Puccinia cognata
| Puccinia cognata | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Puccinia cognata | ||||||||||||
| P. Sydow & Sydow |
Puccinia cognata is a stand fungal art from the order of the rust fungi (Pucciniales). The fungus is a endoparasite the daisy family genus Helianthus , Iva and Heliopsis . Symptoms of the infestation by the species are rust spots and pustules on the leaf surfaces of the host plants. It is common in southern North America .
features
Macroscopic features
Puccinia cognata can only be recognized with the naked eye by means of the spore beds protruding on the surface of the host. They grow in nests that appear as yellowish to brown spots and pustules on the leaf surfaces.
Microscopic features
The mycelium of Puccinia cognata grows as with all Puccinia TYPES intercellular and forms Saugfäden that grow into the storage tissue of the host. Their spermogonia grow on the upper side of the host leaves. The aecia of the species growing underneath the leaves are cracked and stand in groups. They have 22–27 × 16–23 µm in size, spherical to ellipsoidal, colorless aeciospores with a warty surface. The uredia of the fungus, mostly growing underneath the leaves, are cinnamon brown. Their uredospores, which are also cinnamon-brown, are 24–28 × 19–25 µm in size, ovate to broadly ellipsoidal and spiky. The predominantly underside of the leaves of the species are black-brown, powdery, compact and uncovered. The light chestnut brown teliospores are two-celled, usually long ovate to long ellipsoid and 38–55 × 23–30 µm in size. Their stalk is yellowish and up to 150 µm long.
distribution
The well-known distribution area of Puccinia cognata extends from the southern USA to Guatemala .
ecology
The host plants of Puccinia cognata are various Helianthus , Iva and Heliopsis 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 development cycle with Spermogonia, Aecien, Telien and Uredien, but does not change host.
literature
- George Baker Cummins : Rust Fungi on Legumes and Composites in North America . University of Arizona Press, Tucson 1978, ISBN 0-8165-0653-1 .