Abstract
A description is provided for Mycosphaerella oxyacanthae, which sometimes causes lesions on leaves of Crataegus laevigata. Some information on its dispersal and transmission and conservation status is given, along with details of its geographical distribution (North America (USA), Asia (Armenia, Azerbaijan, China, Georgia, India, Iran, Kazakhstan, Kirgizstan [Kyrgyzstan], Russia, Turkey, Turkmenistan, Uzbekistan), Europe (Austria, Belgium, Bulgaria, Czech Republic, Denmark, France, Germany, Great Britain, Hungary, Italy, Latvia, Norway, Portugal, Romania, Russia (Astrakhan oblast, Kursk oblast, Saratov oblast, Stavropolskyi krai, Voronezh oblast), Sweden, Switzerland and Ukraine)) and hosts (Phoma macrostoma, Crataegus ambigua, C. beckeriana, C. chlorocarpa, C. curvisepala [syn. C. kyrtostyla], C. laevigata [syn. C. oxyacantha], C. macracantha, C. microphylla, C. mollis, C. monogyna, C. pinnatifida, C. remotilobata, C. sanguinea, C. songarica [C. songorica], C. volgensis, and Crataegus sp.).