Montiaceae (Portulacineae) comprise a clade of at least 270 species primarily of western America and Australia. This work uses existing phylogenetic metadata to elaborate a new cladistic taxonomic synthesis, and clarifies morphological circumscriptions of several poorly known species. A total of 21 taxa are validated, seven new and 14 necessary nomenclatural recombinations). Hypotheses of Montiaceae historical biogeography and phenotypic evolution are evaluated in light of recent metadata.