|Dietel & Holway|
Puccinia zexmeniae is a stand fungal art from the order of the rust fungi (Pucciniales). The fungus is an endoparasite of the sunflower genus Zexmenia . Symptoms of the infestation by the species are rust spots and pustules on the leaf surfaces of the host plants. It is common in much of America.
Puccinia zexmeniae can only be recognized with the naked eye by means of the spore beds emerging on the surface of the host. They grow in nests that appear as yellowish to brown spots and pustules on the leaf surfaces.
The mycelium of Puccinia zexmeniae grows as with all Puccinia TYPES intercellular and forms Saugfäden that grow into the storage tissue of the host. Your spermogonia grow on both sides of the surface of the host leaves. The bilateral growing aecia of the species are cylindrical and whitish, they stand in small groups along the leaf veins . Their hyaline aeciospores are 20–30 × 15–19 µm in size, spherical to long ellipsoid and warty. The uredia of the fungus growing on both sides or mainly on the top of the leaf are cinnamon brown. The light cinnamon - brown uredospores of the species are 20–28 × 16–23 µm in size, almost spherical to ellipsoidal and spiky. The bilateral growing parts of the species are black-brown, powdery and uncovered. The dark chestnut-brown teliospores are two-celled, usually ellipsoidal to broadly ellipsoidal, wrinkled and usually 22–44 × 23–28 µm in size. Their stem is usually colorless and up to 150 µm long.
The host plants of Puccinia zexmeniae are diverse Zexmenia species. The fungus feeds on the nutrients present in the storage tissue of the plants, its spore beds later break through the leaf surface and release spores. The species goes through a macrocyclical development cycle with Spermogonia, Aecien, Telien and Uredien. As a self-sufficient parasite, it does not change host .