Just as the uredospores and aecidiospores both show these specialized characters in the case of Puccinia graminis so we find that both the conidia and ascospores of E.
A similar specialization has been observed by Marshall Ward in the Puccinia parasitic on species of Bromus, and by Neger, Marchal and especially Salmon in the Erysiphaceae.
The rust fungus, Puccinia graminis, is a Uredine belonging to the heteroecious group, that is, one that passes from one host to another at different stages of its life-history.
Eriksson found, for example, that the well-known species Puccinia graminis could be split up into a number of forms which though morphologically similar were physiologically distinct.
Similarly with Anemone infested with Puccinia and Vacciniusn with Catyptospora, and many other cases of deformations due to hypertrophy or atrophy.