Typhula ishikariensis and its varieties, var. idahoensis comb.nov. and var. canadensis var.nov.

Abstract

On genetical evidence Typhula FW, T. idahoensis Remsberg, and T. ishikariensis lmai should be considered as one species, and by priority the T. ishikariensis applied to it. Based on morphological characters the following taxonomic ranking is suggested: T. ishikariensis Imai var. ishikariensis, T. ishikariensis Imai var. idahoensis (Remsberg) comb.nov., T.ishikariensis Imai var. canadensis Smith & Årsvoll var.nov.Within this Typhula complex the latter two varieties differ most clearly morphologically, but are most closely related genetically. They are both found only in North America, while var. ishikariensis also occurs in Europe and Asia. Var. canadensis can be distinguished morphologically from the other two varieties by its smaller sclerotia and sporophores, by its more profuse production of aerial mycelium in culture, and the tendency of its sclerotia to be produced in bands, radial rows, and suspended in the aerial mycelium rather than in concentric rings. The only reasonably reliable way of separating the other two varieties is on sclerotial characters. Rind cells of var. idahoensis are more irregular in outline, with more lobate, occasionally digitate cells than var. ishikariensis.