The Genus Clavariadelphus in North America excluding Mexico

The genus Clavariadelphus is a group of clavarioid-cantharelloid fungi most commonly encountered in northern boreal, coniferous forests in the Northern Hemisphere. In North America, several taxa are known to extend southward into the mixed coniferous-deciduous forests of the Sierra Nevada and Rocky Mountains and into the coniferous, mixed coniferous-deciduous or deciduous forests of the Appalachian Mountains. Of the sixteen taxa of Clavariadelphus recognized from the study area, four are new to science, one is a stat. nov., and one is a comb. nov..

Data obtained through detailed morphological examinations of basidiocarps, macrochemical spot tests, somatic culture mat analyses, distribution of pistillarin in basidiocarps, and basidial nuclear phenomena were analyzed for their taxonomic value. Of these, morphological characters, and in certain taxa, macrochemical spot tests and cultural data, were most important for an accurate circumscription of species. Pistillarin distribution, while of little taxonomic significance at the species level, may be an additional character by which the subgenera and sections are delimited. Without exception, basidia of the eleven taxa examined exhibited chiastic nuclear behavior and a single post-meiotic division.

To supplement the North American material examined, an attempt was made to examine all extant type specimens, including designation of neotypes or representative material when type specimens did not exist. Descriptions of all these collections are presented. Additionally, four extralimital taxa new to science are described. A preliminary key to the world taxa of Clavariadelphus is offered to facilitate further work on the genus.