The basidiomycete fungus Sparassis crispa produced three antifungal compounds during submerged culture in 2 % malt broth. One compound appeared to be sparassol (methyl-2-hydroxy-4-methoxy-6-methylbenzoate), first characterized in 1924. The other two, termed ScI and ScII, exhibited considerably greater antifungal activity than did sparassol against Cladosporiurn cucurnerinurn, and were characterized as methyl-2,4-dihydroxy-6-methylbenzoate (methyl orsellinate) and an incompletely determined methyl-dihydroxy-methoxy-methylbenzoate, respectively. Both compounds were found in the decayed wood of trees, where their presence was diagnostic of S. crispa infection. The possible ecological role of these compounds is discussed.

Summary The interaction phenomenon between cultures of Polyporus schweinitzii has been investigated and used to determine the natural distribution of different strains of this fungus in conifer plantations. The interaction behaviour of synthetic heterokaryons has shown that those derived from the pairing of completely unrelated basidiospores are those most likely to simulate the interaction potential of wild strains. The development of interacting strains from genetically complex polysporous mycelia is discussed.

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Case reports are described of individuals who developed acute contact dermatitis after contact with the resin from the Rhus verniciflua (Toxidendron vernicifluum). Potential problems from possible extensive urban planting of this species are discussed.