The Thelephoraceae of North America. IV. Exobasidium

Abstract

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 Issued October 8, 1915. Note. â€" Explanation in regard to the citation of specimens studied is given in Part I,

Exobasidium dubium and E. miyabei sp. nov. causing Exobasidium leaf blisters on Rhododendron spp. in Japan

“…The taxonomy of Exobasidium has been debated because of the simple morphology of taxonomic characters and the highly variable symptoms and wide host range (Burt 1915;Ezuka 1991b;Nannfeldt 1981;McNabb 1962;Savile 1959;Sundström 1964). We compared the morphology of basidia, basidiospores, and sterigmata and the mode of germination of basidiospores.…”

Exobasidium maculosum, a new species causing leaf and fruit spots on blueberry in the southeastern USA and its relationship with other Exobasidium spp. parasitic to blueberry and cranberry

“…The genus Vaccinium, which includes wild and commercial blueberry and cranberry species, is susceptible to multiple different species of Exobasidium, many of which are host-specific (Nannfeldt 1981, Begerow et al 2002, Piątek et al 2012. Exobasidium species cause plant deformities including leaf spots, witches' broom, shoot infections characterized by reddened leaves, or galls on leaves, stems, flowers, shoots and buds (Burt 1915;Nannfeldt 1981;Chandramouli 2003;Nagao et al 2003Nagao et al , 2004Nagao et al , 2006Sinclair and Lyon 2005). Infections can be annual or perennial and local or systemic and often are characterized by a white, felt-like growth and reddish discoloration.…”

“…Although Burt (1915) and Savile (1959) proposed broad morphological species concepts within the genus and considered most species to be confined to E. vaccinii (Fuckel) Woronin, Nannfeldt (1981) postulated that species of Exobasidium are symptom specific and specialized to one or a few closely related hosts and, therefore, defined E. vaccinii as restricted to V. vitis-idaea L. (lingonberry). Molecular phylogenetic studies have supported Nannfeldt's species concept (Begerow et al 2002, Kennedy et al 2012, Piątek et al 2012.…”

Exobasidium symploci-japonicae var. carpogenum var. nov. causing Exobasidium fruit deformation on Symplocos lucida in Japan

“…Its host range is wide, and the symptoms are galls on leaves, buds, flowers, fruit, and even on trunk, leaf blister, leaf blast, shoestring leaf, and witches' bloom. The taxonomy of Exobasidium has been argued (Burt 1915;Ezuka 1991;McNabb 1962;Nannfeldt 1981;Savile 1959;Sundström 1964). These arguments are attributed to the simple morphology of taxonomic characters and the variable symptoms and wide host range of this genus.…”