Why everlastings don't last.
The Cape Floral Region represents one of the world's biodiversity hot spots, with a high level of plant, animal and insect endemism. The fungi occurring in this region, however, remain poorly studied. It is widely postulated that each plant species should harbour at least five to six unique fungal species, a number that we regard to be a huge underestimate. To test this hypothesis, we decided to study a single senescent flower of Phaenocoma prolifera ('everlasting'; Asteraceae) collected in South Africa, and posed the question as to how many different species of fungi could be isolated and cultivated from 10 leaf bracts. Using a damp chamber technique, numerous microfungi could be induced to sporulate, enabling most of them to be successfully isolated on artificial agar media. Isolates were subsequently subjected to DNA sequencing of the ITS and LSU nrDNA regions. During the course of this study 17 species could be cultivated and identified, of which 11 appeared to be new to science. These include Catenulostroma hermanusense, Cladosporium phaenocomae, Devriesia tardicrescens, Exophiala capensis, Penidiella aggregata, P. ellipsoidea, Teratosphaeria karinae, Toxicocladosporium pseudoveloxum spp. nov., and Xenophacidiella pseudocatenata gen. & sp. nov. Further studies are now required to determine if these fungi also occur as endophytes in healthy flowers. If this trend holds true for other plant hosts from southern Africa, it would suggest that there are many more fungi present in the Cape Floral Region than estimated in previous studies.
CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands;
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Crous
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Groenewald