Three Pseuduvaria and a Schefferomitra species from New Guinea, and a Queensland Polyalthia species, all belonging to genera of the family Annonaceae, have been studied. The Pseuduvaria species are small rain-forest trees, of which one, designated by the herbarium voucher number TGH10530, gives positive tests for both leaf and bark alkaloids. Only the leaf alkaloids from this species have been examined, and the major alkaloids have been identified as liriodenine (1) and anonaine (2). Another species identified as Pseuduvaria cf. grandifolia (Warb.) J. Sinclair gives a positive test for bark alkaloids, but the leaves are alkaloid-negative. Liriodenine has also been isolated from this species, but the major constituent, which is considered from spectroscopic evidence to be 1,2-dimethoxynoraporphine (3), has proved very difficult to separate from another constituent, anonaine (2). The n.m.r. spectrum of the mixture shows all the signals consistent with the presence of both (3) and (2), but because it has not been possible to obtain (3) entirely pure, accurate physical constants cannot be recorded. The mixture of N-acetyl compounds prepared by reaction with acetic anhydride gives on repeated crystallization a product which shows a strong parent ion peak at m/e 323, corresponding to the N-acetyl derivative of (3), with only a relatively weak peak at m/e 307 attributed to N-acetylanonaine. The alkaloid 1,2-dimethoxynoraporphine (3) (nornuciferine) has been previously reported to occur in Nelumbo lutea. Another Pseuduvaria species (voucher number TGH11084), identified as Pseuduvaria cf. dolichonema (Diels) J. Sinclair, affords both leaf alkaloids (0.4% yield) and bark alkaloids (0.1%). Three leaf alkaloids have been characterized, but liriodenine has been shown to be absent. Two alkaloids have been identified as glaucine (4) and (+)-2-hydroxy-1,9,10-trimethoxynoraporphine (5), the latter an alkaloid recently isolated from Beilschmiedia podagrica (family Lauraceae). The third alkaloid is new and it can readily be shown from spectroscopic evidence to be 1,2,9,10-tetramethoxynoraporphine (6), the noraporphine corresponding to glaucine (4). Because of its relationship to glaucine the alkaloid is referred to as norglaucine, and it is most readily characterized in the form of its N-acetyl derivative (7). The structure of the N-acetyl compound (7) has been confirmed by its preparation from N-acetyllaurolitsine. Liriodenine does not appear to have been previously isolated from species belonging to the family Annonaceae, but its occurrence within the family is not restricted to the genus Pseuduvaria. It has also been isolated from a very complex mixture of alkaloids extracted from the Queensland species Polyalthia nitidissima Benth., and from the alkaloids from the bark of Schefferomitra subaequalis (Scheff.) Diels, a rainforest liana from New Guinea. Examination by thin-layer chromatography indicates the presence of some seven or eight alkaloids in S. subaequalis but only liriodenine and anonaine have been isolated and fully characterized.