Microbotryum violaceum
Microbotryum violaceum, also known as the anther smut fungus, was formerly known as "Ustilago violacea". It is a Basidiomycete obligate parasite of many Caryophyllaceae. But it has now separated into many species due to its host specificity. Meiosis in "M. violaceum" produces a tetrad of four haploid meiotic products. Pairwise intra-tetrad mating can occur between these meiotic products. Examples. "M. violaceum" can infect and sterilize the plant species "Silene latifolia" by acting like a sexually transmitted infection.