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Mycology and Plant Pathology |
University of Alberta Microfungus Collection and Herbarium, Devonian Botanic Garden, Edmonton, Alberta T6G 2E1 Canada; Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9 Canada Department of Botany, The Field Museum of Natural History, Chicago, Illinois 60605-2496 USA;
ABSTRACT
Catinella olivacea is a discomycetous fungus often found fruiting within cavities in rotting logs. Because this habitat would lack the air currents upon which discomycete species normally rely for the dispersal of their forcibly ejected ascospores, we suspected an alternative disseminative strategy might be employed by this species. An examination of the development of the discomycetous ascomata in pure culture, on wood blocks, and on agar showed that the epithecium was gelatinous at maturity and entrapped released ascospores in a slimy mass. We interpreted this as an adaptation for ascospore disperal by arthropods. Developmental data also showed that C. olivacea was unusual among other discomycetes in the Helotiales (Leotiomycetes). For example, the ascoma developed from a stromatic mass of meristematically dividing cells and involved the formation of a uniloculate cavity within a structure better considered an ascostroma than an incipient apothecium. Furthermore, the ascus had a prominent ocular chamber and released its ascospores through a broad, bivalvate slit. These features, along with phylogenetic analyses of large subunit and small subunit rDNA, indicated that this unusual apothecial fungus is, surprisingly, more closely affiliated with the Dothideomycetes than the Leotiomycetes.
Key Words: Alberta, Canada apothecioid ascolocular ontogeny ascostroma bitunicate Dermateaceae Dothideomycetes Helotiales
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