Rust (fungus) only uredinia and telia. Spermagonia may be absent from each type but especially the microcyclic life cycle. In macrocyclic and demicyclic life cycles, the rust may be either host alternating (heteroecious), i.e., the aecial state is on one kind of plant but the telial state on a different and unrelated plant, or non-host alternating (autoecious), i.e., the aecial and telial states on the same kind of plant. Heteroecious rust fungi require two unrelated hosts to complete their life cycle, with the primary host being infected by aeciospores and the alternate host being infected with basidiospores. This can be contrasted with
Stem rust studied the stem rust. Thirty years later it received its name, "Puccinia graminis", by Persoon, and in 1854 brothers Louis René and Charles Tulasne discovered the characteristic five-spore stage that is known to some stem rust species. The brothers were also able to make a connection between the red (urediniospore) and black (teliospore) spores as different stages within the same organism, but the rest of the stages remained unknown. Anton de Bary later conducted experiments to observe the beliefs of the European farmers regarding the relationship between the rust and barberry plants, and after successful attempts to connect the basidiospores