A new and completely rewritten edition of the Provisional Host Index of the Fungi of the United States (covering the period 1888-1891) by the late Professor W. G. Farlow and A. B. Seymour, this work will be indispensable to all mycologists and phytophathologists. It contains about 80,000 names, as against 23,000 of the earlier book. The present Index includes Central America and the West Indies, Greenland and Arctic America with full synonymy so far reported on a given host up to July 1, 1927. The host families are arranged according to Dalla Torre and Harms' Genera Siphonogamarum ad Systerna Engleriana, 1900-1907 , while the specific names are arranged alphabetically.

No attempt is made to give the synonymy of hosts. The author has had cooperation of many specialists who have given freely from their exact knowledge in dealing with puzzling problems of synonymy of both fungi and hosts.