Gymnosporangium clavariiforme. [Descriptions of Fungi and Bacteria].
Abstract A description is provided for Gymnosporangium clavariiforme. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Aecia principally on hawthorn (Crataegus), also recorded on pear (Pyrus communis), quince (Cydonia vulgaris), Amelanchier, Aronia, Cotoneaster and Sorbus. Telia on Juniperus communis and other species of the 'oxycedrus' group. DISEASE: European hawthorn rust. Aecia on leaves, stems and fruit. Telia on long fusiform swellings or cankers on branches; sometimes witches' brooms present. GEOGRAPHICAL DISTRIBUTION: Throughout Europe, from Scandinavia, Britain and Spain to the Middle East in Asia. Also in India, Kamchatka, Korea and Japan. In North America, across southern Canada, northern and central USA from coast to coast. Also reported from N. Africa and found in New Zealand but eradicated.