A toadstool in an unusual habitat

Abstract

Growth rate, but not spore germination or sporophore production, of Asterophora lycoperdoides is enhanced by media with high ratios of organic, but not inorganic, nitrogenous compounds to carbohydrate. Carbohydrate appears essential. The effectiveness of the nitrogenous material increases with its carbon content. Much asparagine is decomposed but little of its nitrogen is assimilated, and more carbon may accumulate in the mycelium than is concurrently used from glucose. Mannitol and glycogen support less growth than glucose.Correspondingly, estimated carbon in extracts of Russula nigricans, a host, is present one and a half times as much in organic nitrogenous material as in carbohydrate.Two other mycotrophs, Asterophora parasitica and Hypocrea pulvinata, and a parasite of buds of higher plants, Fusarium lateritium, but not a lignicole, Polyporus brumalis, or a coprophile, Sordaria fimicola, are also favoured in growth by high ratios of asparagine/glucose.Growth of A. lycoperdoides and eight other hymenomycete-inhabiting fungi, A. parasitica, Hypocrea pulvinata, Apiocrea chrysosperma, Hypomyces aurantius, H. rosellus, Syzygites megalocarpus, Spinellus sp. and Chaetocladium jonesii, is only moderately or not at all impaired by M/650 KCN, but this completely inhibits four non-mycotrophs, Polyporus brumalis, Sordaria fimicola, Fusarium lateritium and Mucor ramannianus. Reports of cyanide production by hymenomycetes are mentioned.The results are tentatively interpreted as offering a partial explanation of the substratum-specificity of fungi inhabiting toadstools.