Recent studies of the New England flora have evaluated changes within specific geographies over a relatively long period, typically a time interval of a century or more. Here, I document floristic changes in a suburban Massachusetts location, Massachusetts Audubon Society's Broadmoor Wildlife Sanctuary, by comparing plant records from 1969 to 1980 with a survey conducted in 2008–2009. The 2008–2009 survey found a relatively high total species richness (499 species) on the 246 ha property, but lower than the 562 species reported from 1969 to 1980. A total of 177 species were not refound (31% of the original flora), and 114 species (22% of the 2009 flora) were added. With the exception of four deliberately introduced grasses and five invasive species, the additions were long-lived perennial species likely to have been present but overlooked in the prior survey. The loss of species may be attributed to several factors, including natural succession following the abandonment of agriculture, deer browse, and changes in wetland hydrology caused by beavers.