Anther smut belongs to the Class Basidiomycetes in the fungal Division Eumycota. Anther smut is spread by unsanitary, promiscuous insect pollinators who carry the infectious spores from one plant to another. The spores infect healthy individuals during the spring flowering season, erupting in their sex organs a year later when the plants once again enter their mating cycle. Floral castration is a rather drastic measure and infected individuals are seldom taken to a smut clinic, so diseased plants just keep on reinfecting the population. Safe sex is effective, but slipping miniature condoms over the anthers is tedious and much too impractical.
Wise plants avoid the risk of sexually transmitted diseases by developing an asexual life style.
They simply clone themselves vegetatively. Some can even produce apomictic seeds without sex. The embryo develops parthenogenetically from an unfertilized egg or from other cells in or surrounding the embryo sac. References Thrall, P.H., Biere, A. and J. Antonovics. 1993. The Occurrence of Ustilago violacea On Different Species Within the Caryophyllaceae.