Summary. The distribution and relative concentrations of muscarine and its isomers in I.nocybe species were determined. Notable was the finding that I . cinnamomea A . H . Smith, 1.geophyUa Karst. and I . Zacera (Fr.) QuSZ. contained concentrations of e$i-muscarine equal to or higher than muscarine itself.The reasons for a re-examination of the occurrence of muscarine in mushroom: were dicussed in papers No. 28 [2] and No. 29 [3] of this series. After the isolation of muscarine from Amanita muscaria (L. ex Fr.) Hooker and certain Inocybe species, the mother liquors were examined for the presence of the stereoisomers of muscarine. The presence of allo-muscarine, epi-muscarine, and possibly epiallo-muscarine, in A . muscuria and certain Inocybe species was reported 141. Later, (-)-allo-muscarine was isolated from A . muscaria [l]. During these preliminary investigations, it was suspected that the muscarine fractions of certain Inocybe species contained a higher proportion of the stereoisomers of muscarine than muscarine itself. This observation provided the impetus for the present study.Muscarine muscarine is widely distributed, and where it often occurs in relatively high concentrations, to determine to what extent the stereoisomers of this compound are distributed throughout this genus. It is felt that these data might be useful in resolving some of the inconsistencies associated with the pharmacology and biosynthesis of muscarine, and possibly contribute to the taxonomic characters of the genus Inocybe. The species selected are somewhat representative of the genus Inocybe and, except for I.subbrunnea and 1.3398, all are known to contain muscarine. The total muscarine fractip from each species was obtained by the method described subsequently. Partially purified extracts of muscarine chloride were pyrolysed, and the resulting norbases were separated, identified, and assayed according to the procedures ofThe results are summarized in the Table. The following conclusions are noteworthy. Nor-muscarine and norepi-muscarine were identified with certainty in all species examined. Norallo-muscarine was detected
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