The affinities of the Australian monotypic endemic family Akaniaceae, traditionally assigned to the Sapindales, are reassessed on the basis of comparative sequence data for the chloroplast encoded gene, rbcL. Cladistic analyses show Akania to cluster robustly with Bretschneidera and then Tropaeolum, within the clade of glucosinolate Capparalean families. Eight species representing six other families assigned to the Sapindales, plus Leitneria, formed a monophyletic cluster in 100% of trees in a bootstrap analysis with 500 replicates. This Sapindalean clade is shown to be supported by 17 synapomorphs, only one of which occurs in Akania. Relationships at the ordinal level, among the Sapindalean, Malvalean, Capparalean and Myrtalean clades, are, however, not well resolved. While the most parsimonious arrangement has the Malvales as sister-group to the Sapindales, with the Capparalean and Myrtalean clades joining in sequence, the occurrence of an apomorphic triplet of bases at positions 294–6 in all members of the Malvales, Myrtales and Sapindales so far examined is tentative evidence that these orders may constitute a monophyletic group.

Dacrydium Sol. ex Lamb. emend. de Laub. is redefined to include only those species belonging to section B (Florin 1931; de Laubenfels 1969). The remaining species are assigned to Lepidothamnus Phil. (two species from New Zealand, one from Chile). Lagarostrobos gen. nov. (one species from New Zealand. one from Tasmania) and Halocarpus gen. nov. (three species from New Zealand). Ovule orientation, one of the main character-states used to define Dacrydium s.l., is reexamined and shown to be in accord with the new taxonomic arrangement. Lepidothamnus fonkii Phil. is reinstated and seven new combinations are made, viz. Lepidotharnnus intermedius (T. Kirk) C. J. Quinn, L. laxifolius (Hook. f.) C. J. Quinn, Halocarpus bidwillii (Hook. f. exT. Kirk) C. J. Quinn, H. biformis (Hook.) C. J . Quinn, H. kirkii (F. Muell. ex Parl.) C. J. Quinn, Lagarostrobos colensoi (Hook.) C. J . Quinn and L. franklinii (Hook. f.) C. J. Quinn. A key to the genera in the Podocarpaceae is also given.

Descriptions are given of the anatomy of the pericarp in representatives of 28 genera of the Simaroubaceae sensu lato, including Stylobasium, as well as the ontogeny of the endocarp in 9 of them. There is marked heterogeneity in the family in both pericarp structure and endocarp ontogeny. Eight different endocarp types are recognised, the distribution of which shows considerable correlation with the subfamilial classification of Engler. This study provides further evidence that the family in the broad sense is an artificial assemblage. Endocarp structure provides support for the inclusion of both Recchia and Stylobasium in the Surianoideae. Guilfoylia has no recognisable endocarp; the occurrence of periclinal divisions within the inner protoderm of young pericarps suggests that this is a derived condition. The inclusion of Allantospermum and Nothospondias within the Irvingioideae and Simarouboideae respectively is not supported by their pericarp structures.

Parsimony analysis of matK sequence data for representatives of Myrtaceae s.1. provides evidence of its potential in phylogenetic inference in this family. Psiloxylon and Heteropyxis comprise a robust clade, basal to representatives of Myrtaceae s. str., and strongly clustered with it. In a limited sample of Myitaceae s. str., several strongly supported groups are identified: the myrtoid genera (excluding Syzygium), representatives of the Chamelaucium alliance, and the Chamelaucium plus Leptospennum alliances.

Perispore morphology of the Australian members of the Aspleniaceae is examined with use of both the light and scanning electron microscopes. A range of character states is described, and suitable terminology is defined. The results are used in conjunction with other morphological data to suggest a tentative taxonomic grouping of the Australian species.