Taxonomy of the <i>Typhula ishikariensis</i> complex in Russia

Abstract

The purpose of this publication is to show the history of the taxonomy of the Typhula ishikariensis complex and to provide more detailed geographical descriptions of those fungi in Russia. Three features on the description of this complex species are noted: morphological, crossing and molecular. Often, species described on different host plants have been recognized as synonyms of another previously described species, for example, T. humulina isolated from hop rhizomes and T. graminearum from first year seedlings of Pinus sylvestris and grass weeds have been synonymized with Typhula idahoensis. The latest work by Hoshino et al. distinguished four taxa (three species) based on dendrograms obtained by ITS and ribosomal DNA sequencing, crossing results, morphological and physiological characters: T. ishikariensis var. ishikariensis, T. ishikariensis var. idahoensis, T. hyperborea, and T. canadensis. T. ishikariensis var. idahoensis was found only in North America, and the last two species (T. hyperborea and T. canadensis) mainly in areas with extreme winter conditions. In Russia, Typhula ishikariensis var. ishikariensis, was recorded in the European part of Russia beyond the Arctic Circle: Apatity (Kola Peninsula), in places with a temperate climate: Moscow, St. Petersburg, the republics of Chuvashia and Mari El; and in Asia with a more severe climate: Sverdlovsk Region, Novosibirsk, Irkutsk Region (Hamar-Daban) and Sakhalin. T. canadensis and, presumably, the oldest T. hyperborea, inhabit mainly in areas with unstable and severe winter climates. T canadensis in Russia was noted by us in Asia in the Baikal region in the Ice Age refugium Khamar-Daban, Kamchatka and Sakhalin, and T. hyperborea in Asia in the Sverdlovsk region, Novosibirsk, Kamchatka and Chukotka (Anadyr), along with the European regions of Russia with a temperate climate in the Volga republics of Mari El and Tatarstan. These areas are characterized frequent autumn frosts, which promoted competition with another snow mold pathogen, the necrotroph Sclerotinia borealis. Underground damage of plant tissues, such as tulip bulb bases and roots, and hop rhizomes by T. ishikariensis var. ishikariensis occurred only in Russia. Perhaps the diversity in winter climate evolved and preserved diverse taxa, including ancestral forms. Obviously, such climatic fluctuations evolved organisms capable of survival under unstable stressful conditions, especially when climatic conditions change.