The genus Laccaria in North America excluding Mexico

The genus Laccaria comprises an important part of the North American mushroom flora north of Mexico. Nineteen species of Laccaria were recognized from the study area. Of these, seven are new to science, one is a comb. Nov., and one is reported for the first time from the geographical range.

Data obtained through detailed morphological examinations of basidiocarps and somatic culture mat studies were included in the numerical taxonomic analyses in order to objectively develoр а classification scheme based on overall phenetic similarities. Although additional analyses, undertaken to investigate the effect of using differing sets of characters were attempted, satisfactory results were obtained only when cultural data along with macro- and micro-morphological data were included. This emphasized the importance of cultural characters for the accurate circumscription of species.

In addition to an examination of North American material, an attempt was made to examine all extant type specimens, including designation of neotypes or representative material when type specimens did not exist or were unavailable. Descriptions of all of these collections are offered. To facilitate further work on the genus, a tentative key to the world taxa of Laccaria is presented.