Cultures were extracted with BuOH and the residue was purified by SiO2 column chromatography with C6H6-EtOAc. First fraction: ergosterol peroxide C28H44O3, m.p. 182–184°, [α]D -23.5° (EtOH). Ergosterol peroxide acetate, m.p. 199-201° [4]. M.p., TLC, IR, PMR and MS are identical with those of a pure sample prepared by synthesis [5]. Second fraction: (ergosta-7:22-diene-3β:5α:6β-triol) cerevisterol C28H46O3 [6], m.p. 252–255°, [α]D = 80.5° (pyridine), MS m/e 412 (M+ -18), 394, 376, 361, 269, 251, 69. It gives a diacetate C32H50O5, m.p. 167–171°, [α]D –147° (EtOH). All the analytical and spectroscopical data were identical with those of a pure sample prepared by synthesis [7]. Mycena pura (Fr.) Kummer is one of the most common and widely distributed fungi. A PC survey revealed that the fruit bodies of this fungus contained several unusual amino acids. We have now identified three which give brown colorations with ninhydrin. From their positions on 2D-chromatograms, one is γ-methyleneglutamic acid and the other two are the ethylidene and propylidene homologues. They were isolated by fractionation first on a column of Dowex 1 in acetate form, and subsequently with a cellulose column. L-γ-Methyleneglutamic acid was first isolated from young plants of Arachis hypogaea [1] and subsequently from some other legumes such as Amorpha fruticosa [2] and Tetrapleura tetraptera [3] from the Liliaceae, Tulipa gesneriana [4,5], Lilium maximowiczii [6], Lilium candidum [7] and from a fern Phyllitis scolopendrium [8]. The next higher homologue, L-γ-ethylideneglutamic acid was discovered from fruit capsules of Tulip gesneriana [9]. This amino acid was reported to occur also in two legumes, Tetrapleura tetraptera [3] and Guilandina crista [10]. The identifications of these two amino acids from Mycena pura were based on elementary analysis, optical rotation and comparison of their IR spectra with those of the authentic specimens isolated from tulip. The evidence for the occurrence in nature of L-γ-propylideneglutamic acid, however, has not yet been reported. The elementary analysis of the third amino acid isolated from this fungus was in good agreement with the formula C8H13NO4, and on hydrogenation in the presence of Adams platinum catalyst it absorbed one mole hydrogen and changed to the substance, which gave a normal violet ninhydrin coloration. The Rf of the hydrogenation product was much higher than that of the original amino acid on cellulose-TLC with the solvent (a) as in the case of L-γ-methyleneglutamic acid and its saturated form. Additionally, the hydrogenation product was separated into two components of approximately equal amount on PC with the solvent (c)[11]. They correspond presumably to threo- and erythro-forms of γ-propylglutamic acid. The oxidation in diluted H2SO4 gave aspartic acid. These results showed that the third amino acid is γ-propylideneglutamic acid. The shift of [α]D by the addition of HCl suggests that this amino acid belongs to the L-series. Finally the NMR spectrum was determined in D2O and the results were consistent with the proposed structure. Doyle and Levenberg [1] reported recently a new amino acid L-3-(3-carboxy-4-furyl)alanine from Phyllotopsis nidulans (Pers. ex Fr.) Sing. Independently we also isolated the same amino acid from another fungus, Tricholomopsis rutilans (Fr.) Sing. Identification was based on IR and TLC comparison with an authentic sample from Phyllotopsis.