The Missouri Botanical Garden purchased 1,300 acres (5.3 km2) of land immediately to the west of Pacific in 1925 when pollution from coal smoke in Saint Louis threatened the garden's extensive plant collection, notably its orchids. The orchids were moved to the land, then called the Gray Summit Extension, the following year, but were restored to the original location of the garden when pollution waned. The Missouri Botanical Garden kept the land, and over the next fifty years, amounting eventually to the 2,444 acre (9.89 km2) parcel currently known as Shaw Nature Reserve.
