This volume contains descriptions of direct observations on, and illustrations of all known American species of the family Saprolegmiaceae. Notes are added on related families, as Leptomitaceae, Blastocladiaceae, and Monoblepharidaceae. Originally published in 1923. A UNC Press Enduring Edition -- UNC Press Enduring Editions use the latest in digital technology to make available again books from our distinguished backlist that were previously out of print. These editions are published unaltered from the original, and are presented in affordable paperback formats, bringing readers both historical and cultural value.