Biotype differentiation in the Typhula ishikariensis complex and their allopatry in Hokkaido.

Typhula ishikariensis isolates were collected from various parts of Hokkaido. There were two genetically different groups which did not mate with each other; one was termed biotype A, and the other was further divided into two by cultural characteristics, i.e., biotypes B and C. Biotype A was identical to T. ishikariensis and T. ishikariensis var. ishikariensis. Biotype B was not identical to T. idahoensis or T. ishikariensis var. idahoensis. Biotype C was similar to T. ishikariensis var. canadensis. Biotype A tended to occur inland where deep snow cover lasts for a long time. Biotype B was obtained mainly from the coastal regions where snow cover is thin and short in time. The distribution of biotype C was irregular. Taxonomic significance of the genetics and allopatry in the T. ishikariensis complex is discussed.