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The major alkaloids of Anthocercis tasmanica are shown to be hyoscine and nicotine.

The original source of tasmanone appears to have been Eucalyptus tasmanica rather than E. risdoni or E. linearis. A far richer source has been found in E. camfieldii. Tasmanone has been shown to be a tautomeric mixture of enols (IV) and (V). The major isomer forms approximately 70% of the mixture.

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Of the new non-phenolic alkaloids previously reported in the bark of Atherosperma moschatum Labill., atherospermidine has been shown to have the methoxylspermatheridine structure (II), while atherosperminine (VIII) and a further new base, methoxyatherosperminine (IX), have proved to be members of the small group of phenanthrene alkaloids.

From a nuclear magnetic resonance study of the tautomerism of tasmanone and 1,1,3,3-tetramethylphloroglucinol (syncarpic acid), it is deduced that tasmanone consists of a mixture of tautomers (I) and (II) with the tautomer (I) present in the larger proportion. Similarly it is deduced that the tautomers of agglomerone (XI; R = CHMe2), 3-acetyl-O-methylfilicinic acid (XI R; = Me), ceroptene (XI; R = CH=CHPh), and usnic acid (XIII) with the extended conjugation are the more stable and populated ones.

The bark of Atherosperma moschatum Labill. of the family Monimiaceae contains the known bisbenzylisoquinoline alkaloids berbamine (1.6 per cent.) and isotetrandrine (0.06 per cent.), together with isocorydine (0.007 per cent.) and three new alkaloids atherosperminine, C20H23O2N (0.005 per cent.), atherospermidine, C18Hl3O4N (0 006 per cent.), and spermatheridine, C17H11O3N (0.002 per cent.). The last two alkaloids are bright yellow and weakly basic. In addition to the bases listed above the leaves contain a trace of another alkaloid spermatherine. Both bark and leaves contain . phenolic alkaloids which were not further investigated. The position of the hitherto unlocated hydroxyl group in berbamine is unequivocally established by fission of O-ethylberbamine with sodium in liquid ammonia.

The isolation and structural determination of haemodorin, a new phenalenone pigment obtained from Haemodorum distichophyllum (Hook.) (Haemodoraceae), is described.

Bark of the New Caledonian monimiaceous plant Nemuaron vieillardii contains the alkaloids laurotetanine, N-methyllaurotetanine, norisocorydine, atheroline, O-methylflavinantine, and a new bisbenzylisoquinoline alkaloid nemuarine, which is the major alkaloid of the leaves. Nemuarine is shown to have a novel structure with a 5-6? ether link between the isoquinoline residues.

The mass spectra of a series of alkaloids of the spermatheridine group, together with those of their alkoxy derivatives, are reported and discussed. The characteristic fragmentation processes, substantiated by appropriate metastable peaks, exact mass measurements, and in some cases by deuterium labelling, facilitate the location of substituents in the tetracyclic system. A structure for moschatoline is deduced from a consideration of the mass spectra of its derivatives.