A flora of the vascular plants of the Greater Mount Holyoke Range (GMHR) in Hampshire County, Massachusetts, was published in 2008. Brief, informal updates have been issued since then, but with the continued discovery of additional species, the impetus for a comprehensive update became apparent. This article reports all known changes since 2008 and discusses some of the factors contributing to these changes. The update added a net of 51 taxa to the current flora, including three new state-listed species, a county record, a species listed as historic in Massachusetts, and two taxa known from specimens but not found in the original survey. Five historical records were found. The updates came from new field collections, observations, redetermination of existing specimens, and historical records discovered subsequent to the 2008 flora. The current flora is now 878 taxa, of which 19% are considered nonnative or otherwise introduced to the GMHR. The combined current and historical flora is 918 taxa.
