THE WILD AND WONDERFUL. “Sex in microbes often occurs in the absence of reproduction. Most plants simultaneously are female and male, and some plants and fish change sex over time. And in mushrooms, after gamete fusion sex is postponed until just before reproduction. These deviations from the ‘norm’ may hamper our general understanding of sexual reproduction if we phrase general theories based on rules that only apply within a subset of species.”
http://rstb.royalsocietypublishing.org/content/weird-sex-underappreciated-diversity-sexual-reproduction