A checklist of all species of bryophytes, lycophytes, ferns, gymnosperms and angiosperms that are found in the wild (native, naturalised and casual) in Singapore is presented. We have attempted to account for all names of species and infraspecific taxa that have ever been recorded for Singapore, along with the pertinent publications that reported each of these names. For each currently accepted name, the synonyms of relevance for Singapore are included. The native or non-native status for all taxa is given, along with the most recent national conservation assessment applied to each native taxon. If we were aware that the most recent assessment required an update, the taxon is newly assessed here. The checklist includes 2654 native taxa, 479 naturalised/casual taxa and 101 cryptogenic taxa.

Recent molecular phylogenetic studies in Chrysobalanaceae as well as new analyses presented in this study cast doubt on the monophyly of the three largest genera in the family, Couepia, Hirtella and Licania. Couepia, a Neotropical genus, had species appearing in four separate clades, the majority of species sequenced, however, form a highly supported clade, referred to here as core Couepia (including the type species). These results lend support to a revised taxonomy of the genus, and to resolve Couepia as monophyletic the following taxonomic changes are here proposed: Couepia recurva should be transferred to Hirtella, C. platycalyx transferred to Licania, C. longipendula and C. dolichopoda transferred to Acioa, and a new genus, Gaulettia, is proposed to accommodate species of the Gaulettia clade and allies.