Identifying synapomorphic morphological characters is needed to select and then accurately place fossils as calibrations on a phylogeny in molecular-dating analyses. The plant family Myrtaceae, with 130 genera and 5500 species, has nine different pollen types, whereas the fossil pollen record of Myrtaceae, represented by the genus Myrtaceidites, putatively extends back to the Cretaceous and also contains at least nine distinct morphospecies. To reveal potential links between extant and fossil pollen, we optimised pollen characters scored from a recent family-wide review of extant Myrtaceae pollen using scanning electron microscopy (SEM) onto a phylogeny of 111 taxa inferred from two chloroplast (matK and ndhF) and one nuclear (internal transcribed spacer, ITS) loci. Our findings indicate the potential use of colpus morphology in diagnosing pollen types in Myrtaceae, whereas the majority of character states of exine pattern, presence of apocolpial island and pollen width appear to be homoplasious. The results of the present study have implications for understanding the relationship between fossil morphospecies and extant Myrtaceae species, and their reliable choice in molecular dating.

Morphometric data have long suggested the existence of three species of Sicyos in Australia and New Zealand. Molecular data now corroborate this and place the three species in the context of the remaining 72 species of Sicyos, most of them in the New World. We here describe and illustrate Sicyos undara I.Telford & P.Sebastian from northern Queensland and S. mawhai I.Telford & P.Sebastian from New Zealand, and emend the circumscription of S. australis to account for the removal of these two extraneous elements. We also provide a key to the three species, map their ranges, and note their habitat and conservation status.

Leucopogon extremus Hislop & Puente-Lelievre, a new species of Leucopogon s. str. with a remarkably anomalous morphology, is described, illustrated and its distribution mapped. Its placement within the genus is confirmed through phylogenetic analyses of the plastid rbcL, matK, atpB–rbcL and trnH–psbA sequences.

The status of the genera of the lichen-forming fungal family Megalosporaceae is re-examined. DNA-sequence data utilising three loci and anatomical observations pertaining to the hymenium, asci and ascospores support Megaloblastenia as a distinct genus. Austroblastenia is not supported by molecular, morphological or anatomical data, which suggest that it should be subsumed within Megalospora. Consequently, the new combinations, Megalospora pauciseptata (Shirley) Kantvilas & Lumbsch and M. pupa (Sipman) Kantvilas & Lumbsch, are proposed.

The species of Acacia s.l. are currently undergoing a taxonomic upheaval. This is due, in large part, to recent molecular work that has confirmed previous morphological studies and concluded that the genus is not monophyletic. At least five monophyletic lineages have been defined within the genus and, largely on the basis of molecular data, these are distributed throughout the tribes Acacieae, Ingeae and Mimoseae of the Mimosoideae. We provide new and review previous molecular data used to redefine the generic classification of the genus into five segregate genera. The present study doubles the number of plastid base pairs compared with previous studies, to over 7 kb of aligned sequence. These data confirm previous clades and the present is the first to identify robust support for relationships among clades on the backbone of the phylogeny. The support for Vachellia is stronger than for any subclade within it. However, the support for Senegalia s.s. is weaker than it is for each of two subclades within it. There is no support for the former tribal classification with the enlarged dataset. The nomenclatural implications of which clades are recognised at a generic level are discussed.