A. Eicker

Morphology and taxonomy of South African isolates of Colletotrichum.

South African isolates of Colletotrichum Corda were examined in culture and on host material. The following eleven species are recognized: C. acutatum, C. coccodes, C. crassipes, C. dematium, C. destructivum, C. gloeosporioides, C. graminicola, C. lindemuthianum, C. musae, C. orbiculare and C. trifolii. A key for their identification is supplied. The taxonomic and nomenclatorial history of these species is discussed and their culture characteristics and morphology are fully described and illustrated. Culture characteristics are regarded as good taxonomic criteria while conidiophore structure and conidium development together with seta development and structure are regarded as less useful discriminatory characters. Appressorium dimensions and shape could be used to characterize only one species. Percurrent proliferation of some conidiogenous cells was observed in several species.

South African fungi: the genus Amanita

Thirteen species of Amanita have been recorded from South Africa, two wrongly, namely A. citrina and A. strobiliformis ( solitaria ); descriptions are given of the remainder. A. excelsa, A. muscaria, A. pantherina, A. phalloides and A. rubescens are considered to be of European origin. A. praeclara and A. roseolescens are regarded as native, as are two new taxa, A. foetidissima and A. veldiei , together with A. pleropus for which the first comprehensive account is provided. A discussion of A. praetoriae is included.

The mycoflora of an alkaline soil of the open-savannah of the Transvaal

The microfungi of an alkaline soil from an open-savannah in the Pretoria district of the Transvaal were surveyed using the dilution plate technique, the soil plate technique and a soil washing method. Over 14 months 127 species representing 53 genera were isolated. The most prevalent species found were Penicillium spp.; Fusarium spp.; Trickoderma viride; Gliocladium roseum; Aspergillus spp. ; Mucor spinosus; Spicaria violaceae and Chaetomium globosum . The results are discussed with particular reference to comparable surveys carried out in the Western Transvaal.

Branching in Spadicoides

The presence or absence of branched conidiophores is abandoned as a diagnostic generic character in Spadicoides . The generic circumscription is emended and restricted to the formation of solitary conidia and the names of four species which show catenate conidia are transferred to Diplococcium — D. catenulatum comb.nov., D. constrictum comb.nov., D. grovei comb.nov. and D. stoveri comb.nov.

’n Mikrobiologiese studie van ‘kaal kolle’ in die Giribesvlakte van Kaokoland, S.W.A.-Namibië

A microbiological study of ‘bare patches’ in the Giribes plains of Kaokoland, S.W.A.-Namibia. A study was made of the density of the bacteria and fungus populations in, on the edges of, and between ‘bare patches’ in the Giribes plain, Kaokoland. The density of the microbial populations showed, with the exception of anaerobic bacteria, a close relation to the density of the higher plants of these soils. The soil samples of the bare patches had the lowest microbial population level while the edge of the patches had the highest microbial population. Sixty three species of fungi belonging to 37 genera in total were isolated from these three soil types. The nature of the fungus population closely resembles those of other dry areas. Aspergillus and Penicillium species were generally the most numerous while many yeasts and dark coloured Dematiaceae also occured quite commonly. S. Afr. J. Bot . 1982, 1: 69-74

Microfungi from surface soil of forest communities in Zululand

The mycoflora of the soil of two areas in Zululand with markedly different soils and vegetational cover was studied over a period of i year. One hundred and twelve species representing forty-three genera were isolated from the two sites. Of these, ten genera and forty-one species were new records for S. Africa. The fungi isolated include twenty-one phycomycetes, nine asco-mycetes, one basidiomycete and eighty-one fungi imperfecti. The most common genera encountered were Penicillium and Trichoderma , followed by Gongronella, Candida, Absidia, Fusarium, Cunninghamella, Mucor, Humicola and Paecilomyces .

Vertical distribution of fungi in Zululand soils.

It was found that the number of fungus species and colonies decreased with depth, the rate of reduction being mainly dependent on the soil moisture content. In one profile an increase in colony numbers and number of species at deeper horizons was probably the result of a marked increase in the carbon content of these horizons. The vertical distribution of the more important species was investigated in detail.

Species of Termitomyces occurring in South Africa

Seven species of Termitomyces were identified — T. clypeatus, T. microcarpus, T. sagittiformis, T. schimperi, T. striatus, T. umkowaani and T. reticulatus sp. nov. The wood-destroying termite Odontotermes badius was found to be the most commonly associated termite species. Termitomyces sagittiformis was associated with Odontotermes latericius, a new record. The morphologies of the Termitomyces spp. are described and illustrated and their occurrence, distribution and termite associations are discussed.

Amatoxins and phallotoxins in indigenous and introduced South African Amanita species

The production of lethal amatoxins and phallotoxins in species of Amanita from South Africa was investigated by HPLC (High Performance Liquid Chromotography) analyses. The indigenous mushrooms Amanita foetidissima and A. pleropus tested negative for production of these toxins. Several introduced species were analysed; of these, A. phalloides var. phalloides, A. phalloides f. alba and A. reidii contained amatoxins and phallotoxins. Despite reports of rapid degradation of phallotoxins upon drying, phallotoxins and amatoxins were both readily detectable in dried herbarium specimens up to 17 years old. Previous reports of phallotoxins in A. rubescens were not substantiated.

Cultural studies on the genus Termitomyces in South Africa. I. Macro- and microscopic characters of basidiome context cultures

Characteristics of basidiome context cultures of five South African species of Termitomyces were investigated, namely T. umkowaani, T. reticulatus, T. sagittaeformis, T. clypeatus and T. microcarpus. Microscopic characters of the cultures were very similar but macroscopic characters differed markedly. It was possible to distinguish between different species by relying strictly on macroscopic characters. Growth characters did not change when the nutrient medium and incubation conditions were standardised, and proved to be a reliable taxonomic criterion for the species under investigation. With the exception of T. microcarpus, all the species produced conidiophores and holoarthric conidia in culture with numerous aged, inflated, ungerminated conidia (sphaerocysts). With the exception of T. clypeatus, conidiophores were aggregated into spherical, farinaceous sporodochia which resembled comb sporodochia. Conidiophores of T. clypeatus were closely compacted to form synnematous structures. Cultures of T. microcarpus exhibited typical basidiomycetous growth characters. However, they differed significantly from cultures of the other species which, unlike T. microcarpus, formed conidiophores and produced a raised, tough, cerebriform mycelium mat which could be considered a stroma. It is suggested that T. microcarpus should be transferred to the genus Podabrella Singer.