Homothallic refers to the possession, within a single organism, of the resources to reproduce sexually;[1] i.e., having male and female reproductive structures on the same thallus.
Homothallism in fungi can be defined as the capability of an individual spore to produce a sexually reproducing colony when propagated in isolation.
[3] Homothallism occurs in fungi by a wide variety of genetically distinct mechanisms that all result in sexually reproducing cultures from a single cell.
[8] Cryptococcus depauperatus, a homothallic basidiomycete fungus, grows as long, branching filaments (hyphae).
Lichens occur in some of the most extreme environments on Earth—arctic tundra, hot deserts, rocky coasts, and toxic slag heaps.
Rather the lichen-forming fungi of these species reproduce sexually by self-fertilization (i.e. they are homothallic), and it was proposed that this breeding system allows successful reproduction in harsh environments (Murtagh et al., 2000).