The Thelephoraceae of North America. IV. Exobasidium

The type species of the genus is Exobasidium Vaccinii Fuck, ex Wor.Fungi parasitic in leaves, shoots, and flowers, which they deform more or less, producing on the surface of these organs an effused hymenium, rarely composed of basidia alone and more usually felt-like and composed chiefly of interwoven hyphae bearing basidia and conidiophores ; basidia simple; spores white, simple or septate.Exobasidium resembles so closely in the thinness of its fructifications such species of Corticium and Peniophora as Corticium byssinum, Peniophora asperipilata, P. pilosa, and P. subalutacea that I follow Saccardo and include it with the above genera in the Thelephoraceae.Hennings in Engler & Prantl 's 'Die Naturlichen Pflanzenf amilien, ' has raised Exobasidium to ordinal rank but this is not justified by the structure of the many fructifications of Exobasidium which I have sectioned ; the illustrations in text-books of the structure in section of the fructification are decidedly diagrammatic and simplified. .In his work already cited, Woronin gives a detailed account of the morphology and life history of Exobasidium Vaccinii and illustrates this account with three double plates.The interest in this fungus which Woronin 's work aroused has 1