction. There are also triploid populations with very low sexual fertility. In contrast, introduced populations in North America are reported to be diploid but exclusively sterile. The degree of sexuality in introduced populations will greatly influence the rate and pattern of spread in the adventive range and will have a large impact on our ability to control invasive populations with biological control. So far, our results clearly show that, contrary to earlier reports, most populations of Butomus are highly fertile and self-compatible.