botanical garden in St. Louis, Mo., U.S. It is most notable for its Climatron, a geodesic-dome greenhouse in which 1,200 species of plants are grown under computer-controlled conditions simulating a rainforest. The 79-acre (32-hectare) garden also has the largest traditional Japanese garden in North America. The herbarium contains about 4.5 million specimens, some dating from the 18th century. Privately administered, the garden was established in 1859 as the gift of Henry Shaw, a merchant. The garden's periodical Missouri Botanical Gardens Bulletin contains material of interest to the general public, and its botanical reference library is one of the world's finest.