Exobasidium horvathianum
| Exobasidium horvathianum | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Exobasidium horvathianum | ||||||||||||
| ( Thomas ) Nannfeldt |
Exobasidium horvathianum is a mushroom art family of Nacktbasidienverwandten (Exobasidiaceae) from the order Ustilaginomycotina . It is an endoparasite of Rhododendron luteum . Symptoms of infection by the fungus are pale to orange-red galls on the leaves of the host plants. The range of the species includes Eastern Europe and Asia Minor .
features
Macroscopic features
Exobasidium horvathianum is initially invisible to the naked eye. Symptoms of the infestation are red, up to 7 cm wide and 3 cm high, pale to orange-red plant galls on the leaves, wrinkled leaf tips and, in the late stage, protruding mycelium on the underside of the leaf .
Microscopic features
The mycelium of Exobasidium horvathianum , like all naked basidia, grows intercellularly and forms suction threads that grow into the host's storage tissue. The four-pore, 6–7 µm wide basidia are unseptate. They grow directly from the host epidermis or from stomata . The banana-like shaped spores are hyaline and 13-14 × 3 µm in size. At first they are unicellular, when ripe they show up to three septa . Apparently there are no conidia .
distribution
The known distribution area of Exobasidum horvathianum includes Europe from the Caucasus to Poland and Asia Minor .
ecology
The host plant of Exobasidium horvathianum is Rhododendron luteum . The fungus feeds on the nutrients present in the storage tissue of the plants, its basidia later break through the leaf surface and release spores. The spores germinate into conidia or germ tubes from which new mycelium then develops.
swell
- John Frithiof Nannfeldt: Exobasidium, a taxonomic reassessment applied to the European species . In: Symbolae Botanicae Upsalienses . tape 23 (2) , 1981, pp. 1-71 .