Fungal Diversity 37 Ceratocystis and Ophiostoma species, including three new taxa, associated with wounds on native South African trees Kamgan, N.G. 1* , Jacobs, K. 2 , de Beer, Z.W. 1 , Wingfield, M.J. 1 and Roux, J. 1 1 Department of Microbiology and Plant Pathology, DST/NRF Centre of Excellence in Tree Health Biotechnology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa 2 Department of Microbiology, University of Stellenbosch, Stellenbosch, South Africa Kamgan, N.G., Jacobs, K., de Beer, Z.W., Wingfield, M.J. and Roux, J. (2008). Ceratocystis and Ophiostoma species including three new taxa, associated with wounds on native South African trees. Fungal Diversity 29: 37-59. Fungal species in Ceratocystis and Ophiostoma include important pathogens, associated with insects that typically infect wounds visited or made by their vectors. There are few reports of these fungi from the African continent and little is known regarding their relative importance in the area. In this study, species of Ceratocystis and Ophiostoma were collected from wounds on native tree species in selected areas of South Africa and they were identified based on morphological and DNA sequence comparisons. Ceratocystis and Ophiostoma species were collected from eight different native trees including six different families. These included Ophiostoma quercus, Pesotum fragrans, Ceratocystis albifundus as well as an undescribed Ophiostoma sp. and two undescribed Ceratocystis spp. The new Ceratocystis spp. are described here as Ceratocystis savannae sp. nov. and Ceratocystis tsitsikammensis sp. nov. and the Ophiostoma sp. as Ophiostoma longiconidiatum sp. nov. In pathogenicity tests, C. tsitsikammensis sp. nov. resulted in significant lesions on Rapanea melanophloeos trees, while C. savannae sp. nov. produced very small lesions on Acacia nigrescens and Sclerocarya birrea trees. Key words: Africa, fungal pathogens, ophiostomatoid fungi Article Information Received 23 August 2007 Accepted 10 January 2008 Published online 31 March 2008 * Corresponding author: G. Kamgan Nkuekam; e-mail: gilbert.kamgan@fabi.up.ac.za Introduction Species of Ceratocystis Ellis & Halst. and Ophiostoma Syd. & P. Syd. and their anamorph genera are collectively referred to as the ophiostomatoid fungi. This name arises from their morphological similarities and particularly convergent evolution of structures adapted to insect dispersal (Wingfield et al., 1993). Fungi in these genera are characterized by their dark, globose ascomata with elongated necks giving rise to sticky spores at their apices. Asci generally disappear early in the development and are seldom seen (Upadhyay, 1981). It is now widely accepted that Cerato- cystis and Ophiostoma are distinct genera, in separate orders of the Ascomycetes. Ceratocys- tis spp. have Thielaviopsis anamorphs with enteroblastic conidiogenesis (Paulin-Mahady et al., 2002) and reside in the order Microascales Luttr. ex Benny & Kimbr. (Hausner et al., 1993; Spatafora and Blackwell, 1994; Paulin- Mahady et al., 2002). Ophiostoma sensu lato is recognized as a generic aggregate in the order Ophiostomatales Benny & Kimbr. (Hausner et al., 1993; Spatafora and Blackwell, 1994). Ophiostoma s. l. includes Ophiostoma Syd. & P. Syd. sensu stricto with Pesotum J.L. Crane & Schokn. and Sporothrix Hektoen & C.F. Perkins anamorphs, Ceratocystiopsis H.P. Upadhyay & W.B. Kendr. with Hyalorhinocla- diella H.P. Upadhyay & W.B. Kendr. anamor- phs, and Grosmannia Goid. with Leptogra- phium Lagerb. & Melin anamorphs (Upadhyay, 1981; Zipfel et al., 2006). These genera, alth- ough phylogenetically distinct, have clearly evolved similar morphologies in response to the similar niches and the survival strategies that they have adapted (Hausner et al., 1993; Spatafora and Blackwell, 1994; Wingfield et