Montiaceae (Portulacineae) comprise a clade of at least 268 species plus ca. 27 subspecific taxa primarily of western North America, the Chilean Floristic Region, and temperate Australasia. This work uses existing phylogenetic metadata to elaborate a new cladistic taxonomic synthesis. A total of 24 taxa are validated, nine new and 15 necessary nomenclatural recombinations. Hypotheses of Montiaceae historical biogeographical, ecological, and phenotypic evolution are evaluated in light of recent metadata and in terms of classical, contemporary, and novel systematic and evolutionary epistemology.